Search

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to evaluate the effect of sward diversification combined with a reduction of chemical nitrogen (N) fertilizer on the performance of spring-calving grazing dairy cows within a farm systems experiment. Three farmlets were created: a monoculture of perennial ryegrass (Lolium perenne L.; PRG) fertilized with 250 kg N/ha (PRG-250N), a PRG–white clover (Trifolium repens L; WC) sward fertilized with 125 kg N/ha (PRGWC-125N), and a multispecies sward (MSS) comprising grasses, legumes, and herbs, also fertilized with 125 kg N/ha (MSS-125N). Each farmlet had its own herd of dairy cows on a total area of 18.7 ha divided into 20 paddocks. Each herd comprised pure Holstein-Friesian (HF) and HF–Jersey crossbred (JFX) animals, and cows were randomly assigned through the 3 treatments. For 3 years (2021 to 2023), the performances of both swards (grass yield, botanical composition, nutritive value) and grazing animals (milk production and composition, BW, and BCS) were recorded. We found no significant differences in pasture production or sward nutritive value between sward systems, and grazing season length was also similar (264 d). On average over the 3 years, PRGWC-125N contained 150 g/kg DM of legumes, and MSS-125N contained 160 g/kg DM legumes, 130 g/kg DM plantain, and 40 g/kg DM chicory. Both individual cow milk and fat plus protein (milk solids) yield were lower for PRG-250N (5,018 and 452 kg, respectively), intermediate for PRGWC-125N (5,139 and 463 kg, respectively), and highest for MSS-125N (5,297 and 476 kg, respectively) whereas milk and milk solids production per hectare from grazing were similar during the study period (11,523 and 1,016 kg/ha, respectively). Breed also had a significant effect, with the JFX having lower milk yield but higher fat and protein concentration compared with HF. This resulted in higher milk solids production per kilogram of BW for the JFX compared with HF (0.96 and 0.87 kg milk solids/kg BW, respectively). The results of this study highlight the possibility for more diverse pastures to reduce chemical N fertilizer input requirements and maintain pasture productivity while increasing animal performance within pasture-based spring-calving systems. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify the farm gate nitrogen (N) offset potential of perennial ryegrass (Lolium perenne L.; PRG) white clover (Trifolium repens L.; WC) swards by comparing the herbage and milk production from dairy farmlets that were simulations of full farming systems. A study was established where 120 cows were randomly assigned to 4 farmlets of 10.9 ha (stocking rate: 2.75 cow/ha), composed of 20 paddocks each. Cows were fed 526 kg of DM of concentrate on average each year. The 4 grazing treatments were PRG-only at 150 or 250 kg of N/ha and PRG-WC at 150 or 250 kg of N/ha. Cows remained in their treatment group for an entire grazing season and were re-randomized as they calved across treatments each year. As cows calved in the spring as standard practice in Ireland, they were rotationally grazed from early February both day and night (weather permitting) to mid-November, to a target postgrazing sward height of 4.0 cm. Mean sward WC content was 18.1% and 15.4% for the 150 and 250 kg of N/ha PRG-WC treatments, respectively over the 3-yr period. When WC was included, lowering the N rate did not reduce pregrazing yield, pregrazing height, or herbage removed, but those factors decreased significantly when WC was absent. Total annual herbage DM production was 13,771, 15,242, 14,721, and 15,667 kg of DM/ha for PRG-only swards receiving 150 or 250 kg of N/ha and PRG-WC swards receiving 150 or 250 kg of N/ha, respectively. In addition, when WC was present, compressed postgrazing sward heights were lower (4.10 vs. 4.21 cm) and herbage allowance (approximately 17 kg/cow feed allocation per cow per day) higher than the high-N control (+ 0.7 kg of DM/cow per day). There was a significant increase in milk production, both per cow and per hectare, when WC was included in PRG swards. Over the 3-yr study, cows grazing PRG-WC had greater milk (+304 kg) and milk solids (+31 kg of fat + protein) yields than cows grazing PRG-only swards. This significant increase in milk production suggests that the inclusion of WC in grazing systems can be effectively used to increase milk production per cow and per hectare and help offset nitrogen use. This result shows the potential to increase farm gate N use efficiency and reduce the N surplus compared with PRG-dominant sward grazing systems receiving 250 kg of N/ha, without negatively affecting milk solids yield or herbage production, thus increasing farm profit by €478/ha. [ABSTRACT FROM AUTHOR]

This experiment investigated the variation in enteric methane production and associated gas exchange parameters, nutrient digestibility, rumen fermentation, and rumen microbiome when a range of silages based on different forage types (grass or clover), and different species within the 2 types, were fed as the sole feed to heifers. Three grass species (perennial ryegrass, festulolium, and tall fescue) and 2 clover species (red clover and white clover) were included. Perennial ryegrass was harvested at 2 maturity stages in the primary growth, white clover was harvested once in the primary growth, and 4 cuts of festulolium and tall fescue and 3 cuts of red clover were harvested during the growing season, giving 14 different silage batches in total. Sixteen Holstein heifers 16 to 21 mo old and 2 to 5 mo in pregnancy were fed the silages ad libitum as the sole feed in an incomplete crossover design. Each silage was fed to 4 heifers, except for the 2 perennial ryegrass silages, which were fed to 8 heifers; in total 64 observations. The CH 4 production was measured for 3 d in respiration chambers. Heifers fed clover silages had higher dry matter intake (DMI) compared with heifers fed grass silages, and heifers fed tall fescue silages had the numerically the lowest DMI. Compared with grass silages, feeding clover silages led to higher crude protein digestibility but lower neutral detergent fiber (NDF) digestibility. Rumen pH was higher in heifers fed clover silages compared with those fed grass silages. Based on composition analysis, the rumen microbiota of the heifers clustered clearly according to forage type and species. More specifically, 7 of the 34 dominating rumen bacterial genus-level groups showed higher relative abundances for the clover silages, whereas 7 genus-level groups showed higher abundances for the grass silages. Methane yield was higher for heifers fed grass silages than for those fed clover silages when methane production was related to dry matter and digestible organic matter intake, whereas the opposite was seen when related to NDF digestion. The gross energy lost as methane (CH 4 conversion factor, %) reduced from 7.5% to 6.7%, equivalent to an 11% reduction. The present study gives the outlines for choosing the optimal forage type and forage species with respect to nutrient digestibility and enteric methane emission in ruminants. [ABSTRACT FROM AUTHOR]

Agricultural intensification reduces not only biodiversity in agroecosystems but also key ecosystem functions such as soil fertility. By reintroducing biological diversity in fields, weeds may enhance soil biological fertility through their influence on crop microbiota. However, letting weeds grow in crop fields will depend on weed competitiveness, farmers' perception and acceptance, and on crop management, which influences the occurrence and the abundance of weeds in the field. This study assessed the use of eight weed species to modify wheat plant root endospheric mycobiota, and the applicability of using these plants for mycobiota enrichment in the field. By combining controlled lab experiments and field studies, we demonstrated that weeds act either as a refuge for a high diversity of fungi or as a vector for transferring fungi to the crop, particularly symbionts. Weeds differed in their competitive effect on wheat growth and only three species significantly reduced wheat growth. Interviews with farmers' revealed that weed species were better known and more appreciated in crop fields by organic farmers than by conventional farmers. Floristic surveys confirmed that both weed occurrence and cover were higher in organic fields than in conventional fields. A multicriteria analysis showed that Trifolium repens and V. persica had the highest potential for promoting wheat plant mycobiota. Among the weed species tested, these two are worth considering as auxiliaries to improve soil biological fertility in crop fields. Their use with the goal of selecting appropriate crop mycobiota should be relatively easier in organic farms where weeds are better accepted, whereas their use in conventional farms would require raising farmers' awareness of the benefits of weeds for soil fertility. • Weeds influence wheat root endospheric mycobiota. • Weeds harbour diverse fungi (refuge effect) and transfer numerous fungi to wheat (vector effect). • Weeds occur more in organic fields and are more positively perceived by organic farmers. • Wheat growth depletion differs among weed treatments • Some weed species could be effective auxiliaries for improving soil fertility. [ABSTRACT FROM AUTHOR]

The exacerbation of plant invasion by microplastics attracted widespread attention. Pulse resource hypothesis is popular theory to elucidate plant invasion. Our previous work demonstrated biodegradable microplastics (BMPs) could increase the arbuscular mycorrhizal fungi (AMF) colonization rate. Reportedly, AMF can enhance rhizobia colonization. Therefore, we infer the coexistence of BMPs with legumes may lead to an increased colonization of rhizobia with negative feedback regulation of N fixation. This could result in NO 3 −-N pulse supply, thereby exacerbating plant invasion. Subsequently, a 60-day pot experiment was conducted using Trifolium repens L. as invasive plant and Oxalis corniculata L. as native plant, with 1% or 5% wt BMPs. AMF colonization, BMPs degradation, NO 3 −-N content and pulse supply, rhizobia colonization, relative competitive intensity, replacement diagrams and NO 3 −-N utilization were determined. The mechanism was clarified through heat map and structural equation model. The results reveal the greater the NO 3 −-N consumption by BMPs, the more AMF promoted rhizobia colonization in T. repens , thereby the larger the pulse amplitude of NO 3 −-N supply, then, the higher the NO 3 −-N utilization rate of T. repens. It exacerbates T. repens invasion. This study clarifies effects of BMPs on rhizobia's N fixation, and enriches the evidence on mechanism of BMPs exacerbating plant invasion. [Display omitted] • Biodegradable microplastics (BMPs) trigger feedback regulation of N fixation. • N fixation feedback regulation leads to NO 3 −-N pulse supply. • NO 3 −-N pulse supply caused by BMPs exacerbates the invasion of T.repens. [ABSTRACT FROM AUTHOR]

• Plant biomass increased with increasing number of reseeding species. • Microbial community stability increased with increasing number of reseeding species. • Microbial community stability was positively correlated with plant biomass. • Fungal community stability was the most important variable predicting plant biomass. Forage monoculture and grass-legume mixtures are popular reseeding practices in degraded grasslands. However, the mechanism understanding for the effect of multiple reseeding approaches on soil microbial community and their associated ecosystem functioning remains unclear. Here, we conducted a 3-year field reseeding experiment with eight treatments in a degraded grassland in southern China to test how the link between plant biomass and soil microbial community stability are influenced by plant community structure. Assessments of both above- and below-ground characteristics revealed that reseeding significantly improved plant biomass, soil fertility, and community stability by 53.96 %-126.32 %, 40.74 %-106.91 %, and 13.97 %–33.17 % (P < 0.05) on average, respectively. Furthermore, we found that plant biomass, soil fertility, and microbial community stability increased with increasing number of reseeding species. Dactylis glomerata , Trifolium repens and Lolium perenne mixed-reseeding had significantly higher plant biomass, soil fertility, and microbial community stability than monocultures (P < 0.05). Microbial community stability was positively correlated with plant biomass (P < 0.001). Our field work demonstrates that grass-legume mixtures are beneficial for plant biomass and soil microbes, where stable microbial communities are essential for maintaining ecosystem functions. As such, our findings provide new evidence to guide reseeding practices in degraded southern grasslands and offer novel theoretical insights into plant-soil-microbe interactions under grass-legume mixtures reseeding. [ABSTRACT FROM AUTHOR]

Grass, a low-cost lignocellulosic feedstock with relatively low lignin content, serves as a potential carbon source for microbial processes due to its polymeric sugar content. However, converting carbohydrates into monomeric sugars presents challenges due to complex lignocellulosic matrix. In this study, a mixture of perennial ryegrass and white clover (RG) was pretreated with alkaline before being enzymatically hydrolysed for use as a fermentable sugar source for the oleaginous yeast Metschnikowia pulcherrima. The dilute alkaline pretreatment approach resulted in a 3 times improvement in the conversion of RG, yielding a fermentable sugar concentration of 56.5 g/L. The yeast exhibited a growth yield (Ym/m) of 0.47, producing 23.7 g/L of dry cell weight at 20°C over 140 hours, with a lipid content of 37 % with a similar composition to high oleic palm oil. These findings suggest that RG can be utilised for formulating an oleaginous yeast medium containing the necessary nutrients. [Display omitted] • Sugar production from perennial ryegrass and white clover mixture increased nearly threefold with dilute NaOH pretreatment. • Cultivation in RG hydrolysates exhibited a DCW of 23.7 g/L and FAME profile similar to that observed in a chemical medium. • Neutralisation, rather than washing, for NaOH removal reduced biomass loss during the pretreatment stage by 18.5 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • Elevated CO 2 enhances T. repens ' Pb tolerance, optimizing stress response pathways. • eCO 2 boosts energy efficiency and defence mechanisms, increasing Pb uptake. • Twelve adaptive core microbes identified thriving in altered rhizospheres. • Systems-level integrated omics clarify environment-plant–microbe interactions. • Supports the 'holobiont' concept, emphasizing microbiome-mediated signalling. The increasing atmospheric CO 2 resulting from human activities over the past two centuries, which is projected to persist, has significant implications for plant physiology. However, our predictive understanding of how elevated CO 2 (eCO 2) modifies plant tolerance to metal stress remains limited. In this study, we collected roots and rhizosphere soils from Trifolium repens L. subjected to lead (Pb) stress under ambient and elevated CO 2 conditions, generating transcriptomic data for roots, microbiota data for rhizospheres, and conducting comprehensive multi-omics analyses. Our findings show that eCO 2 reduced the accumulation of Pb-induced reactive oxygen species (ROS) and promoted plant growth by 72% to 402%, as well as increases shoot Pb uptake by 79% compared to ambient CO 2. Additionally, eCO 2 triggers specific defense response in T. repens , elevating the threshold for stress response. We observed a adaptive reconfiguration of transcriptional network that enhances energy efficiency and optimizes photosynthetic product utilization. Notably, eCO 2 induces salicylic acid biosynthesis and activates defense pathways related to redox balance and ROS scavenging processes, thereby enhancing abiotic stress resistance. Through weighted gene co-expression network analysis, our comprehensive investigation reveals a holistic regulatory network encompassing plant traits, gene expression patterns, and bacterial structure potentially linked to metal accumulation as well as tradeoffs between growth and defense in plants under elevated CO 2. These insights shed light on the plant stress responses under elevated CO 2 and while contributing to a broader comprehension of plant-environment interactions. [ABSTRACT FROM AUTHOR]

In New Zealand, intensively managed pasture-based dairy systems rely on binary pastures mostly comprised of Lolium perenne L. and Trifolium repens L.. More frequent and extreme climatic events have been negatively affecting the persistency and production of these pastures, which now present increased seasonality, with marked peaks and troughs of production throughout the year. Diversification of plant species offers a solution to deal with increased seasonality. However, little is known about animal behaviour and dietary preferences of dairy cows grazing diverse pastures. The present study aimed to assess the grazing preferences of dairy cows when unrestrictedly offered binary (L. perenne and T. repens ; Bi) and diverse pastures (L. perenne, Bromus valdivianus Phil. , Dactylis glomerata L. and T. repens ; Mix) subjected to three different leaf regrowth stage (LS) defoliation criteria. Secondarily, the study aimed to determine the main plant-related drivers for any potential animal preference. The treatments were MixLp (defoliated at L. perenne LS), BiLp (defoliated every time MixLp was defoliated), MixBv (defoliated at B. valdivianus LS) and BiBv (defoliated every time MixBv was defoliated), MixDg (defoliated at D. glomerata LS) and BiDg (defoliated every time MixDg was defoliated). Dairy cattle were evaluated over five agricultural seasons. The response variables were grazing time and location, bite rate, animal behavioural activity, pre-grazing herbage mass, undisturbed sward height, lamina:stem ratio, crude protein, metabolisable energy, organic matter digestibility, non-structural carbohydrates, neutral detergent fibre and lignin. Where significant differences were found, binary pastures presented lower sward height and higher non-structural carbohydrate content in comparison to the diverse pastures under the same LS defoliation criteria. However, no significant differences were found in the percentage of time that cows spent grazing both pastures. Season was the greatest contributor to the proportion variation found in all response variables, with values ranging from 47.55 % up to 88.77 %. In winter and spring, cows modulated their grazing behaviour (proportional time spent grazing, ruminating, or idling), investing more time actively grazing pastures under L. perenne LS interval of defoliation (2.5–3.0 LS), the criterion which resulted in shorter grazing rotations. This study allowed us to understand the suitability of diverse pastures from an animal perspective, and highlighted that independent of the pasture type, the positive productive and nutritional effects of defoliation management based on the LS may also extend themselves to positive outcomes in animal preference, interpreted as the percentage of time dairy cows spend grazing rather than ruminating or idling across and within seasons. • Lolium perenne, B. valdivianus, D. glomerata and T. repens comprise a diverse pasture. • No preference was found between binary and diverse pastures under the same leaf regrowth stage (LS) defoliation criteria. • Season was the greatest contributor to the proportion variation in all response variables. • Cows preferred pastures under LS defoliation criteria that resulted in shorter grazing rotations. [ABSTRACT FROM AUTHOR]

• Trifolium repens is a green alternative to toxic corrosion inhibitors. • The inhibitor achieves 98 % inhibition efficiency at 20 ppm in 3.5 % NaCl medium and acts as a mixed-type inhibitor with a strong cathodic effect. • The corrosion inhibition mechanism is driven by physical adsorption of the inhibitor onto the metal surface, following the langmuir adsorption isotherm. • Trifolium repens forms a protective layer which is confirmed by electrochemical and surface analyses. Material degradation is a major issue that has been the subject of intense research and investigation by the scientific community. It has harmful consequences that require serious and careful intervention. However, restrictions on the use of inhibitors containing toxic compounds pose a significant challenge to the implementation of effective corrosion treatments. This has necessitated a continuous search for new and innovative ways to protect against material damage. Plant-derived natural inhibitors offer several advantages, including potent inhibitory effects, lack of toxicity, biodegradability, and environmentally sustainable origins. The purpose of this research was to evaluate the corrosion resistance of API5LX60 carbon steel in a 3.5 % NaCl environment using Trifolium repens as an environmentally friendly inhibitor. The inhibitor extract was analysed using Fourier Transform Infrared (FTIR) spectroscopy. However, gravimetry and electrochemical methods (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)) were used to investigate the corrosion behaviour. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to examine the surface morphology. After testing a range of concentrations in a 3.5 % NaCl medium, the highest level of inhibition (98 %) was obtained at 20 ppm, confirming the mixed action of the inhibitor with predominantly cathodic action. The inhibition mechanism involved physical adsorption on metal surfaces according to the Langmuir model, which enhances the corrosion-inhibiting ability; the extract forms a protective layer that successfully inhibits corrosion, as confirmed through electrochemical and surface analysis. These results demonstrate that the extract acts as a potent anticorrosive agent. [Display omitted] [ABSTRACT FROM AUTHOR]

• We first identified 134 1R-MYB members in white clover (Trifolium repens L.) by genome-wide analysis. • Five Tr1R-MYB genes showed different expression patterns under drought stress. • TrMYB130 negatively regulates drought resistance of arabidopsis (Arabidopsis thaliana L.). White clover (Trifolium repens L.) is a high-quality leguminous forage, but its short rooting habit, poor transpiration tolerance, and drought tolerance, have become a key factor restricting its growth and cultivation. 1R-MYB transcription factors (TFs) are a significant subfamily of TFs in plants, playing a vital role in regulating plant responses to drought stress, however, knowledge about the role of 1R-MYB transcription factors in white clover is still limited. We identified 134 1R-MYB members, which were unevenly designated onto 16 chromosomes and divided phylogenetically into five subgroups. The members of the same subgroup had conserved motifs. Collinearity analysis revealed that segmental and tandem duplications significantly contributed to the expansion of the Tr1R-MYBs. Tr1R-MYBs promoter region enriched with potential drought cis -acting regulatory elements. The RT-qPCR results show that the five Tr1R-MYB genes (TrMYB41 , TrMYB49 , TrMYB94 , TrMYB125 , TrMYB130) have a certain degree of response under drought stress conditions but exhibited different expression profiles. Furthermore, subcellular localization analysis showed that the TrMYB130 protein is primarily located in the nucleus. Overexpression of this protein in transgenic Arabidopsis (Arabidopsis thaliana L.) was found to impair drought tolerance. Our findings will establish a basis for deeper investigation into the characteristics and functions of 1R-MYB TFs, as well as for employing genetic engineering techniques to improve white clover. [ABSTRACT FROM AUTHOR]

Reducing nitrate leaching and addressing water quality concerns is a challenge in grazed pasture systems globally. Recent single soil, single region studies have indicated that the inclusion of ribwort plantain (Plantago lanceolate L.) in pasture swards can reduce nitrate-N (NO 3 --N) leaching. The present two-year five-soil lysimeter study tests the potential of ribwort plantain inclusion in grass-clover (Lolium perenne L. and Trifolium repens L.) swards to reduce NO 3 --N leaching across a range of soils. The inclusion of plantain at 30 % reduced NO 3 --N loss in free-draining soils by 7–59 kg NO 3 --N ha−1 (by 32–74 %, mean 56 %) in year one and by 12–54 kg NO 3 --N ha−1 (93–99 %, mean 96 %) in year two. In poorly drained soils the loss reduction ranged from 2 to 6 kg NO 3 --N ha−1 (3–10 %, mean 6 %) in year one and by 29–36 kg NO 3 --N ha−1 (97–98 %, mean 97 %) in year two. Increasing plantain inclusion to 50 % reduced NO 3 --N loss in the free-draining soils by 11–91 kg NO 3 --N ha−1 (50–95 %, mean 78 %) in year one and by 13–56 kg NO 3 --N ha−1 (97–98 %, mean 98 %) in year two. In poorly drained soils the NO 3 --N loss reduction ranged from 12 to 15 kg NO 3 --N ha−1 (18–24 %, mean 21 %) in year one and by 29–36 kg NO 3 --N ha−1 (98 %) in year two. Plantain inclusion reduced drainage water volume by 1–16 %, potentially contributing to nitrate-N loss mitigation. Plantain inclusion reduced drinking water NO 3 --N maximum allowable concentration (MAC) exceedances in leachate from 28 in grass-clover to seven with 30 % plantain inclusion and four with 50 % plantain inclusion. Much of the benefit of plantain inclusion was achieved at the 30 % plantain rate in grass-clover pastures. Overall, across a broad range of soils, the inclusion of plantain in grass-clover swards was shown to be an effective tool for reducing nitrate-leaching losses in pasture systems. [Display omitted] • Reducing nitrate leaching to waterbodies is a universal challenge in modern agricultural systems. • Plantain inclusion reduced nitrate-N leaching by 32–99 % in free-draining soils, by 82 % on average. • Including plantain mitigated 3–98 % nitrate-N leaching in poorly drained soils, by 56 % on average. • Plantain inclusion reduced MAC exceedances from 28 times to 7 with 30 % and 4 with 50 % plantain. • Plantain is a promising tool for reducing nitrate leaching in pasture across a range of soils. [ABSTRACT FROM AUTHOR]

In this research, a compact and lightweight Time Domain (TD)-OCT for plant measurements is developed. The leaves (Orchis graminifolia and Trifolium repens) were immersed in two kinds of liquids to make them transparent, expand the depth, and homogenize the signals of OCT images. Optical clearing using a chlorine-based cleaner reduces the internal signal and increases the measurement depth by removing the internal structures. Since chlorine-based cleaners enhance the vein signal, this liquid is useful for diagnosing the disease that occurs in veins. Optical clearing of plant-clearing agents can detect layer changes with internal refractive index changes by reducing light scattering. Since the plant-clearing agent makes the OCT image uniform, this liquid is useful for diagnosing the small changes inside the tissue due to the disease. Applying transparency liquids to the plant field measurement can quantitatively evaluate changes in internal structure and refractive index due to disease or environment. The proposed method of the combination of compact OCT and optical clearing can obtain small changes in the veins, palisade tissue, and spongy tissue. • Plant leaf evaluation method is proposed using portable OCT and optical clearing. • Optical clearing restricts internal scattering which improves penetration of light. • The plant-clearing agent makes the attenuation inside the leaves constant. • Chlorine-based cleaner enhances OCT vein signals of leaves. [ABSTRACT FROM AUTHOR]

Portable Accumulation Chambers (PAC) represent an important tool for quantifying greenhouse gases (GHG) in small ruminants. The objectives of the study were to evaluate to reduce the PAC time evaluation in sheep without compromising the GHG, methane (CH 4) and carbon dioxide (CO 2) measurements and to evaluate the PAC methodology, considering the variability of gaseous emissions in the day. Four times the animals spent in the PAC (10, 20, 30 and 40 minutes) and two collection times during the day (morning and afternoon) were tested for two consecutive days. The sheep used in the study came from a field experiment where they were subjected to different grazing feeding systems (only Italian ryegrass, Italian ryegrass in a mixture of legumes (Persian clover (Trifolium resupinatum L.) and White clover (Trifolium repens L.)) pasture and lambs grazing Italian ryegrass and consuming an energetic supplement (RyeG + Sup)). The gas samples collected at PAC were analyzed for CH 4 and CO 2 concentration on a gas chromatograph. There was no interaction in CH 4 and CO 2 measurements between times, shifts and grazing feeding systems (p > 0.05). CH 4 emission between times did not differ (p > 0.05), while CO 2 emissions were higher in the first 10 minutes of measurement and lower in the remaining times, fitting the non-linear regression model, with a reduction until 27.7 minutes. In relation to shifts, there was a difference for CH 4 (p < 0.01), and CO 2 (p = 0.01) with the highest emissions of CH 4 (21.7 ± 4.3 g/day) and CO 2 (1282 ± 332 g/day) found in the afternoon. The results of this study indicate that 27.7 minutes of sheep staying in the PAC is enough to evaluate CH 4 and CO 2 emissions and to improve the estimate of the gas emissions, evaluations should be carried out in the morning and afternoon. [Display omitted] • It is important to measure greenhouse gases (GHG) in sheep. • Portable Accumulation Chambers (PAC) can measure GHG emissions in sheep. • The length of stay in the PAC and the day shifts must be considered for measurements. • Sheep must remain inside the PAC to measure gases for at least 27.7 minutes. • Gas emissions measurements by sheep must be carried out in morning and afternoon. [ABSTRACT FROM AUTHOR]

Industrialization-driven surface ozone (O 3) pollution significantly impairs plant growth. This study evaluates the effectiveness of exogenous protectants [3 mg L⁻1 abscisic acid (ABA), 400 mg L⁻1 ethylenediurea (EDU), and 80 mg L⁻1 spermidine (Spd)] on Trifolium repens subjected to O 3 stress in open-top chambers, focusing on plant growth and dynamics of culturable endophytic fungal communities. Results indicate that O 3 exposure adversely affects photosynthesis, reducing root biomass and altering root structure, which further impacts the ability of plant to absorb essential nutrients such as potassium (K), magnesium (Mg), and zinc (Zn). Conversely, the application of ABA, EDU, and Spd significantly enhanced total biomass and chlorophyll content in T. repens. Specifically, ABA and Spd significantly improved root length, root surface area, and root volume, while EDU effectively reduced leaves' malondialdehyde levels, indicating decreased oxidative stress. Moreover, ABA and Spd treatments significantly increased leaf endophytic fungal diversity, while root fungal abundance declined. The relative abundance of Alternaria in leaves was substantially reduced by these treatments, which correlated with enhanced chlorophyll content and photosynthesis. Concurrently, EDU and Spd treatments increased the abundance of Plectosphaerella , enhance the absorption of K, Ca, and Mg. In roots, ABA treatment increased the abundance of Paecilomyces , while Spd treatment enhanced the presence of Stemphylium , linked to improved nitrogen (N), phosphorus (P), and K uptake. These findings suggest that specific symbiotic fungi mitigate O 3 -induced stress by enhancing nutrient absorption, promoting growth. This study highlights the potential of exogenous protectants to enhance plant resilience against O 3 pollution through modulating interactions with endophytic fungal communities. [Display omitted] • Elevated O 3 impairs T. repens growth by reducting photosynthesis. • Exogenous protectants enhance biomass and especially promote root growth of T. repens under O 3 stress. • Exogenous protectants alter fungi community and affect nutrient uptake of T. repens. [ABSTRACT FROM AUTHOR]

Anthocyanins and proanthocyanidins (PAs) are important secondary metabolites in plants, high contents of which are an important goal for quality breeding of white clover (Trifolium repens). However, the involvement of glutathione S-transferase (GST) in the transport of anthocyanins and PAs remains unexplored in white clover. This study identified 153 different TrGSTs in white clover. At the transcriptional level, compared to other TrGSTFs, TrGSTF10 and TrGSTF15 are highly expressed in the 'Purple' white clover, and they may work with the anthocyanin biosynthesis structural genes CHS and CHI to contribute to pigment buildup in white clover. Subcellular localization confirmed that TrGSTF10 and TrGSTF15 are located in the cytoplasm. Additionally, molecular docking experiments showed that TrGSTF10 and TrGSTF15 have similar binding affinity with two flavonoid monomers. Overexpression of TrGSTF15 complemented the deficiency of anthocyanin coloring and PA accumulation in the Arabidopsis tt19 mutant. The initial findings of this research indicate that TrGSTF15 encodes an important transporter of anthocyanin and PA in white clover, thus providing a new perspective for the further exploration of related transport and regulatory mechanisms. • 153 TrGSTs were identified in Trifolium repens. • TrGSTF10/TrGSTF15 may be associated with the transport of anthocyanins and PAs. • TrGSTF10 and TrGSTF15 are located in the cytoplasm and have similar binding affinity with flavonoid monomers. • TrGSTF15 complemented the phenotype of Arabidopsis tt19 mutant. [ABSTRACT FROM AUTHOR]

Parasitic plants can mediate soil conditioning by invasive and native host plant species, but how this may affect the competitive ability of these plants when they later grow in the conditioned soil has never been tested. This study tested whether soil conditioned by three invasive and three native plant species, either parasitized by a holoparasitic plant Cuscuta gronovii or non-parasitized, would differentially affect the competitive ability of those species. In the first phase, field soil was conditioned using individuals of the six host plant species, either parasitized or non-parasitized. The second phase tested the competitive ability of individuals of those invasive and native plants by growing them alone or in competition with Trifolium repens in either live or sterilized conditioned soil. In the soil conditioning phase, parasitism significantly increased soil NH 4 +-N concentration by 17 %, decreased soil organic carbon by 18 %, and marginally decreased microbial biomass carbon concentration by 21 %. In the soil feedback phase, native plant species generally had higher competitive ability in soil that was conditioned by parasitized plants than in soil that was conditioned by non-parasitized plants. In contrast, soil conditioned by parasitized plants had only a marginal effect on the competitve ability of invasive plants, compared to growth in soil conditioned by non-parasitized plants. Native plants had greater competitive ability in soil with lower soil organic carbon, while invasive plants had greater competitive ability in soil with higher microbial biomass carbon and lower NH 4 +-N. These findings demonstrate that parasitism by C. gronovii mediated different soil legacy effects of invasive and native plant species through changes in soil organic carbon, soil NH 4 +-N, and microbial biomass carbon levels. Broadly, these results suggest that parasitic plants may limit invasions by alien plant species and promote the co-existence of the invaders with native plant species through soil-mediated legacy effects. • Parasitism increased soil NH 4 +-N, decreased SOC, and marginally decreased MBC concentrations. • Parasitism increased competitive ability of native plant through soil legacy effect. • Parasitism marginally decreased competitive ability of invaders through soil legacy effect. [ABSTRACT FROM AUTHOR]

Crop rotation and diversification can alleviate the high nitrate leaching associated with maize (Zea mays L.) monoculture, without reducing yields. Prior research focused on maize-legume/cereal rotations, with limited exploration of rotations with industrial crops destined for biorefining. In 2012, four-year rotation systems were established on sandy soil in Denmark, consisting of maize, hemp (Cannabis sativa L.), beet (Beta vulgaris L.), and triticale (Triticosecale), organized into four sequences to ensure the occurrence of each crop in each year. The fallow periods in the rotations were covered with "secondary crops"- winter rye (Secale cereale L.), winter rape (Brassica napus L.), or grass-clover (Festuca rubra L. – Trifolium repens L.). Over two rotation cycles (eight years), we assessed the aboveground biomass dry matter, biomass nitrogen (N) uptake, and their stabilities of maize in rotations versus monoculture, alongside quantifications of nitrate leaching, and soil carbon (C) and N stocks up to 100 cm deep. In the first cycle, the aboveground biomass of maize in rotation (15.5 Mg ha−1) was 7% significantly lower than that in monoculture (16.6 Mg ha−1), but this difference disappeared in the second cycle (17 versus 16.5 Mg ha−1). The maize biomass N uptake in rotation (194.5 kg ha−1) was similar to that in monoculture (196.6 kg ha−1) in the first cycle and was significantly higher by 8% in the second cycle (195.5 versus 165.7 kg ha−1). Nitrate leaching varied interannually with precipitation and secondary crops. Higher rainfall increased nitrate leaching for both systems in cold months, while rotations had more leaching after irrigation in dry periods. Initially, diverse rotation halved nitrate leaching compared to monoculture, but increased at the onset of the second cycle when the preceding winter rape did not survive in the winter. Winter rye following maize reduced nitrate leaching, except when the preceding crop was grass-clover or poorly thriving winter rape. During the whole period, the rotation system increased soil C and N stocks at 0–100 cm depth. This study highlights the environmental and yield benefits of diversifying maize rotations, and the crucial role of secondary crop management to optimize maize rotation strategies. • Maize biomass in diverse rotation increased in the second, not first rotation cycle. • Maize biomass N uptake also effectively increased in the second rotation cycle. • Rotation increased soil C and N stocks at a depth of 1 m versus monoculture. • Secondary crops affected yearly NO 3 - leaching, with grass-clover's negative impact. [ABSTRACT FROM AUTHOR]

Pollen abnormalities frequency of Scots pine and pollen sterility of white clover, common columbine, and greater celandine growing in the Bryansk and Gomel' regions radioactively contaminated after the accident at the Chernobyl nuclear power plant (NPP) were assessed. The frequency of abnormal pine pollen at the most contaminated plots significantly exceeded the control level and positively correlated with the total absorbed dose and the absorbed dose from β -radiation. No sustainable significant changes in pollen sterility of the herbaceous plants studied were found in the exclusion zone of the Chernobyl NPP. • Pine abnormal pollen frequency, in some cases, increased near the Chernobyl NPP. • Frequency of pine abnormal pollen positively correlated with the absorbed dose. • Radiation levels near the ChNPP did not induce steady changes in pollen sterility. [ABSTRACT FROM AUTHOR]

Plants can affect N 2 O emissions by enhancing nitrogen (N) uptake and other below-ground interactions. However, the specific effect of the root systems of different plant species on the production and accumulation of N 2 O within the soil profile remain largely unknown. The aim of this study was to investigate how plant species from different functional groups, their productivity and root traits affect N 2 O emissions and N 2 O concentrations within the soil profile in a fertilised grassland. We conducted a field experiment with two grasses (Phleum pratense , Lolium perenne), two legumes (Trifolium repens , Trifolium pratense), two forbs (Cichorium intybus , Plantago lanceolata), and the six-species mixture in a fertilised grassland. The effects of these plant communities on N-cycling processes were then assessed through the measurement of above- and below-ground plant traits, plant productivity, soil nutrient availability, N 2 O emissions and its distribution in the soil profile. We found that C. intybus and P. pratense had the lowest N 2 O emissions from the soil, which was mainly related to higher root biomass. The six-species mixture also showed lower N 2 O emissions compared to L. perenne monoculture which was explained by complementary effects between the different plant species. We did not find a relationship between N 2 O emission and its concentration in the soil profile. Higher specific root length and root length density coincided with higher N 2 O concentrations at 10–20 and 20–30 cm soil depths. Since these two traits have been previously linked to reductions in N 2 O emissions emitted from the soil, our results show that the relationships between root traits and N 2 O emissions may not be reflected down in the soil profile. Overall, this study underscores the often-neglected importance of root traits for N-cycling and emphasises the need to better understand how root traits modify N 2 O consumption within the soil profile to design more sustainable grasslands. • C. intybus and P. pratense decreased N 2 O emissions due to higher root biomass. • Mixture lower N 2 O emissions compared to L. perenne due to complementary effects. • There is no relationship between N 2 O emission and its concentration in the soil profile. • Higher root traits coincided with higher N 2 O concentrations in the soil profile. [ABSTRACT FROM AUTHOR]

Understanding the determinants of early invasion resistance is a major challenge for designing plant communities that efficiently repel invaders. Recent evidence highlighted the significant role of priority effects in early community assembly as they affect species composition, structure and functional properties, but the consequences of native community assembly history on the success of subsequent invasions has not been elucidated yet. In a greenhouse experiment, we investigated how (1) the identity of the first native colonizing species (one of two grasses: Dactylis glomerata and Lolium perenne , or two legumes: Onobrychis viciifolia and Trifolium repens), each introduced four weeks before the rest of the native community, and (2) timing of species establishment (synchronous vs. sequential sowing), influenced early establishment success of Ambrosia artemisiifolia , an annual noxious weed in Europe. First colonizer identity and establishment timing both affected early biomass production and composition of the community, and had implications for A. artemisiifolia early invasion success. Invasion success decreased when all native individuals were sown simultaneously, quickly generating a high biomass production, while it increased when the productive N-fixing legume T. repens was sown first. These findings support that native species assembly history matters to invasion resistance in the early growth stages, thus opening the way to more effective invasive species management strategies in restoration. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of cow genotype and parity on dry matter intake (DMI) and production efficiencies in pasture-based systems. Three dairy cow genotypes were evaluated over 3 yr; 40 Holstein-Friesian (HF), 40 Jersey × HF (JEX), and 40 Norwegian Red × JEX (3WAY) each year, with each genotype grazed in equal numbers on 1 of 4 grazing treatments in a 2 × 2 factorial arrangement of treatments [diploid or tetraploid perennial ryegrass (Lolium perenne L.) with or without white clover (Trifolium repens L.)]. A total of 208 individual cows were used during the experiment. The effect of parity (lactation 1, 2, and 3+) was also evaluated. Individual DMI was estimated 8 times during the study, 3 times in 2015 and in 2017, and twice in 2016, using the n-alkane technique. Days in milk at each DMI measurement period were 64, 110, and 189, corresponding to spring, summer, and autumn. Measures of milk production efficiency calculated were total DMI/100 kg of body weight (BW), milk solids (kg fat + protein; MSo)/100 kg of BW, solids-corrected milk (SCM)/100 kg of BW, and unité fourragère lait (net energy requirements for lactation equivalent of 1 kg of standard air-dry barley; UFL) available for standard (4.0% fat and 3.1% protein content) milk production after accounting for maintenance. During the DMI measurement periods HF had a greater milk yield (23.2 kg/cow per d) compared with JEX and 3WAY (22.0 and 21.9 kg/cow per d, respectively) but there was no difference in MSo yield. Holstein-Friesian and JEX, and JEX and 3WAY had similar DMI, but HF had greater total DMI than 3WAY (DMI was 17.2, 17.0, and 16.7 kg/cow per d for HF, JEX, and 3WAY, respectively). Jersey × Holstein-Friesian cows were the most efficient for total DMI/100 kg of BW, SCM/100 kg of BW, and MSo/100 kg of BW (3.63, 4.96, and 0.39 kg/kg of BW) compared with HF (3.36, 4.51, and 0.35 kg/kg of BW) and 3WAY (3.45, 4.63, and 0.37 kg/kg of BW), respectively. Unité fourragère lait available for standard milk production after accounting for maintenance was not different among genotypes. As expected, DMI differed significantly among parities with greater parity cows having higher DMI and subsequently higher milk and MSo yield. Although all 3 genotypes achieved high levels of DMI and production efficiency, JEX achieved the highest production efficiency. Some of the efficiency gains (SCM/100 kg of BW, MSo/100 kg of BW, and total DMI/100 kg of BW) achieved with JEX decreased when the third breed (Norwegian Red) was introduced. [ABSTRACT FROM AUTHOR]

The invasion of alien plant and the pollution caused by soil microplastics have emerged as significant ecological threats. Recent studies have demonstrated aggravating effect of non-biodegradable microplastics on plant invasion. However, the impact of biodegradable microplastics (BMPs) on plant invasion remains unclear. Therefore, it is imperative to explore the impact of BMPs on plant invasion. In this study, a 30-day potting experiment with Trifolium repens L. (an invasive plant) and Oxalis corniculata L. (a native plant) was conducted to evaluate the influence of BMPs on T. repens 's invasion. The findings revealed that BMPs results in a reduction in available N and P contents, thereby facilitating the colonization of arbuscular mycorrhizal fungi on T. repens 's roots. Consequently, T. repens adjusted its N and P foraging strategy by increasing P absorption ratio, and enhancing the accumulation of N and P in leaves. This ultimately led to the decrease of relative neighbor effect index of T. repens , indicating an aggravated invasion by T. repens. This study significantly enhances and expands the understanding of mechanisms by which microplastics aggravate plant invasion. [Display omitted] ● Biodegradable microplastics (BMPs) aggravate invasion of Trifolium repens L. ● BMPs aggravate the colonization rate of AMF in invasive plant. ● Invasive plants' absorption and utilization of N and P have been altered by BMPs. [ABSTRACT FROM AUTHOR]

There is a pressing need to support farmers' decisions on grassland renovation, based on sound scientific evidence regarding its effects on productivity, herbage quality and soil organic carbon stocks. To quantify these effects a long-term experiment with grass/white clover swards was set up at the Lindhof research farm in Northern Germany in 1995. Treatments included control plots of undisturbed grassland as well as 10 grassland renovations starting after 10 (2005) years and repeated on different plots 10 times until 2019, and without and with addition of slurry (equivalent to 240 kg N ha−1 yr−1). Grassland renovation resulted in a significant drop in biomass production in the first year after renovation, and the slightly higher yields in the third year after renovation could not compensate for this drop. Yields from the year of renovation to three years afterwards were generally lower, with average reductions over the 4-year periods of 2600 kg DM ha−1 for the treatments without slurry and 1500 kg DM ha−1 for the slurry treatments. Differences in herbage quality between permanent and renovated grassland were negligible and generally not statistically significant. The soil organic carbon showed a rapid and significant drop in the year of renovation, followed by a gradual increase. Without slurry application, the initial levels of soil organic carbon stocks could not be reached even after a period of 18 years following renovation, and with slurry application, it took about 8–10 years. Deep ploughing to a depth of 30 cm did not increase the SOC stocks compared with the undisturbed permanent grasslands, suggesting that the topsoil has not reached the carbon saturation level. We conclude that maintaining productivity of permanent grassland without renovation measures is a promising way towards yield stability and natural climate solutions. • Grassland (grass/white clover) renovation resulted in a significant yield drop in the first year. • Slightly higher yields 3 years after renovation did not compensate for yield losses. • SOC dropped significantly after renovation, followed by a gradual increase. • With fertiliser, SOC stocks in renovated grasslands can be recovered after a decade • Deeper ploughing did not increase SOC stocks, likely due to a C saturation deficit. [ABSTRACT FROM AUTHOR]

White clover (Trifolium repens L.) is a herbaceous, perennial plant that has become one of the most widely distributed legumes in the world. It is cultivated in a large area in China, mainly for animal husbandry feed, artificial grassland, garden greening and ecological construction. In 2022, leaf spot disease was observed on white clover in China's Sichuan province, and the strain was isolated. The pathogenicity of the isolates was confirmed using Koch's postulates. The fungus was/were red on PDA, and two types of conidia were observed after 6 days of cultivation on straw juice medium. The pathogen was identified as Fusarium graminearum by the amplification of part of the ITS and TEF-α genes and by phylogenetic analysis. Currently, this is the first report to indicate that the causal agent of leaf spot disease on white clover is F. graminearum. • The first report of Fusarium graminearum Causing Leaf Spot of white clover (Trifolium repens) in China. • Fusarium graminearum was identified by ITS and TEF1-α genes. • This can be helpful for the control of white clover leaf spot. [ABSTRACT FROM AUTHOR]

Globally, the soils underlying managed grasslands are an important reservoir of carbon (C), with the management of the land strongly influencing whether the soils gain, lose or maintain C. Further, improved grassland management, such as rotational grazing and increased sward diversity, are widely promoted to increase soil C sequestration despite limited evidence. Using data from New Zealand's grazed dairy grasslands, we examined the effect of management practices on C stocks through measurement of the net ecosystem C balance (NECB) across 68 site-years. Management practices tested included year-round rotational grazing, differing pasture sward composition, irrigation, periodic supplemental feed cropping and pasture renewal. Excluding years where supplemental feed cropping occurred, the mean (±95% confidence interval) NECB was −12 ± 30 g C m−2 y−1 (65 site-years; the negative value represents C loss), indicating the soil C stocks of these ecosystems were likely near steady-state. The processes of pasture renewal and the transition between pasture and crops resulted in reduced C inputs from photosynthesis of between −232 and −94 g C m−2. This reduced C input was partially overcome with the application of effluent or manure at the time of cultivation where applied. There was no difference in NECB between irrigated (−26 ± 114 g C m−2 y−1) and non-irrigated (−19 ± 198 g C m−2 y−1) pastures. In general, conventional ryegrass/white clover pastures were more beneficial for C stocks than alternative pasture species and mixes. Periodic cropping for supplemental feed resulted in C losses, with the magnitude depending on crop type and management, although data were limited to three site-years. [Display omitted] • Carbon (C) balances of grazed flat-land dairy pastures were near steady-state. • C loss during pasture and crop establishment depended on time to net CO 2 uptake. • Ryegrass/white clover pastures were better for C stocks than alternative swards. • Irrigation had inconclusive effects on C balance and may depend on pasture species. [ABSTRACT FROM AUTHOR]

The objective of this systems-scale study was to investigate grazing season timeframes on pasture and milk production and on milk processability of dairy systems with compact spring-calving dairy cows grazing white clover (Trifolium repens L.) based grassland. Fifty-four primiparous and multiparous Holstein-Friesian dairy cows were used in a one-factor study with 3 systems (n = 18) and repeated over 2 yr (2008/09 and 2009/10). The 3 systems were: early spring calving with annual fertilizer N input of 100 kg·ha−1 applied in spring (ES100N; 2.1 cows·ha−1; grazing February to November), early spring calving without fertilizer N (ES0N; 1.6 cows·ha−1; grazing February to November) and late spring calving without fertilizer N (LS0N; 1.53 cows·ha−1; grazing April to January). Annual pasture production was affected by an interaction between grazing system and year: Mean annual pasture yields for 2008 and 2009 were ES100N; 10.35 and 9.88, ES0N; 8.88 and 8.63, LS0N; 9.18 and 10.31 t of dry matter (DM)·ha−1 (SEM 0.39). LS0N had higher pasture DM yield in 2009 due to higher clover DM production and biological N fixation compared with the other systems. Clover stolon and root mass in the following February was correlated with stolon and root mass in the previous November with 64% of stolon mass present on LS0N in February (R2 = 0.84). There were no detectable differences in per-lactation milk yield (6,335 kg·cow−1), fat, protein and lactose yields (271, 226, 297 kg·cow−1, respectively), cow liveweight (585 kg) or body condition score (3.02). Although winter grazing favored subsequent clover DM production, biological N fixation and pasture DM production, delaying calving date in spring and extending lactation into the following winter led to inefficient use of this pasture by the grazing herd and lowered the quality of late-lactation milk for processing purposes. Hence, a mean calving date in mid- to late-February is recommended for zero-fertilizer N input clover-based grassland. [ABSTRACT FROM AUTHOR]

S-adenosylmethionine decarboxylase (SAMDC) mediates the biosynthesis of polyamines (PAs) and plays a positive role in plants' response to adversity stress tolerance. In this study, we isolated a SAMDC gene from white clover, which is located in mitochondria. It was strongly induced when white clover exposed to drought (15% PEG6000), salinity (200 mM NaCl), 20 μM spermidine, 100 μM abscisic acid, and 10 mM H 2 O 2 , especially in leaves. The INVSc1 yeast introduced with TrSAMDC1 had tolerance to drought, salt, and oxidative stress. Overexpression of TrSAMDC1 in Arabidopsis showed higher fresh weight and dry weight under drought and salt treatment and without growth inhibition under normal conditions. Leaf senescence induced by drought and saline was further delayed in transgenic plants, regardless of cultivation in 1/2 MS medium and soil. During drought and salt stress, transgenic plants exhibited a significant increase in relative water content, maximum photosynthesis efficiency (Fv/Fm), performance index on the absorption basis (PI ABS), activities of antioxidant protective enzymes such as SOD, POD, CAT, and APX, and a significant decrease in accumulation of MDA and H 2 O 2 as compared to the WT. The concentrations of total PAs, putrescine, spermidine, and spermidine in transgenic lines were higher in transgenic plants than in WT under normal and drought conditions. These results suggested that TrSAMDC1 could effectively mitigate abiotic stresses without the expense of production and be a potential candidate gene for improving the drought and salt resistance of crops. • TrSAMDC1 located in mitochondria positively respond to drought, salt, Spm, ABA, and H 2 O 2 treatments in white clover. • TrSAMDC1 conferred drought, salt and oxidative tolerance in transgenic yeasts. • Overexpression of TrSAMDC1 enhanced drought and salt resistance in Arabidopsis. • Overexpression of TrSAMDC1 improved endogenous PAs titers and antioxidant capacities. [ABSTRACT FROM AUTHOR]

White clover (WC) offers an alternative source of nitrogen (N) for pasture-based systems. Substituting energy- and carbon-intensive synthetic N fertilizers with N derived from biological fixation by WC has been highlighted as a promising environmental mitigation strategy through the omission of emissions, pollutants, and energy usage during the production and application of synthetic fertilizer. Therefore, the objective was to investigate the effect of the inclusion of WC in perennial ryegrass (PRG) swards on the environmental impact of pasture-based dairy systems. Cradle-to-farm gate life cycle assessment of 3 pasture-based dairy systems were conducted: (1) a PRG–WC sward receiving 150 kg of N/ha per year (CL150), (2) a PRG–WC sward receiving 250 kg of N/ha per year (CL250), and (3) a PRG-only sward receiving 250 kg of N/ha per year (GR250). A dairy environmental model was updated with country-specific N excretion equations and recently developed N 2 O, NH 3 , and NO 3 − emission factors. The environmental impact categories assessed were global warming potential, nonrenewable energy, acidification potential, and eutrophication potential (marine and freshwater). Impact categories were expressed using 2 functional units: per hectare and per metric tonne of fat- and protein-corrected milk. The GR250 system had the lowest milk production and highest global warming potential, nonrenewable energy, and acidification potential per tonne of fat- and protein-corrected milk for all systems. The CL250 system produced the most milk and had the highest environmental impact across all categories when expressed on an area basis. It also had the highest marine eutrophication potential for both functional units. The impact category freshwater eutrophication potential did not differ across the 3 systems. The CL150 system had the lowest environmental impact across all categories and functional units. This life cycle assessment study demonstrates that the substitution of synthetic N fertilizer with atmospheric N fixed by WC has potential to reduce the environmental impact of intensive pasture-based dairy systems in temperate regions, not only through improvement in animal performance but also through the reduction in total emissions and pollutants contributing to the environmental indicators assessed. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of perennial ryegrass (Lolium perenne L.; PRG) ploidy and white clover (Trifolium repens L.) inclusion on milk production, dry matter intake (DMI), and milk production efficiencies. Four separate grazing treatments were evaluated: tetraploid PRG only, diploid PRG only, tetraploid PRG with white clover, and diploid PRG with white clover. Individual DMI was estimated 8 times during the study (3 times in 2015, 2 times in 2016, and 3 times in 2017) using the n -alkane technique. Cows were, on average, 64, 110, and 189 d in milk during the DMI measurement period, corresponding to spring, summer, and autumn, respectively. Measures of milk production efficiency were total DMI/100 kg of body weight (BW), milk solids (kg of fat + protein; MSo)/100 kg of BW, solids-corrected milk/100 kg of BW, and MSo/kg of total DMI. Perennial ryegrass ploidy had no effect on DMI; however, a significant increase in DMI (+0.5 kg/cow per day) was observed from cows grazing PRG-white clover swards compared with PRG-only swards. Sward white clover content influenced DMI as there was no increase in DMI in spring (9% sward white cover content), whereas DMI was greater in summer and autumn for cows grazing PRG-white clover swards (+0.8 kg/cow per day) compared with PRG-only swards (14 and 23% sward white clover content, respectively). The greater DMI of cows grazing PRG-white clover swards led to increased milk (+1.3 kg/cow per day) and MSo (+0.10 kg/cow per day) yields. Cows grazing PRG-white clover swards were also more efficient for total DMI/100 kg of BW, solids-corrected milk/100 kg of BW, and MSo/100 kg of BW compared with cows grazing PRG-only swards due to their similar BW but higher milk and MSo yields. The results highlight the potential of PRG-white clover swards to increase DMI at grazing and to improve milk production efficiency in pasture-based systems. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the economic performance of 2 sward types [perennial ryegrass (PRG; Lolium perenne L.) sown with or without white clover (Trifolium repens L.)] grazed by 3 cow genotypes. Physical performance data were collected from a 4-yr systems experiment based at Clonakilty Agricultural College, Clonakilty, Co. Cork, Ireland. The experiment compared 2 sward types (PRG-only swards and PRG–white clover swards), with each sward type being grazed by cows from 3 genotypes [Holstein-Friesian (HF), Jersey × HF (JEX), and Norwegian Red × JEX (3-way)]. All systems were stocked at 2.75 cows/ha with fixed fertilizer applications and concentrate supplementation. The data supplied 6 production systems (2 sward types × 3 cow genotypes). The production systems were modeled using the Moorepark Dairy Systems Model (stochastic budgetary simulation model) under 2 scenarios, one in which land area was fixed and one in which cow numbers were fixed. The analysis was completed across a range of milk prices, calf prices, and reseeding programs. The analysis showed that in the fixed-land scenario with a milk price of €0.29/L, adding white clover to PRG swards increased profitability by €305/ha. In the same fixed-land scenario, JEX cows were most profitable (€2,606/ha), followed by 3-way (€2,492/ha) and HF (€2,468/ha) cows. In the fixed-cow scenario, net profit per cow was €128 greater for PRG–white clover swards compared with PRG-only swards. In this scenario, JEX was the most profitable per cow (€877), followed by HF (€855) and 3-way (€831). The system that produced the highest net profit was JEX cows grazing PRG–white clover swards (€2,751/ha). Regardless of reseeding frequency or variations in calf value, JEX cows grazing PRG–white clover swards consistently produced the highest net profit per hectare. [ABSTRACT FROM AUTHOR]

Bees are declining, which is worrisome since they both have intrinsic conservation value and play a major role as pollinators in both natural and managed ecosystems. Land use change and lack of suitable habitats are often suggested as driving forces of bee decline. To propose mitigation measures to halt bee decline, it is important to understand how land use relates to bee abundance and diversity, and to explore consequences for their provision of pollination services. White clover, Trifolium repens , is an outcrossing mass-flowering crop, which could serve as an abundant, although ephemeral, food resource for bees. We investigated how the bee community in 39 fields of white clover grown for seed, related to local field management (organic, conventional without insecticides and conventional with insecticides) and landscape context (proportion semi-natural land), and how this pollinator community related to white clover seed set. The honey bee, Apis mellifera , was the most commonly observed bee species, and two generalist bumble bee species, Bombus terrestris and B. lapidarius , were the subsequently most common. We observed fewer non- Apis bees, and a lower bee species richness in organic white clover seed fields compared to conventional fields independent of insecticide treatment. Bee species richness in both conventional and organic fields were positively related to the proportion of semi-natural land in the landscape, likely because of a larger species pool in such landscapes. Initial seed set in immature inflorescences was positively related to bee abundance, whereas final seed set in mature inflorescences was unrelated to bee abundance, possibly as a consequence of seed-eating weevils consuming a large proportion of the seeds. We conclude that both bee visitation and seed set in white clover benefit from conventional management and that landscapes rich in semi-natural habitats will make future crop production more resilient. The observed positive relationship between bee abundance and initial seed set suggests that if we can mitigate pest impacts and increase bee abundance in clover seed fields, the final seed yield can be increased. Thus, bee decline should be considered and mitigated both to maintain biodiversity in general and for crop seed production specifically. • Lower (non-Apis) bee abundance and species richness in organic white clover fields • Bee species richness positively related to the proportion of semi-natural land • Initial seed set in immature inflorescences positively related to bee abundance • Final seed set was unrelated to bee abundance, possibly due to seed-eating weevils [ABSTRACT FROM AUTHOR]

Plants synthesize a plethora of chemical defence compounds, which vary between evolutionary lineages. We hypothesize that plants evolved the ability to utilize defence compounds synthesized and released by neighbouring heterospecific plants. In two experiments, we incubated clover (Trifolium repens L.) seedlings with individual benzoxazinoid (BX) compounds (2,4-dihydroxy-1,4-benzoxazin-3-one, 2-hydroxy-1,4-benzoxazin-3-one, benzoxazolinone, and 6-methoxy- benzoxazolin-2-one), a group of bioactive compounds produced by cereals, to allow clover BX uptake. Subsequently, we transplanted the seedlings into soil and quantified BX root and shoot content and invasion of root-knot nematodes in clover roots up to 8 weeks after transplantation. We show that clover root uptake of BXs substantially enhanced clover's resistance against the root-knot nematode Meloidogyne incognita. This effect lasted up to 6 weeks after the clover roots were exposed to the BXs. BXs were absorbed by clover roots, and then translocated to the shoots. As a result of clover metabolization, we detected the parent BXs and a range of their transformation products in the roots and shoots. Based on these novel findings, we envisage that co-cultivation of crop species with complementary and transferable chemical defence systems can add to plant protection. [Display omitted] • Clover roots take up and metabolize cereal benzoxazinoids (BXs). • BXs are translocated into aboveground clover tissues. • BX transformation products are a result of enzymatic reactions in clover. • BXs uptake enhanced clover's resistance against root-knot nematodes. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi and rhizobia are soil symbiotic microorganisms involved in plant nitrogen (N) acquisition, whereas it is unclear how single or combined inoculation of both contributes to soil total N in legume crops. This study analyzed the effects of single or combined inoculation with arbuscular mycorrhizal fungus (Paraglomus occultum) and rhizobium (Rhizobium leguminosarum bv. trifolii) on growth performance, root soluble protein, leghemoglobin, NH 4 +-N, NO 3 −-N, and N concentrations, nitrogenase activities, soil total N contents, N contents in glomalin-related soil protein (GRSP), as well as the contribution of N in GRSP to soil total N in white clover. Twelve weeks after inoculation, P. occultum promoted nodule formation, and R. leguminosarum bv. trifolii accelerated root mycorrhizal colonization. Single or combined inoculation with P. occultum and R. leguminosarum bv. trifolii improved biomass, root total length, surface area and volume, root soluble protein concentrations, nodule leghemoglobin concentrations, and nitrogenase activities to varying degrees, with the trend of improvement being more pronounced with combined inoculation. R. leguminosarum bv. trifolii and/or P. occultum significantly increased NO 3 −-N , NH 4 +-N, and total N concentrations in nodules and roots, as well as soil total N concentrations. The N in easily extractable GRSP (EE-GRSP) and difficultly extractable GRSP (DE-GRSP) was 4.37–5.64 mg/g and 6.69–7.83 mg/g, respectively, contributing 2.68–3.26 % and 2.28–3.10 % of soil total N. P. occultum and combined inoculation accelerated the production of EE-GRSP and DE-GRSP and N in EE-GRSP. R. leguminosarum bv. trifolii not only significantly increased DE-GRSP production but also reduced N in DE-GRSP. R. leguminosarum bv. trifolii or P. occultum significantly increased the contribution of N in DE-GRSP, not EE-GRSP, to soil total N. It was concluded that arbuscular mycorrhizal fungus and rhizobium accelerated N accumulation and contribution to soil total N in white clover by DE-GRSP. • AMF promoted nodule formation, and rhizobia accelerated AMF colonization. • AMF and rhizobia improved soil total N and root N levels. • AMF and rhizobia raised root N-fixing capacity. • AMF and rhizobia accelerated GRSP production and N EE-GRSP. • AMF or rhizobia contributed to soil total N via N DE-GRSP , not N EE-GRSP. [ABSTRACT FROM AUTHOR]

Fertiliser applications significantly contribute to agricultural greenhouse gas emissions. While crop yields and quality depend on the type and amount of chemical fertiliser supplied, there are limitations to fertiliser use, as continuous application of inorganic fertilisers can negatively affect soil fertility and result in mineral leaching. Organic fertiliser produced by Anaerobic Digestion (AD) of sewage waste (AD digestate) has been proposed as a substitute for chemical fertilisers. To investigate the potential for the use of AD digestate in pasture systems, grassland field trials were conducted on three independent farm enterprises in Ireland. AD digestate and chemical fertilisers were applied separately or in various combinations and the effects on soil mineral content, grass yield and quality compared. The analyses revealed significant improvement of soil nitrification activity along with improved fodder yield and quality. In particular, digestate application increased crude protein content of fodder by up to 22.8 % compared to fodder from plots without digestate application, that had up to 14.8% crude protein. The increase could be attributed to the white clover percentage increase from 2% (no AD digestate) to up to 31% on plots where AD digestate was applied. Strikingly, grass yields were 1.5-2-fold higher than the five-year national average (of 59.7 ± 4 kg DM/ha/day) on the plots where AD digestate was applied, either alone or in combination with chemical fertilisers. The results of this study highlight the potential of AD digestate application as a more sustainable alternative to inorganic fertilisers in grass-based pasture systems. [Display omitted] • AD digestate application increases grass yield and quality of fodder. • AD digestate improves soil health, in particular soil nitrification activity. • AD digestate application may improve plant biodiversity of grass swards. • AD digestate increases grass yield during extended drought periods. [ABSTRACT FROM AUTHOR]

The legumes white melilot (Melilotus albus ʻMebaʼ) and white clover (Trifolium repens ʻJuraʼ) were tested for their suitability as intercrops for fast growing poplar hybrids grown as short rotation coppice (Populus nigra × P. maximowiczii ʻ Max-4ʼ, P. maximowiczii × P. trichocarpa ʻ NE-42ʼ and P. trichocarpa × P. koreana ʻ P-468ʼ). Legumes were sown in the established poplar plantation after its first harvest (5 years after the establishment of the plantation) and their effect on soil nitrogen, vegetation undergrowth and poplar growth was monitored for two years. All three parameters were influenced by the legume intercrops but the effect depended on the poplar clone, legume species and their interaction. In P-468 white clover lowered inter-year decline of soil nitrogen content, increased the Ellenberg indicator value for nutrients and promoted height increment. Such an effect was not detected in the other two poplar hybrids probably due to insufficient establishment of clover. Plots sown with legumes and subjected to weeding exhibited profound differences of the understorey vegetation compared to controls. The difference persisted even during the second year after legume growth had largely receded. Our results indicate a short-term potential of white clover to contribute to poplar growth, and N supply in poplar plantations. Further studies should explore the benefits of clover intercropping from a long-term perspective, with additional poplar clones and under different climate-soil conditions. • Co-cultivation of white clover (Trifolium repens ʻJura') with hybrid poplar P. trichocarpa × P. koreana ʻP-468′ improved soil nitrogen and poplar growth. • Though transient the presence of white clover had high impact on poplar plantation understorey composition. • N-fixing white clover significantly promoted nitrophilous species as indicated by the Ellenberg indicator value for nutrients. [ABSTRACT FROM AUTHOR]

In sheep production systems, diet type is an important factor affecting the eating quality of the meat produced. The objective of this study was to assess the effect of binary swards on the slaughter performance, descriptive sensory profile, consumer liking and instrumental texture of lamb meat. Five dietary treatments were investigated, perennial ryegrass (Lolium perenne L.; PRG), PRG plus white clover (Trifolium repens L.; PRG+WC), PRG plus red clover (Trifolium pratense L.; PRG+RC), PRG plus chicory (Chicorium intybus L.; PRG+Chic) and PRG plus plantain (Plantago lanceolata L.; PRG+Plan). Post – weaning sixty Texel sired crossbred lambs (n = 12 per dietary treatment) were selected from the main cohort of lambs born in 2022 and further balanced for sex and reared litter size. The M. longissimus thoracis et lumborum (LTL) was obtained from each lamb post-slaughter. Meat samples were analysed by a trained sensory panel, a consumer panel as well as Warner-Bratzler shear force (WBSF) measurements. All data were analysed using a linear mixed model PROC MIXED in SAS. Mean slaughter weights of 46.0 ± 0.36 kg and cold carcass weights of 22.2 ± 0.51 kg were achieved with no differences observed across dietary treatments (P > 0.05). On average, lambs were 217 d of age at slaughter. Lambs finished on PRG and PRG+Plan had similar growth rates, however binary mixtures containing PRG plus any one of WC, RC (P < 0.01) or Chic (P < 0.05) increased average daily gain (ADG) and reduced the number of days required for lambs to reach slaughter (P < 0.05), relative to lambs grazing the PRG monoculture. Meat from PRG+Plan lambs was scored lower by the trained sensory panel for initial tenderness (P < 0.001) and overall tenderness (P < 0.001) when compared to meat from any other dietary treatment. Consumers scored meat from PRG or PRG+WC lambs higher for tenderness (P < 0.05) and flavour (P < 0.01) in comparison to meat produced from PRG+Plan lambs. Relative to meat from PRG+Plan lambs, PRG, PRG+WC and PRG+Chic lamb meat scored higher for overall liking (P < 0.01) when assessed by the consumer panel. Results show that companion forage inclusion increased lamb growth performance in the post-weaning period thus reducing age at slaughter. However, findings suggest that the addition of plantain to the grazed sward may negatively affect the eating quality of lamb meat, highlighting the need to consider diet type in tandem with meat eating quality when selecting finishing systems for pasture fed lambs. • Companion forage inclusion generally increased average daily gain post-weaning and reduced age at slaughter. • Meat from lambs grazing perennial ryegrass and plantain received lower scores for sensory tenderness when assessed by the trained and consumer panels. • Meat quality attributes must be considered when selecting lamb-finishing diets. [ABSTRACT FROM AUTHOR]

This study compared the fertiliser effects of different types of liquid anaerobic digestates on the growth of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), and on soil's primary plant macronutrients and microbial abundance. A factorial design with seven fertilisers and one control (five liquid anaerobic digestates, undigested cattle slurry, calcium ammonium nitrate (CAN) 27% N, and no fertiliser) and four plant schemes (monocultures of perennial ryegrass and white clover, a mix of both, and bare soil) were tested. Plant (forage yield, leaf area index (LAI), canopy height and root mass) and soil (concentrations of total N, Morgan's extracted P and K) responses were measured, as well as soil bacterial/archaeal (16S) and fungal (18S) gene copy numbers (GCN). Digestates and cattle slurry with different chemical compositions, when balanced in terms of the quantity of dry matter applied, had comparable forage yield responses (p > 0.05), with higher yields than CAN mostly observed in ryegrass and mixed vegetation (p < 0.05). The presence of white clover contributed to higher soil N (p < 0.05). Soil available P was increased by biofertiliser applications (p < 0.05). Soil available K was influenced by the interaction between biofertiliser and type of plant (p < 0.05), with ryegrass/mixed swards showing lower K concentrations than white clover and bare soil. Soil bacterial (16S) GCN responded to the interaction between fertiliser/vegetation (p < 0.05), while archaeal (16S) and fungal (18S) GCN only to the type of vegetation (p < 0.05). The application of anaerobic digestates showed low direct impacts on the microbial GCN of the soil, mostly influenced by type of vegetation. The biofertilisers showed comparable performances and effects, despite substantial differences between their chemical compositions, indicating a possible complex matrix of interactions between fertiliser-plant-soil-environment. • Different types of anaerobic digestates drove comparable forage yield responses. • Ryegrass showed better response to anaerobic digestates fertilisation than white clover. • Anaerobic digestate application had low influence on soil microbial numbers. • The type of vegetation had strong influence on soil microbial numbers. [ABSTRACT FROM AUTHOR]

Low-heat skim milk powder (LHSMP) was manufactured on 3 separate occasions in mid lactation (ML, July 4–20) and late lactation (LL, September 27 to October 7) from bulk milk of 3 spring-calving dairy herds on different feeding systems: grazing on perennial ryegrass (Lolium perenne L.) pasture (GRO), grazing on perennial ryegrass and white clover (Trifolium repens L.) pasture (GRC), and housed indoors and offered total mixed ration (TMR). The resultant powders (GRO-SMP, GRC-SMP, and TMR-SMP) were evaluated for composition and color and for the compositional, physicochemical, and processing characteristics of the reconstituted skim milk (RSM) prepared by dispersing the powders to 10% (wt/wt) in water. Feeding system significantly affected the contents of protein and lactose, the elemental composition, and the color of the LHSMP, as well as the rennet gelation properties of the RSM. The GRO and GRC powders had a higher protein content; lower levels of lactose, iodine, and selenium; and a more yellow-green color (lower a* and higher b* color coordinates) than TMR powder. On reconstitution, the GRO-RSM had higher concentrations of protein, casein, and ionic calcium, and lower concentrations of lactose and nonprotein nitrogen (% of total N). It also produced rennet gels with a higher storage modulus (G′) than the corresponding TMR-RSM. These effects were observed over the combined ML and LL period but varied somewhat during the separate ML and LL periods. Otherwise, feeding system had little or no effect on proportions of individual caseins, concentration of serum casein, casein micelle size, casein hydration, heat coagulation time, or ethanol stability of the RSM at pH 6.2 to 7.2, or on the water-holding capacity, viscosity, and flow behavior of stirred yogurt prepared by starter-induced acidification of RSM. The differences in the functionality of the LHSMP may be of greater or lesser importance depending on the application and the conditions applied during the processing of the RSM. [ABSTRACT FROM AUTHOR]

Through clearing and use of fertilizer and legumes, areas of southwestern Australia's unique coastal sand plains can support relatively low-cost dairies. However, the ancient, highly weathered nature of the soils in this region makes the dairies susceptible to a range of threats, including nutrient leaching and erosion. Despite this, Western Australian dairy cows typically produce up to 5,500 L of milk per head annually supported by inorganic nitrogen (N) fertilizer (commonly 50:50 urea and ammonium sulfate) at rates up to <320 kg of N/ha per year. Where hotspots exist (up to 2,000 kg of N/ha per year), total N exceeds pasture requirements. We investigated plant and soil bacteria responses to N fertilizer rates consistent with Australian legislated production practices on dairy farms for pure and mixed swards of white clover (Trifolium repens) and Italian ryegrass (Lolium multiflorum) in a long-term pasture experiment in controlled glasshouse conditions. Although the soil bacterial community structure at phylum level was similar for white clover and Italian ryegrass, relative abundances of specific subgroups of bacteria differed among plant species according to the N fertilizer regimen. Marked increases in relative abundance of some bacterial phyla and subphyla indicated potential inhibition of N cycling, especially for N hotspots in soil. Ammonium concentration in soil was less correlated with dominance of some N-cycling bacterial phyla than was nitrate concentration. Changes in bacterial community structure related to altered nutrient cycling highlight the potential for considering this area of research in policy assessment frameworks related to nutrient loads in dairy soils, especially for N. [ABSTRACT FROM AUTHOR]

The untargeted metabolic profiles of ripened Maasdam cheese samples prepared from milk derived from three herd groups, fed: (1) indoors on total mixed ration (TMR), or outdoors on (2) grass only pasture (GRA) or (3) grass and white clover pasture (CLO) were studied using high resolution nuclear magnetic resonance (1H NMR), high resolution magic angle spinning nuclear magnetic resonance (1H HRMAS NMR) and headspace (HS) gas chromatography mass spectrometry (GC-MS). A total of 31 compounds were identified using 1H NMR and 32 volatile compounds including 7 acids, 5 esters, 4 alcohols, 4 ketones, 4 sulfur compounds, 2 aldehydes, 3 hydrocarbons, 2 terpenes and a lactone were identified using GC–MS in Maasdam cheeses ripened for 97-d. On comparing the 1H NMR metabolic profiles, TMR-derived cheese had higher levels of citrate compared to GRA-derived cheese. The toluene content of cheese was significantly higher in GRA or CLO compared to TMR cheeses and dimethyl sulfide was identified only in CLO-derived cheese samples as detected using HS GC–MS. These compounds are proposed as indicator compounds for Maasdam cheese derived from pasture-fed milk. Clear differences between outdoor or indoor feeding systems in terms of cheese metabolites were detected in the lipid phase, as indicated by principal component analysis (PCA) from 1H HRMAS NMR spectra, although differences based on PCA of all 1H NMR spectra and HS-GC–MS were less clear. Overall, this study presented the metabolite profile and identified specific compounds which may be useful for discriminating between ripened Maasdam cheese and related cheese varieties manufactured from indoor or outdoor herd-feeding systems. Unlabelled Image • Milk of indoor-fed cows led to higher levels of citrate in cheese. • Milk of pasture-based cows led to higher levels of toluene in cheese. • Feeding white clover to cows increased dimethyl sulfide levels in cheese. [ABSTRACT FROM AUTHOR]

Grazed grass is the cheapest feed available for dairy cows in temperate regions; thus, to maximize profits, dairy farmers must optimize the use of this high-quality feed. Previous research has defined the benefits of including white clover (Trifolium repens L.) in grass swards for milk production, usually at reduced nitrogen usage and stocking rate. The aim of this study was to quantify the responses in milk production of dairy cows grazing tetraploid or diploid perennial ryegrass (Lolium perenne L.; PRG) sown with and without white clover but without reducing stocking rate or nitrogen usage. We compared 4 grazing treatments in this study: tetraploid PRG-only swards, diploid PRG-only swards, tetraploid with white clover swards, and diploid with white clover swards. Thirty cows were assigned to each treatment, and swards were rotationally grazed at a farm-level stocking rate of 2.75 cows/ha and a nitrogen fertilizer rate of 250 kg/ha annually. Sward white clover content was 23.6 and 22.6% for tetraploid with white clover swards and diploid with white clover swards, respectively. Milk production did not differ between the 2 ploidies during this 4-yr study, but cows grazing the PRG-white clover treatments had significantly greater milk yields (+596 kg/cow per year) and milk solid yields (+48 kg/cow per year) compared with cows grazing the PRG-only treatments. The PRG-white clover swards also produced 1,205 kg of DM/ha per year more herbage, which was available for conserving and buffer feeding in spring when these swards were less productive than PRG-only swards. Although white clover is generally combined with reduced nitrogen fertilizer use, this study provides evidence that including white clover in either tetraploid or diploid PRG swards, combined with high levels of nitrogen fertilizer, can effectively increase milk production per cow and per hectare. [ABSTRACT FROM AUTHOR]

This research attempted to investigate the plant/soil concentration ratios (CRs) of 137Cs and 40K in plants that grow on the Anzali Lagoon of the Caspian coast, Iran. The activity concentrations of 137Cs and 40K were measured in soil samples, annual plants (Echinochloa crus-galli, Digitaria sanguinalis , and Trifolium repens), and perennial plants (Phragmites australis, and Cynodon dactylon). The relationship of activity concentration with soil particle density, and pH of soil samples, CR, and 137Cs/40K discrimination factor (DF) were determined. The activity concentration of 137Cs in the soil, annual plants, and perennial plants ranged between 12- and 124 (Bq/kg dry weight), 2- and 17 (Bq/kg dw), and 2 - and 14 (Bq/kg dw), respectively. The geometric mean (GM) values of DF in annual and perennial plants were 0.57 and 0.55, respectively. The CR for 137Cs and 40K varied as a non-linear relation in annual plants and perennial plants. This study showed that the CRs for 137Cs in annual plants were higher than the CRs for perennial plants. Unlabelled Image • Calculation of 137Cs and 40K activity concentration in soil and plant species • Evaluation of 137Cs/40K discrimination factor (DF) in plant species • Calculation the concentration ratios (CRs) of 137Cs and 40K in plant species • Comparison of 40K and 137Cs CR in annual plant and perennial plant species [ABSTRACT FROM AUTHOR]

Abstract Trifolium pratense (red clover) and T. repens (white clover) inoculated with Rhizobium leguminosarum sv. trifolii strain U204 are used to improve pastures in Uruguay. Although inoculation is a common practice in the country, there has been a progressive abandonment by farmers because they do not always see the benefits. The presence of efficient rhizobial populations may be one of the reasons why a response to inoculation is not always observed. We studied the identities and phylogenetic relationships among the clover rhizobia populating Uruguayan soils by analysis of 16S rRNA genes, ITS sequences and housekeeping (atpD , glnII , recA , rpoB) and symbiotic (nodA , nodC , nifH) genes. Strains like P3 and P33, isolated from the endemic Trifolium polymorphum , are inefficient in red and white clover. These strains clustered separately from the symbionts of these clovers. Bacteria which are efficient in red and white clovers clustered in either of two groups: one, represented by isolate 249, are likely naturalized rhizobia derived from the inoculant U204; and other included strains like U317 and N2, which share symbiotic genes with the inoculant. We hypothesize that these strains may be derived from native strains that acquired symbiotic gene from inoculant strains. These types of rhizobia are strong candidates for a second generation of clover inoculants for Uruguay. Highlights • Clover rhizobia in Uruguayan soils are genetically and functionally diverse. • Introduced clover inoculant strains give rise to new rhizobia in Uruguayan soils • Inoculant adaptation to environmental conditions produces naturalized clover rhizobia. • Acquisition of symbiotic genes by native bacteria also generates new clover rhizobia. • New rhizobia are a source for second-generation clover inoculants in Uruguay. [ABSTRACT FROM AUTHOR]

• Urine volume and N concentration influences relative N loading onto the soil. • Forages with low DM% present an opportunity to modulate cows' urination behavior. • Feeding chicory or plantain had a positive effect on milk production in dairy cows. • Cows fed the herbs urinated more often and greater volumes per day than ryegrass. • Urinary N concentration was lower from cows grazing the herbs than ryegrass. Urine patches from ruminant livestock are risk areas for soil nitrogen (N) loss from grazed pastures. Urine volume and N concentration at any given urine event influences the relative N loading onto the soil. Forages such as chicory (Cichorus intybus L.) and plantain (Plantago lanceolata L.) with high water and mineral content present an opportunity to modulate urination behaviour and urinary nitrogen (UN) excreted into the environment. This study compares urination patterns, milk production and N use efficiency, of cows grazing chicory, plantain, or ryegrass (Lolium perenne L.) with 13% white clover (Trifolium repens L.; RGWC) herbage. Fifty-four Friesian x Jersey cows in late lactation were blocked into replicated groups of six cows, and offered one of three pasture types. Automated urine sensors measuring urine volume and timing were affixed to approximately 10 random cows per treatment for 24 h. Milk yield was similar for all treatments (19.1 ± 0.52 kg/cow.day), but milk solids production (protein + fat) were greater from cows grazing chicory than RGWC (1.86 vs 1.72 kg MS/cow.day, P < 0.01) while plantain was intermediate (1.76 kg MS/cow.day). There was large variation in urine event volume (0.13–11.6 l per event), though mean urine volume per event was similar for each treatment (3.01 ± 0.3 l per event; P = 0.24). Water, sodium and potassium intakes from herbage was greatest for chicory compared with plantain or RGWC. Frequency of urination increased with increasing water, sodium and potassium intakes and cows grazing chicory and plantain urinated more often (28.6 and 21.2 events/cow.day, respectively) than those grazing RGWC (13.9 events/cow.day, P < 0.05). Consequently, cows grazing chicory excreted 1.5 and 2.4 times more urine per day (P < 0.01) than cows grazing plantain and RGWC, respectively. Apparent N intake was similar between cows grazing chicory and RGWC, but greater than cows grazing plantain. However, UN concentrations from cows grazing chicory and plantain were similar (P > 0.05), but substantially lower than RGWC (1.3 vs 4.8 g/kg; P < 001). The reduction in UN in cows grazing herbs is mainly attributed to increased number of urinations, which resulted in urine dilution. The combination of similar urine volume per event in all three forages, frequent urinations and substantially lower UN concentration in cows grazing the forage herbs indicate a benefit from forage herbs to reduce N load onto pasture. [ABSTRACT FROM AUTHOR]

Grasslands with dense fibrous roots and higher biological soil crust coverage generally show great performance of sediment reduction and runoff maintenance during the two-year experiments. Gramineae grasslands are effective in maintaining runoff and reducing sediment, which can be considered as a suitable management practice to achieve the sustainability of the socio-ecological systems during vegetation restoration in semi-arid areas. Large-scale vegetation restoration generally reduces local water yield and influences river ecosystem health. Thus, scientific evaluation of vegetation restoration consequences is necessary for maintaining the stability of the surface water system and water cycle in semi-arid regions. In this study, we compared the efficiencies of different typical grasslands in regulating runoff and sediment yields and proposed feasible suggestions suiting for local environments. Four grasslands, including two Gramineae species (Elymus dahuricus and Bromus inermis) and two legume species (Medicago sativa and Trifolium repens), were tested during a two-year period with simulated rainfall experiments, and using bare land as control. Three replicates were done for each treatment, and fifteen plots with a slope of 20° were constructed. Three indices were used to assess the runoff and sediment yields reduction capacity of the grasslands, including runoff reduction benefit (RRB), sediment reduction benefit (SRB), and soil infiltration rate (SIR). The results showed that RRB and SRB were significantly different (P < 0.05) among treatments across the two-year experiments. The values of SRB increased considerably in the second year. In particular, the values of SRB for E. dahuricus and B. inermis was 98.79% and 98.07%, respectively, while that of RRB was −11.84% and 4.01%, respectively. The two Gramineae grasslands showed greater effectiveness in sediment reduction and runoff maintenance than the two legume species owing to the dense fibrous roots and higher biological soil crust coverage. Therefore, Gramineae grasslands can be considered as a suitable management practice to achieve the socio-ecological sustainability of the semi-arid areas during vegetation restoration. [ABSTRACT FROM AUTHOR]

Highlights • The spermidine (Spd) could induce H 2 S signaling through activating L/DCD pathway in white clover. • The H 2 S signaling is involved in the Spd-regulated bZIP37, bZIP107, DREB2, DREB4, WRKY108715 , and antioxidant defense under dehydration. • H 2 S acts as a downstream signaling of hydrogen peroxide (H 2 O 2) and nitric oxide (NO) in response to dehydration. • The crosstalk among Ca2+, H 2 O 2 , NO, and H 2 S involves Spd-regulated antioxidant and transcription factors associated with dehydration tolerance. Abstract Hydrogen sulfide (H 2 S) nowadays is regarded as a novel gaseous signaling molecule in plants during environmental stress response. The spermidine (Spd), an important plant growth regulator, plays critical roles in regulating stress tolerance in plant species. Objectives of this study were to examine whether Spd could act as a H 2 S signaling activator to regulate stress-responsive transcription factors (TFs) and antioxidant defense and to further explore the possible crosstalk among Spd-induced hydrogen peroxide (H 2 O 2), nitric oxide (NO), and H 2 S signaling in leaves of white clover. Results showed that dehydration or exogenous application of Spd could significantly increase L/D-cysteine desulfhydrate (L/DCD) activities and then cause a quick accumulation of H 2 S, followed by significant improvement of antioxidant enzyme (SOD, CAT, GPOX, APX, GR, DHAR, and MDHAR) activities and transcript levels of TFs (bZIP37 , bZIP107 , DREB2 , DREB4 , and WRKY108715) and genes encoding antioxidant enzymes. The inhibitors (AOA and NH 2 OH) of L/DCD activities could effectively attenuate dehydration- or Spd-induced these effects in leaves. Additionally, dehydration-induced increase in H 2 S accumulation, L/DCD and antioxidant enzyme activities, and genes expression were remarkably abolished by the application of Spd biosynthesis inhibitor (DCHA), whereas exogenous Spd significantly alleviate the inhibitory effect of DCHA on these parameters under dehydration condition. This indicated that H 2 S which was derived from L/DCD pathway might act as a downstream signaling of Spd, and Spd-activated H 2 S signaling was involved in dehydration-regulated TFs and antioxidant defense associated with dehydration tolerance. Further analyses found that Spd-induced H 2 O 2 production could not be attenuated by scavengers of NO and H 2 S, but the scavenger of H 2 O 2 effectively inhibited Spd-induced increases in NO and H 2 S. The Spd-induced H 2 S signaling was also substantially inhibited by the application of the NO scavenger. The result implied that Spd-induced H 2 O 2 could be an upstream signal molecule of NO and H 2 S, and the Spd-induced H 2 S might act as the downstream signaling of NO in leaves. These obtained results provide the basic evidence to understand Spd-regulated signal transduction in white clover. [ABSTRACT FROM AUTHOR]

Abstract Protein hotspots in soil, such as those associated with decaying soil fauna or plant litter, may produce ephemeral patches of disproportionately high soil nutrients. These hotspots may occur at the macro- and microscale in close proximity to plant roots, however, the likely concentration of soluble products produced in these hotspots remains poorly understood. To address this, we buried two contrasting biomass residues in soil, namely earthworm (Lumbricus terrestris) and clover (Trifolium repens). Their transformation to amino acids, NH 4 + and NO 3 − were monitored continually over 6 days using microdialysis. All treatments showed greater soluble nitrogen (N) concentrations compared to the unamended controls. The highest concentrations of both amino acids (12.9 mM after 12 h) and NH 4 + (45.3 mM after 6 h) were generated in the vicinity of decomposing earthworm. In comparison, dried clover residues yielded 2.7 mM of amino acids at 6 h. After 12 h, amino acid and NH 4 + concentrations in both earthworm and dried clover treatments showed a steep decline, returning close to background levels (<20 μM). Through the use of microdialysis we are able to show that soil nutrient hotspots may provide nearby roots with concentrations of amino acids and NH 4 + several orders of magnitude higher than found in the bulk soil solution. Highlights • Protein-rich hotspots provide significantly higher N concentrations compared to bulk soil. • Ephemeral nutrient hotspots may provide significant quantities of amino acids to nearby roots. • Microdialysis provides a high spatial and temporal resolution for SOM sampling. [ABSTRACT FROM AUTHOR]

• The vetch aphid, Megoura viciae could indeed sequester l -DOPA from Vicia faba in its body. • M. viciae may sequester l -DOPA to help in its melanization process for ecological adaptation. • Internal l -DOPA synthetase of M. viciae is still functional, especially when extra l -DOPA is removed from the diet. Melanism in insects is important for their physical protection, immunoreactions, and sclerotization. The vetch aphid, Megoura viciae (Buckton), has relatively strong tanning in its prothorax, head, antennae, cornicles, and legs. It was hypothesized that M. viciae may sequester the high level of l -DOPA in its host Vicia faba to help in its melanization process for ecological adaptation. To confirm this hypothesis, the amount of l -DOPA in M. viciae was modified and quantified. We first generated a Trifolium repens (clover, low l -DOPA containing) host to cut off the extra l -DOPA intake by M. viciae. The rate-limiting tyrosine hydroxylase gene of M. viciae (MV-TH) was then cloned and analyzed. To further reduce the l -DOPA level in the insect, RNAi was used to downregulate the transcriptional level of MV-TH. Our results confirmed that M. viciae could indeed sequester l -DOPA in its body, and its ample storage of this amino acid could be the reason for the strong tanning of its body. M. viciae reared on T. repens could upregulate its MV-TH to enhance l -DOPA biosynthesis and thus maintain a high level of l -DOPA. The MV-TH repression by RNAi lasted for about 3 days, successfully decreasing the l -DOPA level. Aside from a slight decrease in exuvia tanning, no other obvious change in body appearance was detected in the RNAi-treated insect. Although M. viciae can obtain most of its l -DOPA directly from its original host, its internal l -DOPA synthetase is still functional, especially when extra l -DOPA is removed from the diet. This capability to enhance its shield ensures the ecological adaptation of this insect. [ABSTRACT FROM AUTHOR]