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We evaluated Italian ryegrass (Lolium multiflorum Lam.) establishment in a factorial of grazing intensity (intense, moderate, moderate‐light, light, and no grazing, with target average sward heights of 10, 20, 30, and 40 cm in the grazed plots) and additional seeding (self‐seeding with or without additional seeding) in an integrated soybean‐beef cattle system in southern Brazil. Grazing treatments were imposed in winter (June–July) and followed by a direct‐seeded soybean crop (November). The establishment was quantified prior to the stocking periods in 2017 and 2018, corresponding to self‐seeding from 2016 and 2017. Intense grazing impaired ryegrass re‐establishment, resulting in larger individual plants (0.54 vs. 0.15 g dry matter plant−1) but lower population density (57 vs. 1,355 plants m−2) than in the other treatments. Additional broadcast ryegrass seeding did not fully compensate for the reduced natural reseeding in this treatment. The addition of seeds under intense grazing increased plant population density to values comparable to moderate grazing intensities but reduced individual plant mass, limiting herbage mass attained by the end of the pasture establishment phase. Contrastingly, the various combinations of individual plant mass and population density were sufficient to maintain herbage masses in moderate to light grazing intensities that were comparable to that in the ungrazed treatment, regardless of seed addition (63 vs. 180 g DM m−2 for intense grazing vs. the average of other treatments over the whole establishment phase). Moderate grazing, e.g., target sward heights of 20 cm or greater, is necessary to achieve a system that can sustain itself without seed addition. [ABSTRACT FROM AUTHOR]

Ryegrass (Lolium multiflorum Lam.) is one of the most difficult annual weeds to control in cultivation systems worldwide, especially in temperate regions. The widespread use of herbicides in the past two decades has selected resistant biotypes of ryegrass in crops in Southern Brazil. Ryegrass seeds are dormant when disseminated and germination can be staggered over time (crop‐growing season). Knowledge of the germination behavior of seeds from herbicide‐resistant plants has been little studied, but it would be very useful in integrated weed management. Thus, this study aimed to characterize the dynamics of the soil seed bank of two biotypes of L. multiflorum, one glyphosate‐resistant and the other glyphosate‐susceptible, under a no‐tillage system. The treatments were arranged in a bifactorial scheme, using seeds from biotypes (glyphosate‐resistant and glyphosate‐susceptible) with monthly periods of removal from field (one to 12 months). Seeds of each biotype were placed on the soil surface and covered with soil and straw to simulate no‐till conditions. The percentage of germinated, dormant, and dead seeds was evaluated every 30 days. The ryegrass seed bank of glyphosate‐susceptible and glyphosate‐resistant biotypes was reduced to 11 and 15% of dormant seeds, respectively, at the end of 12 months. However, there was no variation in germination, dormancy, and seed mortality between susceptible and glyphosate‐resistant ryegrass. Seeds of glyphosate‐resistant biotype and susceptible showed germination behavior with similar dynamics in the soil over a period of 12 months. [ABSTRACT FROM AUTHOR]

No‐tillage farming combined with temporary cattle grazing is becoming a common practice in parts of South America. We quantified the effects of no‐tillage and winter grazing of annual ryegrass (Lolium multiflorum Lam.) on soil carbon and nitrogen stock, stratification ratio (concentration in 0–5 to 10–20‐cm layer) and lability (based on particulate organic matter, POM), relative to conventional tillage or ungrazed ryegrass. A 9‐year‐old experiment was conducted in a southern Brazilian Ferralsol. Soil under no‐tillage accumulated 1.11 Mg C ha−1 year−1 and 0.10 Mg N ha−1 year−1 to 100‐cm depth relative to conventional tillage when ryegrass was not grazed, and also increased the stratification ratio of carbon (1.48 vs. 1.11) and nitrogen (1.66 vs. 1.17). The carbon and nitrogen lability was also greater in no‐tillage soil, as carbon and nitrogen stocks increased proportionally more in sand‐POM than in silt or clay size fractions (carbon lability index = 1.57 vs. 1.00; nitrogen lability index = 1.57 vs. 1.00). Semiquinone concentrations in physical fractions were 4–28% smaller in no‐tillage, suggesting less organic matter aromaticity in this treatment. Grazing, however, caused no further improvement of stocks of carbon and nitrogen in the 0–100‐cm layer of no‐tillage soil (e.g., 209 vs. 212 Mg C ha−1, ns), or enhancement of stratification or lability of those elements, relative to ungrazed ryegrass. Overall, no‐tillage effectively promoted soil carbon and nitrogen accumulation and lability in this subtropical Ferralsol, whereas grazing did not compromise the gains of no‐tillage. Highlights: Capacity of no‐tillage and grazing to enhance stocks, stratification and lability of soil C and N.C sequestration with no‐tillage is being debated, and little is known when combined with grazing.No‐tillage accumulated 1.11 Mg C ha−1 year−1 but grazing promoted no further C accumulation.No‐tillage effectively accumulated C in soil and grazing did not compromise such gain of no‐tillage. [ABSTRACT FROM AUTHOR]

The barley culture has been conquering space in Southern Brazil, being an option for rotation with wheat. One of the main constraints for the increased productivity is the race against weed, especially ryegrass. Therefore, this study aimed to evaluate the barley competitive ability (Hordeum vulgare) against the ryegrass (Lolium multiflorum), in relation to the nitrogen absorption and to measure the density in which the culture is negatively affected. For this, a field experiment was conducted using experimental designs of randomized blocks, where the barley coexisted with different ryegrass densities (0, 4, 16, 32, 64 and 128 m-2). The analyzed varieties were plant height, chlorophyll, number of barley and ryegrass stems, barley and ryegrass dry mass, leaf area, number of spikes, number of grains per spike, the weight of a thousand grains and yield. The ryegrass interferes negatively on the barley's development and productivity, even in low densities, being necessary its control to four plants m-2. [ABSTRACT FROM AUTHOR]

The fertilization in rangelands has a positive effect in the forage production. The increased nitrogen (N) availability improves plant growth and forage quality of native pastures. However, in the Pampa biome conditions of Rio Grande do Sul State, Brazil, these responses occur surprisingly fast and consistently. Therefore, the objective of this work was to quantify the N effect in the botanical composition of a natural pasture overseeded with annual ryegrass in Southern Brazil. The effects of three rates of N fertilization (zero, 100 and 200 kg N ha-1) were evaluated. Forage biomass was estimated on a monthly basis using the double sampling approach. The different botanical components of each forage sample were manually sorted in the laboratory. In order to calculate the Rényi diversity profile, two floristic composition evaluations were performed in the experimental area in December of 2010 and September of 2011. The ryegrass biomass production is highly affected by the N fertilization. The botanical composition of natural pastures modifies most probably by increasing ryegrass competition at early spring. [ABSTRACT FROM AUTHOR]

This study tested the hypothesis that different sward structures, which were constructed by varying the pre- and post-grazing sward heights of annual ryegrass pasture ( Lolium multiflorum Lam.) in southern Brazil, affect the short-term intake rate ( STIR) by dairy cows. Treatments consisted of four sward-management strategies defined by a combination of two pre- (25 and 15 cm) and two post-grazing sward heights (10 and 5 cm): 15-05, 15-10, 25-05 and 25-10. A completely randomized block design with four replicates was used for the experimental design. The STIR was determined by the double-weighing technique. Jaw movements were evaluated using automatic recorders ( IGER Behaviour Recorder). The results showed that treatment 25-10 allowed the animals to collect more herbage with a greater bite mass and thus resulted in a greater STIR. Treatments in which sward height was reduced to 10 cm generally favoured the ingestion process than treatments with a post-grazing sward height of 5 cm. [ABSTRACT FROM AUTHOR]

The interest was the seed longevity dynamics of annual ryegrass in natural conditions as an important tool to explain its dynamics in no tillage systems used in the South of Brazil. The species is commonly managed for natural re-sowing and, in this way, allows cattle grazing with reduced costs during the winter time. In February of 2003, twenty bags of nylon screen containing sterilised soil with 100 seeds in each were randomly buried in the field, 5 cm deep. Around every three or four months, four sacks were exhumed. Seeds were counted and tested using germination and tetrazolium tests. The seeds showed high primary dormancy, which was overcome very fast. After 108, 226, 326, 565 and 732 days of burial there were no significant differences as the secondary dormancy of the seeds that did not germinate in autumn was not high. The last exhumation period was significantly different from the others due to the strong decay on seed viability. As few seeds remained viable after 732 days, the soil seed bank was classified as transient, being evident that in annual pastures the transitory seed banks have a main role in the regeneration of the species. [ABSTRACT FROM AUTHOR]

• Trichoderma stimulates resistance against to Pyricularia oryzae in Lolium multiflorum. • Coated seeds of L. multiflorum with T. atroviride reduces the severity of P. oryzae. • Silicon is accumulated in the leaves and improves the resistance to blast. • Biochemical and physical defenses are related to the protective action against blast. Ryegrass (Lolium multiflorum L.) is a forage species with a high content of protein and good palatability and digestibility. In winter, it is frequently used in southern Brazil as feed for livestock. The high humidity in this region is propitious for gray leaf spot, a disease caused by Pyricularia oryzae , considered to be the region's main biotic problem. In this study, we aimed to evaluate the effect of three types of management, namely seed coating with Trichoderma atroviride (T), application of silicon in the soil (Si), and combination of both treatments (TSi), to reduce the severity of gray leaf spot. In the first phase, the capacity of 10 native isolates of Trichoderma spp. were evaluated in vitro for direct inhibition of P. oryzae based on tests of dual cultures (DC), antibiosis for volatile (Vol), and non-volatile compounds (Nvol). In vivo trials involved the ability to induce resistance responses, such as quantifying severity (SEV) and number of lesions (NL) per cm2 of leaf area. In the second phase, the efficacy of T, Si, and TSi was tested under greenhouse conditions. The lesion expansion rate (LER), relative efficiency of infection (RIE), SEV and NL were measured (after inoculation with P. oryzae), and in parallel the activities of the enzymes superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and phenylalanine ammonia-lyase (PAL) were quantified (at 24, 48, 72, and 96 h). The strain TR10 (identified by polyphasic taxonomy as T. atroviride) showed one of the highest inhibition values in Vol (23%) and DC (35%). Plants from seeds treated with the strain TR10 had the lowest levels of SEV (5.5%) and NL (3), in contrast with the other strains according to analysis of variance. Under greenhouse conditions, significant differences (P < 0.0001) were found for LER, RIE, NL and SEV in T, Si, and TSi concerning TE (control treatment). The defense response of T was related to the activities of CAT, POX, and PAL (mainly), while for Si, other mechanisms, which were not evaluated in this study, might have contributed to disease reduction, and TSi did not show an additive effect. The treatment of seeds with T. atroviride and the application of Si in the soil improved the resistance of L. multiforum against infection by P. oryzae. [ABSTRACT FROM AUTHOR]

Ryegrass (Lolium multiflorum Lam.) is the main winter weed of crops in Southern Brazil. High competitiveness, adaptability, widespread resistance to herbicides and seed dormancy make the plant a permanent problem. Herbicides, as well as plant growth regulators, can be used as a management option for ryegrass seed production, however there is no consensus among authors at which stage of the plant the application is most effective. Thus, this study aimed to evaluate the production and physiological quality of ryegrass seeds in response to the application of herbicides and plant growth regulators in three stages of plant development (inflorescence emergence, flowering and fruit development). Each treatment consisted of applying two different doses of each of the active ingredients: ammonium glufosinate, clethodim, glyphosate, iodosulfuron-methyl, paraquat and 2,4-D (herbicides); ethephon and trinexapac-ethyl (plant growth regulators), still an untreated control, totaling 17 treatments for each stage of development. The experimental design used was randomized blocks, with three replications. The variables evaluated were: seed production (kg ha−1), thousand seed weight (g), viability (%), germination (%), first germination count (%), dormant seeds (%) and dead seeds (%). The ryegrass seed production reduced 100% with clethodim, glyphosate, ammonium glufosinate or paraquat applied in the inflorescence emergence or flowering stages. In the fruit development stage, all treatments (herbicides and plant growth regulators) caused deleterious effects on seed production, the greatest effect occurred with paraquat (95%). Paraquat, ammonium glufosinate and clethodim affected the physiological quality of the seeds when applied in fruit development stage. This research demonstrated that the application of herbicides in the ryegrass reproductive stage decreases its seedbank replenishment (natural re-sowing), with the potential to harm its progeny. [ABSTRACT FROM AUTHOR]