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A specialized hoe opener was engineered for no-till systems to apply substantial amounts of wheat seeds and granular fertilizers, effectively suppressing early stage weeds. This distinctive hoe opener plants wheat seeds within a 120 mm wide horizontal band, positioning granular fertilizers precisely at the band's center, all accomplished in a single pass. Notably, the design excels at covering the fertilizer with soil aggregates, compacting it through a wheat separator, and concurrently depositing wheat seeds from above. Our primary research objectives centered on achieving a consistent seedbed post-fertilizer application and ensuring a uniform distribution of wheat seeds within the horizontal band. The DEM (Discrete Element Method) was exploited to optimize the hoe opener's parameters. Through extensive simulations and comparisons with experimental outcomes, an optimal wing orifice AB length of 60 mm was identified, effectively covering granular fertilizers with soil aggregates and achieving compaction through the wheat separator. Furthermore, parameters of the wheat seed separator's hump were fine-tuned using the Box–Behnken algorithm, resulting in an optimal dimension of 40 mm for the top radius (A), 140 degrees for the top angle (B), and 90 mm for the bottom length (C). [ABSTRACT FROM AUTHOR]

Field experiments was conducted at the Teaching and Research Farm, Joseph Sarwuan Tarka University Makurdi to evaluate the effect of bed types and fertilizer types on the growth and yield of onion seedlings/bulbs (Allium cepa L.). The study was a 2x4 factorial experiment {2 types (bed and ridge) and four fertilizer types (NPK20:10:10, poultry manure, cattle dung, and no application served as control)} laid out in a Randomized Complete Block Design (RCBD) replicated thrice. Data were collected were subjected to Analysis of Variance (ANOVA) and Fisher's least significant difference (FLSD) was used to separate means. Results of the study revealed that onions raised on beds had statistically higher growth and yield parameters than the ridge bed system. Therefore, the onion planted on bed type system recorded the highest yields with bulb weight (13.45t/ha) and (23.35 t/ha) in both years. On the fertilizer types, NPK 20:10:10 application recorded the highest bulb weight of 14.57t/ha and 35.75t/ha in both years, followed by poultry manure with bulb weight of 11.29t/ha and 11.61t/ha and cattle dung with bulb weight of 10.70t/ha and 12.94t/ha while untreated (control) gave the lowest yields with bulb weight/plot 9.21t/ha and 7.40t/ha respectively. It is recommended that the application of NPK 20:10:10 fertilizers on bed type system be adopted for optimum yield of Onions in Makurdi, Nigeria. Furthermore, in the scarcity or high cost of NPK fertilizers, smallholder farmers in the study location can adopt either poultry manure or cattle dung as a substitute to boost yields of onions. [ABSTRACT FROM AUTHOR]

Soil temperature is the main factor in determining the germination of maize seeds and the emergence time of the crop. It controls the rate of phenological development while the meristem is underground, which is until the V6 (six leaf collar) stage of maize. The research performed by the authors aimed to model maize seedbed temperatures at sowing depth (soil temperature at 5 cm depth) during the sowing-emergence-early development period. The research is based on measurements in ploughed plots of the maize experiments at the Látókép Experiment Site of the University of Debrecen (Eastern Hungary) in two growing seasons of 2021–2022. Two types of empirical models were established, a multilinear regression model (M1) and a dynamic-empirical model (M2), where the daily increase and decrease of soil temperature are determined by multilinear regression. Candidates for input variables for both models were various, easily available daily meteorological parameters. M2 model performed better than M1 when applied to an independent database of 2022. This is particularly valid for the maximum and minimum soil temperatures. It was found that both M1 and M2 can be used to predict the soil temperature of the maize seedbed before shading by the plants. For daily mean temperature, M1 and M2 give a similarly good estimation, while the dynamic-empirical model has to be preferred for the maximum and minimum temperatures. M2, which is based on daily temperature, global radiation and wind speed data, predicts the daily mean (RMSE = 1.4°C), maximum (RMSE = 2.2°C), and minimum (RMSE = 1.6°C) of seedbed temperature not worse than many earlier soil temperature models do, even hybrid or mechanistic ones with a large number of parameters. [ABSTRACT FROM AUTHOR]

Large clods (centimetres in size) can be formed by tillage in clayey paddy fields where upland crops are planted. These clods cause early water depletion near the soil surface, which decreases crop germination and emergence rates. Because of the difficulty in reducing clod size, desiccation damage to seeds can be avoided by adjusting the seeding depth based on the clod size‐dependent soil moisture profile. This study aimed to clarify the effect of clod size on (1) the evaporation rate (E) and soil moisture profile and (2) the mobility of soil water during the drying process. Evaporation experiments were conducted in an air‐conditioned greenhouse with natural light using cylindrical columns filled with artificially made clods 3 (L columns) and 1 cm (S columns) in diameter. We measured E, potential evaporation rate (PE), and total soil moisture content (wtot) throughout the experiment and the soil moisture profiles at the end of the experiment. The water diffusivity (Dw) and apparent vapour diffusion coefficient (dvap) were calculated as the mobility of soil water and water vapour, respectively. We found that wtot was lower in the L column than in the S column, although not at the onset of the experiment. At the end of the experiment, the soil moisture content was lower in the L column than in the S column throughout the soil layer. In contrast, E/PE was higher in the L column than in the S column throughout the experiment and even at the same wtot. Regarding mobility, Dw was slightly greater in the L column than in the S column in the soil moisture content range, where vapour movement could be greater than liquid water movement. In addition, the ratio of dvap to the diffusion coefficient of water vapour in soil was higher than unity in both columns and was 2.4–3.2 times higher in the L column than in the S column. In summary, larger clods caused a higher evaporation rate and lower soil moisture content, owing to the increased enhancement of water vapour movement probably induced by wind. [ABSTRACT FROM AUTHOR]

Liming before cultivation of sugar beets is favourable even on alkaline soils but knowledge of response in other crops is lacking. Therefore, effects of ground limestone (GL) and structure lime (SL1 slaked lime or SL2 mix of ground limestone and slaked lime) were evaluated in southern Sweden on soil structure, growth and nutrient concentration in barley under four fertilisation strategies 1.5–2 years after application. All lime products increased aggregate stability, but with variations between locations. A lower proportion of large aggregates was found in both limed treatments, and a higher proportion of small aggregates in SL. In barley, grain yield was unaffected while shoot numbers and biomass in first node stage increased for GL and biomass increased further for SL. Structure lime increased potassium concentration in plants in first node stage, due to more potassium in the product. Both lime types increased molybdenum concentration. Ground limestone reduced zinc concentration compared with no liming. Finer seedbed tilth and increased aggregate stability may explain increased biomass for GL. Higher potassium content in SL might be a further explanation. No interactions between liming and fertilisation were found. In conclusion, on the soil types studied, no change of fertilisation strategy is needed due to liming.

The application method of granular fertilizers and wheat seeds depends on the colter design and parameters. In this research, a new double disc colter is studied to apply the wheat seeds to the horizontal band 12 cm in width and apply granular fertilizers deeper 2 cm than the wheat seed level precisely to the middle of the band. Applying granular fertilizers and wheat seeds at different levels increases the granular fertilizer dose without harm to the wheat seeds. Furthermore, applying high doses of wheat seeds to the horizontal band decreases the competition between the seeds and suppresses the weeds. Therefore, preparing a plain seedbed after applying the fertilizers and distributing wheat seeds to the horizontal band was the research objective. The comparison experiments of the base and designed double disc colters were provided in the soil bin determining the horizontal and vertical forces and the placement of the fertilizers and seeds. The discrete element method (DEM) was used to track the soil particle behavior interacting with the double-disc colter. The simulation results and actual experiment results were satisfactory when the AB length of the wing orifice was 60 mm. [ABSTRACT FROM AUTHOR]

Resilience of plant communities to disturbance is supported by multiple mechanisms, including ecological legacies affecting propagule availability, species' environmental tolerances, and biotic interactions. Understanding the relative importance of these mechanisms for plant community resilience supports predictions of where and how resilience will be altered with disturbance. We tested mechanisms underlying resilience of forests dominated by black spruce (Picea mariana) to fire disturbance across a heterogeneous forest landscape in the Northwest Territories, Canada. We combined surveys of naturally regenerating seedlings at 219 burned plots with experimental manipulations of ecological legacies via seed addition of four tree species and vertebrate exclosures to limit granivory and herbivory at 30 plots varying in moisture and fire severity. Black spruce recovery was greatest where it dominated pre-fire, at wet sites with deep residual soil organic layers, and fire conditions of low soil or canopy combustion and longer return intervals. Experimental addition of seed indicated all species were seed-limited, emphasizing the importance of propagule legacies. Black spruce and birch (Betula papyrifera) recruitment were enhanced with vertebrate exclusion. Our combination of observational and experimental studies demonstrates black spruce is vulnerable to effects of increased fire activity that erode ecological legacies. Moreover, black spruce relies on wet areas with deep soil organic layers where other species are less competitive. However, other species can colonize these areas if enough seed is available or soil moisture is altered by climate change. Testing mechanisms underlying species' resilience to disturbance aids predictions of where vegetation will transform with effects of climate change. [ABSTRACT FROM AUTHOR]

The low productivity of cocoa plantations in Indonesia is partly due to the low quality of seeds, which refers to the impeded growth of cultivated cocoa nurseries. Seed is the initial growth of plants so the importance of giving special treatment to seeds will refer to better seed growth. Provision of Plant Growth Promoting Rhizobacteria (PGPR) microbes can produce indoleacetic acid (IAA) in plants to improve the quality of plant growth. This study aims to determine the effectiveness of the provision of Plant Growth Promoting Rhizobacteria bamboo rhizosphere against cocoa seed germination. The study was carried out in the farmer group garden, Gantarangkeke District, Bantaeng. This study was arranged in the form of a two-factor factorial design (F2F) in a randomized block design (RBD). The use of cocoa seed type as the first factor consisted of GTB (Gantarangkeke Bantaeng) local cocoa seed and MCC 01 cocoa seed and seed immersion treatment at PGPR rhizosphere bamboo concentration as the second factor consisting of 0% (control) concentration, 5%, 10 % and 15%. The results obtained indicate that administration of seeds with bamboo rhizosphere PGPR affects the germination (100.00%), the speed of seed growth (7.14%/etmal), as well as on abnormal seeds (10.00%). So that the provision of bamboo rhizosphere PGPR on cocoa seeds has an effective influence on seed germination and cocoa seedling development.

The application method of granular fertilizers and wheat seeds depends on the colter design and parameters. In this research, a new double disc colter is studied to apply the wheat seeds to the horizontal band 12 cm in width and apply granular fertilizers deeper 2 cm than the wheat seed level precisely to the middle of the band. Applying granular fertilizers and wheat seeds at different levels increases the granular fertilizer dose without harm to the wheat seeds. Furthermore, applying high doses of wheat seeds to the horizontal band decreases the competition between the seeds and suppresses the weeds. Therefore, preparing a plain seedbed after applying the fertilizers and distributing wheat seeds to the horizontal band was the research objective. The comparison experiments of the base and designed double disc colters were provided in the soil bin determining the horizontal and vertical forces and the placement of the fertilizers and seeds. The discrete element method (DEM) was used to track the soil particle behavior interacting with the double-disc colter. The simulation results and actual experiment results were satisfactory when the AB length of the wing orifice was 60 mm.

Mechanized transplantation of rice is being imposed worldwide and it requires certain conditions to develop the process efficiently like the production of seedlings in trays. In Cuba, transplanting machines with the system to the filling of the trays are being acquired, so it is necessary to establish a technology that allows the transplanting machines to be put into operation. The objective of this research was to evaluate the quality of rice seedlings to be used in mechanized transplantation under sowing conditions, in Pinar del Río Province, Cuba, with the use of the ERP-60 transplanter. Among the main results obtained in the tray seedbed technology at the time of transplantation, an interaction was found between the factors under study. When the component elements of the substrate were mixed and left at rest, the plants found the appropriate conditions for growth, in the fourelement substrate (ST + MOT + FCSM + CAC), with 30 or more days of rest. This made possible to achieve seedlings of 15.37 cm high and 2.19 mm thick, 19 days after the seed germinated, complying with the requirements for transplantation with the ERP-60 machine. [ABSTRACT FROM AUTHOR]

Liming before cultivation of sugar beets is favourable even on alkaline soils but knowledge of response in other crops is lacking. Therefore, effects of ground limestone (GL) and structure lime (SL1 slaked lime or SL2 mix of ground limestone and slaked lime) were evaluated in southern Sweden on soil structure, growth and nutrient concentration in barley under four fertilisation strategies 1.5–2 years after application. All lime products increased aggregate stability, but with variations between locations. A lower proportion of large aggregates was found in both limed treatments, and a higher proportion of small aggregates in SL. In barley, grain yield was unaffected while shoot numbers and biomass in first node stage increased for GL and biomass increased further for SL. Structure lime increased potassium concentration in plants in first node stage, due to more potassium in the product. Both lime types increased molybdenum concentration. Ground limestone reduced zinc concentration compared with no liming. Finer seedbed tilth and increased aggregate stability may explain increased biomass for GL. Higher potassium content in SL might be a further explanation. No interactions between liming and fertilisation were found. In conclusion, on the soil types studied, no change of fertilisation strategy is needed due to liming. [ABSTRACT FROM AUTHOR]

A long-term field experiment was conducted from 1989 to 2007 in northern France in a loamy soil to assess the cumulative effects of cropping systems (CSs) on soil compaction, soil porosity, soil structure, crop emergence and yield. Three CSs, including different crop rotations and cultivations (early or late sowing and harvesting), were compared. CS I was the succession of spring pea/winter wheat/oilseed rape (flax from 2001)/winter wheat while CSs II and III were the succession of sugar beet/winter wheat/maize/winter wheat. The latter two CSs consisted of different sowing dates, based on two distinct decision rules aimed at minimizing the risk of soil compaction in the CS II or maximizing the duration of the crop in the CS III. The tillage system was only mouldboard ploughing up to 2000 while a new treatment with superficial tillage (i.e. at 6 cm depth) was integrated since then into the experiment to compare the effects of annual ploughing and reduced tillage on changes in soil structure over time. Soil water content was measured for each field operation by taking samples every 0.05 m up to a depth of 0.30 m in the topsoil. Soil compaction and soil structure was evaluated after each sowing using a morphological approach and soil bulk density measurements. The ‘‘profil cultural’’ method was used to map soil structure variations in the topsoil below the seedbed. Dry bulk density was measured with a gamma-ray transmission probe. Seedling emergence rates and crop yield were also measured in relation to CSs. This dataset represents an important description of the changes in the soil compaction level, crop emergence rates and yield, in relation to CSs and climate, and the overall impact on seedbed structure variations for major field crops under northern France conditions. This information can be used as input variables of several soil-crop models aiming at evaluating the impact of CSs and climate on soil compaction and seedbed structures.

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Decreased frequency but greater intensity of rainfall in semi‐arid India severely affects growth and the yield of rainfed annual food crops, where there is no other source of water, leading to moisture stress during protracted dry spells. As Indian farmers growing rainfed crops are small landholders, their better option is in situ rainwater harvesting. This ensures moisture storage and increases soil moisture available to rainfed crops with less‐costly investment. Accordingly, a field investigation was established over 2011, 2012 and 2013 at the Dryland Agricultural Research Station, Chettinad, India. We studied the effects of seedbed preparation method (SBPM) and mulching with crop residues (CRM) on soil physicochemical properties, growth, yield and yield attributes of groundnut. Greater soil moisture content was measured under compartmental bunding (CB) and raised bed (RB) with CRM than under flatbed (FB). Soil bulk density was considerably smaller under CB and RB with CRM (1.36 and 1.37 Mg m−3) compared with FB (1.39 Mg m−3). Soil microbial biomass carbon (SMBC) was larger under CB and RB with CRM (563 and 542 mg kg−1 soil, respectively) than FB with and without CRM. RB with CRM application contained more soil organic carbon (SOC) stock (3.1 Mg ha−1) than FB. CB with CRM resulted in larger groundnut yield (1,604 kg ha−1) and rainwater use efficiency (5.8 kg ha−1 mm−1) than the FB with and without CRM; RB and RF with CRM were intermediate. The ideal seedbed preparation for groundnut crop in Alfisol under semi‐arid conditions was compartmental bunding (CB) and raised bed (RB) along with CRM. [ABSTRACT FROM AUTHOR]

In order to achieve the construction standard of high mechanized performance of the seedbed with whole plastic-film mulching on double ridges, in this study, the forms of suppression failure were analyzed, and the key factors influencing the suppression performance were determined based on the structure of the seedbed suppression device and its working principles. The discrete element method was adopted for numerical simulation on the suppression process of the seedbed with whole plastic film mulching on double ridges; the parameters during the interaction between the suppression device and seedbed soil were extracted and analyzed, such as contact area, sinkage and horizontal traction resistance trend of press wheels on big ridges and furrows of small ridge. Taking the suppression load on big ridges, suppression load on furrows of small ridge, and advancing velocity of the combined operation machine as the independent variables, qualified rate of suppression as the response value, a mathematical model between the test factors and qualified rate of suppression was established, to explore the influence sequence of the factors on suppression qualified rate. The optimal working parameters of the suppression device were finally obtained: the suppression load on big ridges was 40 N, suppression load on furrows of small ridge was 69.8 N and the machine advancing velocity was 0.98 m/s, and the achieved mean value of suppression qualified rate was 92.6%. Field verification test showed that the mean value of suppression qualified rate was 90.3%, a mere difference of 2.3% compared with the simulation result. The actual operation of the sample machine was basically consistent with the simulation process and could reveal the mechanized suppression operation mechanism of the seedbed with whole plastic film mulching on double ridges, indicating that the established DEM model and its parameter setting were relatively accurate and reasonable. [ABSTRACT FROM AUTHOR]

It is reported in various sources that there are twenty-six zaviye in Ordu region. The Hacıemiroğulları Principality, which conquered the Ordu region, and then the Ottoman Empire, benefited from the Turkification of the lands conquered from these lodges and the spread of Islam there. As a result of the conquest, Turkish tribes coming from Tokat and Niksar started to settle in the region. The dervishes in these tribes led the Turkish tribes both during the journey and in the areas they settled. These dervishes also established zaviye to educate and gather the people in the regions where they settled. One of these zaviye is Sarı Sâdık Seesbed in Yukarı Kızılen Village of Ulubey District of Ordu Province. Although it is not mentioned as a zaviye in the sources, it is included as Sarı Sâdık Evliyası in the records of the registers and in the memory of the local people. Sarı Saltuk is also known as Sarı Saltık and Sarı Sâdık in the Turkic world and is a dervish loved by the people for leading the entry of Islam to the Balkans and the Turkification of these regions in the second half of the 13th century and many legends are told about him. It is told that Sarı Saltuk has twelve tombs in Saltukname. Apart from these tombs, the name Sarı Sâdık is also mentioned in the Karye-i Kızılin section in the registration book of the Ordu region dated 1455 and 1485. It is registered that he had land and paid taxes during this period. In addition to these records, other information about Sarı Sâdık can be obtained from the narratives of the local people. As it is understood from the narratives, the place known as Sarı Sâdık is described as a seedbed by the local people and is used as a place to visit for relief from illness, wishes and prayers. In this study, an unknown Sarı Sâdık Seedbed in Ordu was investigated and tried to be brought to light with the information obtained from historical sources and local people. [ABSTRACT FROM AUTHOR]

The present work was developed with the aimed to evaluate the application of worm's humus in the production of seedlings of tomatoes (Lycopersicon esculentum Mill) cultivar Roma, in the rural settlement San Isidro-San Ignacio, municipality of Tinaquillo, State of Cojedes, Republic of Venezuela. Five treatments were studied: chemical fertilization (control), worm`s humus at 4 t ha-1 bottom, worm`s humus at 4 t ha-1 bottom + worm`s humus leaching above foliage at 15 days of seeds germination, worm`s humus at 6 t ha-1 bottom and worm`s humus at 6 t ha-1 bottom + worm`s humus leaching (1L per 50 L water) above foliage at 15 days of seeds germination. The experimental design was a random block with three replications. After 25 days seed germination it was measured the plant height, number of leaves per plant, stem diameter, root length, fresh and dry mass of leaf and root. The higher values obtained in each one of the studied parameters during tomatoes plant growing were achieved with the application of 4 t ha-1 worm`s humus at bottom plus worm`s humus leaching (1L por 50 L water) above foliage at 15 days after seed germination.

Highlights • Low levels of seedling recruitment were found in shelterwood-treated jarrah forest. • Recruitment was strongly linked to levels of canopy seed store and seed fall. • A minor positive effect of ashbed, particularly areas burnt to mineral soil, was found. • Adequate seedling recruitment following logging in jarrah forest may require more intense fire. Abstract Successful and adequate recruitment of seedlings is an essential ecological process in forest ecosystem dynamics and is a key principle underpinning sustainable timber harvesting. This is particularly so with the shelterwood silvicultural system used in the jarrah (Eucalyptus marginata) forest of south-west Australia where partial cuts of overstorey are made followed by prescribed burning to stimulate seed fall and seedling establishment. There have been concerns over the lack of seedling recruitment in some shelterwood-treated areas of the jarrah forest, and hence this study was implemented to explore the roles of seed supply and seedbed conditions in limiting recruitment of jarrah seedlings. Low seedling densities were recorded across all six burnt study sites and were strongly correlated (at both broad and fine scales) with both canopy seed store and seed fall. Ample levels of post-burn seed fall only resulted in low seedling numbers suggesting that adequate seed supply did not coincide with seedbed conditions suitable for mass seedling regeneration. Conditions favourable for seedling recruitment were highly variable within sites, since both seed supply and seedbed conditions were spatially heterogeneous. Fine-scale areas burnt to mineral soil showed an additive influence to the overwhelmingly dominant factor of seed supply on seedling recruitment. However, the capacity of low intensity burns to produce these seedbed conditions at a broad scale appears to be limited. Results suggest that successful stocking of shelterwood-treated jarrah forest is not always feasible following a single silvicultural event, such as post-harvest burning under mild conditions. The chances of ample seed supply coinciding with broad-scale seedbed conditions favourable for mass germination, emergence and establishment appear to be low. Successful stocking of shelterwood-treated jarrah forest is more likely to be a longer term outcome achieved through episodic recruitment, especially when favourable environmental conditions coincide with optimal seedbed conditions. Such episodic recruitment strategies may be common in resource-limited systems such as jarrah forest and other dry eucalypt forest systems, where conditions controlling the regeneration niche are often variable and unpredictable. [ABSTRACT FROM AUTHOR]

Research highlights: To understand differences in the establishment of balsam fir regeneration observed in the boreal forest, we examined how soil layer and microorganisms explained differences in growth and mycorrhization in three different stand types. Our experiment revealed positive and negative effects on growth of seedlings, and highlights the importance of biotic interactions in balsam fir establishment. Background and Objectives: In a context of climate change, understanding tree migration can be examined through changes in tree regeneration. At the ecotone between mixed and conifer boreal forest, regeneration of balsam fir northward is of particular interest because it thrives better under aspen-dominated stands as compared to adjacent spruce-dominated stands. As the understorey differs between these stands, with more Ericaceae under spruce and different ectomycorrhizal fungal communities in organic and mineral horizons, we hypothesized that biotic factors could explain differences in balsam fir establishment. Materials and Methods: Using a growth chamber experiment, we tested if differences in soil layers and modification of soil fungal communities would affect germination, mycorrhization, and growth of balsam fir seedlings in three different stand vegetation. We compared 12 treatments and followed 120 seedlings over three growth seasons. Results: We found similar survival in soils from aspen- and spruce-dominated stands, and a greater biomass on organic layers. In addition to this, a greater mycorrhization rate was found in aspen soils but improved germination in spruce soils. The presence of Ericaceae in spruce soils was associated with lower mycorrhization but did not affect other traits. Sterilization and therefore microorganisms affected mainly the number of ectomycorrhizae and the investment in root biomass. Finally, mycorrhization and biomass were correlated, but independent from N nutrition measured in needles. Conclusions: Our results highlighted the positive effects of organic soil layers and of mycorrhization on biomass, and showed that mycorrhization was increased under aspen as compared to other stand types. Our experiment also revealed positive effects of spruce soil on fir germination and showed that fir was able to grow and survive in all conditions. Our study suggests that fir establishment is affected by belowground multi-species interactions, and therefore highlights that biotic interactions shall be taken into account to understand and predict future tree migrations in the boreal forest.

Experiment was conducted in 2011 to evaluate the efficacy of reduced herbicide rates in combination with false seedbed for selective weed control in common bean. The experiment was carried out with a completely randomized factorial design. Factors were herbicide dose (post-emergence application of imazethapyr at the rates of 0, 25, 50, 75, and 100 g a.i. ha-1) and seedbed preparation (false seedbed and conventional seedbed). A hand weeding control was also included as check. In the absence of herbicide, there were significant differences in grass and total weeds biomass between two seedbeds (p< 0.01), however, biomass of broadleaved weeds was not significantly different in two seedbeds (P=0.053). The false seedbed decreased grass and total weed biomass by 28 and 21%, respectively, as compared with conventional seedbed. Imazethapyr application greatly affected grass and broadleaf weed growth and biomass production. The rate of 50 g a.i. ha-1of imazethapyr was as effective as the 100 g a.i.ha-1 rate to maintain consistent weed control in the false seedbed, while, the rate of 75 g a.i. ha-1 was required to maintain effective weed control in conventional seedbed. Season-long weed competition resulted in 68 and 73% yield loss in common bean in the false and conventional seedbed, respectively. However, imazethapyr application decreased yield loss down to 4.7 and 2.9% in false and conventional seedbed, respectively. The study suggests that acceptable weed control in common bean of the weed species observed in the present study could be achieved using imazethapyr at the rate of 56 g a.i. ha-1 in combination with false seedbed, which can save the yield by 90%.

Background: Global agriculture is undergoing a phase of agroecological transition. This transition will be characterized by adoption of agroecological cropping practices and by an increased diversity of soil management/tillage practices. However, very little is known as to whether or not crop seed germination and seedling emergence (hereafter referred to as SGE) will be affected under these cropping practices.Scope: This paper first proposes a conceptual scheme which integrates key abiotic and biotic factors affecting crop SGE. Subsequently, the key mechanistic factors affecting SGE (i.e. intrinsic factors related to the seeds, and extrinsic factors related to the biotic and abiotic conditions of the seedbed), and how crop management practices can influence SGE through alterations of these direct mechanistic factors are discussed. This is done with special emphasis on how agricultural practices, particularly those related to agro-ecology, may impact SGE.Conclusions: Crop SGE are affected by five major groups of drivers, namely seed and seedling characteristics, seedbed physical components, seedbed chemical components, seedbed biological components, and cropping systems. Although the crop SGE failure frequently occurs under field conditions, very little quantitative information is available in the literature on the real economic impact, the precise cause/s and ranking of factors associated with this failure. Re-seeding is often practiced for a number of crops to compensate the lack of SGE with significant direct and indirect costs for farmers. Little information exists in the literature concerning how SGE will be affected under agroecological cropping systems, such as conservation agriculture, or organic farming, or under climate-driven changes. Field observation, experimental and modeling studies are needed to fill the current knowledge gaps on the economic impact, precise cause/s and ranking of different stress factors associated with SGE failure. [ABSTRACT FROM AUTHOR]

Species in cold-limited biomes are expected to expand their distribution ranges in response to climate warming. For plants, range shifts can only occur via successful recruitment beyond their current distribution limit. However, many environmental and ecological filters can act upon recruitment and establishment, thereby potentially limiting the expected climate-driven shifts. In this study, we investigate potential mechanical and chemical constraints that vegetation above the tall shrubline in alpine and Arctic tundra could impose upon the successful establishment of willow species in the Canadian Western Arctic. We collected willow seeds from an alpine and an Arctic shrubline and conducted germination trials to test (1) for seedbed preferences among three natural and one experimentally scarified seedbeds, and (2) for vulnerability to allelopathic chemicals produced by ericaceous dwarf shrub species. We found that germination was almost four times higher on manually exposed bare ground than on intact, herbaceous vegetation. Seeds of two willow species, Salix arctica and Salix pulchra, were not affected by leaf extracts from dwarf shrubs, Cassiope tetragona and Vaccinum uliginosum, but the germination of Salix richardsonii was reduced by as much as 24% in the presence of chemicals from C. tetragona. Our results suggest that biotic interactions could limit the predicted expansion of tall shrubs in the tundra by interfering with germination. Seemingly species-specific responses highlight the need for replicated studies across a wider range of species combinations. Potential range shifts may not occur as a uniform translocation of the shrubline, but could change the composition of the plant community by filtering out certain species. [ABSTRACT FROM AUTHOR]

Seed–soil contact plays an essential role in the process of germination as seeds absorb water through direct contact with the moist soil aggregates that surround them. Factors influencing seed–soil contact can be considered as those pertaining to soil physical properties (e.g. texture, bulk density, porosity, etc.) and those related to environmental conditions (e.g. temperature, rainfall, frost). Seed–soil contact is furthermore influenced by the specific field management processes that farmers apply, which have developed significantly over the last 30 years. However, the precise effect of cultivation on the actual contact area of the seed with the surrounding soil is based on a series of assumptions and is still largely unknown. This review considers the influence of soil management and its direct impact on seed–soil contact and establishment. We review the state of the art in methodology for measuring seed–soil contact and assess the potential for soil amendments such as plant residues and waste materials to improve seed–soil contact. Engineering the 'optimal' seed–soil contact remains a challenge due to the localized variation between the interaction with field management techniques and soil texture, climatic conditions and crop type. The latest imaging approaches show great promise to assess the impact of management on germination. Combining the techniques with the latest network models offers great potential to improve our ability to accurately predict germination, emergence and establishment. [ABSTRACT FROM AUTHOR]

Wet thermal germination regression models predict when subpopulations of seeds will germinate based on the summation of thermal time when seedbed soil water potential > −1.5 MPa. Germination rates fit models well at temperatures greater than 5 °C and less than 25 °C, but may not fit as well outside of that range. To better determine accuracy of these models, we quantified and compared seasonal wet degree days (WDD – a measure of thermal time) of sagebrush ( Artemisia L.) -steppe seedbeds at five temperature ranges for up to 9 yr across 24 sites. Estimated thermal effects of three piñon and juniper ( Pinus spp. and Juniperus spp.) tree removal treatments and three woodland infilling phases at time of tree reduction were also compared. We found that seedbeds sum a majority of WDD between 5 °C and 25 °C. Exceptions amounted to a relatively small percentage (12–20%) of total WDD in a season. Tree infilling or removal added WDD at 0 to <5 °C and 25 to <30 °C on a few sites, but germination models should still be accurate enough to predict germination for many sagebrush steppe sites and also predict the effects of vegetation manipulations on germination potential. [ABSTRACT FROM AUTHOR]

Natural regeneration of Norway spruce (Picea abies (L.) Karst.) is a relatively common practice in Norway on medium to low site indices. However, seedling establishment is often hampered by rapid regrowth of competing vegetation in scarified patches. The aim of our study was to examine the effect of coordinating scarification towards an expected seed-fall, by studying germination and seedling establishment in scarified patches of different age (fresh, one- and two-year-old). The experiment was conducted in two stands in southeast Norway that were clear-cut in 2007. Scarification was applied to subplots in autumn 2008–2010. To simulate seed-fall, seeds were sown in fresh scarification patches in spring 2009–2011, in one-year-old patches in 2010 and 2011, and in two-year-old patches in 2011. Both germination and seedling survival were negatively affected by the age of the scarified patches. Germination was higher, and mortality lower, at the small fern woodland site, compared with the bilberry woodland site. Sowing in fresh patches also resulted in increased height and root collar diameter of the seedlings compared with sowing in older patches. It is likely that the competing vegetation both on the site and in the scarification patches affected the growth of the seedlings. In conclusion, the age of the scarified patches affected both germination and mortality, as well as early growth of the seedlings. [ABSTRACT FROM AUTHOR]

The introduction of a new and operational system to control weed which can improve application flexibility and control troublesome and stubborn weeds in sugar beet crop. A field study was designed to evaluate the combination of chemical and non-chemical management on cuscuta infestation in sugar beet field. Delaying sowing until the April 18 altered fresh weight of sugar beet 46.1 and 34.9% in the same seedbed preparation in autumn and spring, respectively. Also, application of pyropyzamide herbicide caused the significant difference and greater decrease in weight of cuscuta weed in comparison to another herbicide, ethofumesat. Spring seedbed preparation was more efficient in suppressing and inhibition of cuscuta weed growth than winter seedbed preparation. The concentration of recommended herbicide+25% more treatment showed severity control of cuscuta weed. So, sustainable management of cuscuta inhibition will require a combination of chemical and cultural approaches, supported by understanding the complicated and unclear nature of cuscuta life cycle. [ABSTRACT FROM AUTHOR]

Research Highlights: Regenerating northern white-cedar (Thuja occidentalis L.) is challenging throughout much of its range. This study attempts to relate differences in natural regeneration to stand- and seedbed-level factors. Background and Objectives: Lack of regeneration of northern white-cedar is often attributed to overbrowsing by white-tailed deer (Odocoileus virginianus Zimmerman) because white-cedar is a preferred winter browse species. However, there are many other factors that may contribute to regeneration failure for white-cedar including its specific seedbed requirements and competition from other, often faster-growing trees and shrubs. Materials and Methods: We surveyed five mature white-cedar stands in Wisconsin, USA that have had little to no management in the past 50+ years to find stem densities of natural white-cedar regeneration in three height classes. We also collected data at each stand on potential predictor variables including overstory attributes, competitive environment, seedbed, and browsing by deer. We used model selection to create separate models to predict stem density of each white-cedar regeneration height class. Results: None of the measures of deer browsing used in this study were found to be associated with white-cedar regeneration. Soil pH, competition from other seedlings and saplings, and stem density of white-cedar in the overstory were found to be potentially associated with white-cedar regeneration. Conclusions: While browsing by deer is likely a factor affecting white-cedar regeneration in many areas, this study highlights the challenge of quantifying deer browse effects, as well as showing that other factors likely contribute to the difficulty of regenerating white-cedar.