Grass Cover Crop Research Articles

Plant organ rather than cover crop species determines residue incorporation into SOC pools

The implementation of cover crops has emerged as a promising approach to improve soil organic carbon (SOC) stocks, with particular emphasis on the perceived higher carbon use efficiency displayed by high-quality residues such as from leguminous plants. In this study, we explored how different cover crop residues, specifically from a legume and a grass cover crop, affects SOC formation and its distribution across various soil carbon pools. Over a 7-month period, we incubated 14C-labeled winter rye and hairy vetch residues in microcosms containing soils of varying soil fertility levels from a long-term field trial. We tracked the fate of carbon into free and occluded particulate organic matter (fPOM, oPOM), mineral-associated organic matter (MAOM), and carbon deposited outside the detritusphere.Despite notable differences in C:N ratio, chemical composition, and turnover rate, similar SOC formation efficiency between vetch and rye within each plant organ (shoots and roots) was observed. Interestingly, the plant organ appeared to exert a greater influence on the fate of cover crop carbon than whether the crop was leguminous or non-leguminous. This phenomenon seemed to be closely related to the lignin content.At medium soil fertility, we found that the largest proportion of cover crop residue C remained as MAOM (20% for shoots, 15–18% for roots), followed by fPOM (5–6% for shoots, 10–12% for roots) and oPOM (2.7–3.0% for shoots, 1.5–1.6% for roots). Notably, fPOM and oPOM exhibited opposite responses to residue quality, indicating functional distinctions between these often-pooled POM pools.Soil fertility exerted minimal influence on overall respiration rate patterns or SOC formation, although it did affect oPOM formation efficiency, likely due to differences in soil aggregation.In conclusion, our findings challenge the assumption regarding the superiority of N rich leguminous cover crop residues for enhancing SOC accrual in C pools believed to have longer persistence.

Soybean performance under the biomass of Quênia guinea grass cover crops after intercropping with maize

Soil cover biomass in integrated systems can improve agronomic characteristics and impact in soybean productivity. Thus, the objective is to evaluate the desiccation efficiency, biomass production, nutrient accumulation, and soybean productivity in Quênia guinea grass (Panicum maximum cv. BRS Quênia) biomass after with an intercropped with maize in different forms of seeding, in compare the conventional soybean. The experimental design was a randomized block with four replicates. The treatments consisted of cover crop biomass: maize monoculture; Quênia guinea grass monoculture; maize intercropped with Quênia guinea grass within rows; maize intercropped with Quênia guinea grass between rows and an additional soybean treatment without cover biomass. The results showed that the Quênia guinea grass in the different cropping systems presented high desiccation efficiency, showing potential as a cover plant in integrated systems. The intercropping system of maize with Quênia guinea grass between rows is more recommended than seeding in the same rows as maize, because it promotes greater biomass production and nutrient cycling, reflecting in higher soybean productivity. The integrated production systems is a promising and efficient technology for production systems compared to the system of monoculture maize and soybeans without soil cover biomass, which ensures greater sustainability of agricultural systems.

Effects of Fall and Winter Cover Crops on Weed Suppression in the United States: A Meta-Analysis

Cover cropping recently emerged as a promising alternative to conventional tillage and herbicide use for weed suppression in agricultural systems. We investigated their effectiveness in weed control and the varying effects of different management strategies using a meta-analysis. Our analysis studied two categories: weed biomass control and weed density control. We employed a random-effect model to analyze weed biomass to address between-study heterogeneity and found that cover crop treatments led to a significant 62.6% reduction in weed biomass. These results are robust to outliers and publication bias. Furthermore, subgroup analysis found that planting a mixture of cover crop types was more effective than planting a single type. Additionally, planting a mixture of cover crop species, which are subcategories of cover crop types, was found to be more effective than planting a single species. Our analysis also unveiled a persistent, albeit diminishing, reduction in weed biomass even after the termination of cover crops. For weed density analysis, we used a fixed-effect model due to the absence of between-study heterogeneity and found a statistically significant reduction (45.4%) in weed density. Subgroup analysis revealed no significant difference in weed density control between legume and grass cover crop types.

Grazing summer cover crops mix impact on carbon[sbnd]nitrogen cycling, soil water, and wheat yields

Summer fallow practice is common in the US semiarid Southern Great Plains ecoregion. Its primary objective is to store water to enhance winter wheat production for grain and grazing. Prior research on replacing fallow with legume cover crops (CC) (green manure) reported a yield loss through soil moisture depletion for winter wheat. Recent research has shown the potential of grass CC to enhance soil physical properties compared to legume CC. Cost-benefit analyses of CC make it difficult to justify their adoption. Grazing, however, offers an opportunity to mitigate CC costs. The impact of a grazed CC mix on stored soil water, CN cycling, intercropping, and wheat yields was evaluated. Although CC used soil moisture early in the growing season and nitrate+nitrite-N, they recharged soil moisture by the critical wheat seeding and dormancy-breaking periods. In the summer of 2014, net mineralization in CC increased nitrate+nitrite-N by 10-fold compared to 2013 concentrations, resulting in no significant differences in yields in 2015. Nitrate+nitrite-N was reduced by 28% in 2015 compared to the preceding year due to CC growth and net nitrate+nitrite-N immobilization in residues, resulting in 25% less yield in CC treatments in 2016 compared to no-till (NT) fallow. Grazed and ungrazed CC enhanced organic N by up to four times that in NT fallow and sequestered particulate organic N and C by 7–17% and 6–10%, respectively, in micro-aggregates. Despite reducing biomass by 56%, grazing did not differ from most ungrazed measured soil parameters, offering the potential for mitigating CC production costs.

Tradeoffs when interseeding cover crops into corn across the Chesapeake Bay watershed

CONTEXTIn annual cropping systems at high latitudes, an early onset of winter limits the establishment of cover crops in fall and ultimately the ecosystem services they provide such as nitrogen (N) leaching reduction. Interseeding cover crops into a standing cash crop can improve establishment before winter, but its practice is limited in both scope and scale. OBJECTIVETo identify tradeoffs and establish regional patterns of interseeding success in the environmentally sensitive Chesapeake Bay Watershed of North America, we used the agroecosystem model Cycles to compare in silico systems in which cover crops were either interseeded into a standing crop of corn (Zea mays L.) or conventionally seeded after corn harvest. METHODSIn each of the 153 counties contained in the Chesapeake Bay Watershed, a representative field was simulated and either seeded with ryegrass (Lolium perenne L.), a blend of legumes, or a mix of legumes and ryegrass in a continuous corn sequence. The simulated corn yield, cover crop biomass production, N leaching reduction, and total N losses were compared between the cover crop scenarios and a monoculture corn control. RESULTS AND CONCLUSIONSSimulations showed that conventionally seeded cover crops did not affect corn yields of the following year. However, when interseeded, the drag on corn yield in the same year averaged 6% per Mg of fall cover crop biomass. The corn yield reduction notwithstanding, interseeding reduced N leaching by 10% for legumes, 25% for the mix, and 50% for solo ryegrass compared to the no cover-crop control. There are other tradeoffs, such as an offset of N fertilizer inputs from N2 fixation when using legumes despite the less effective nutrient capture. Regardless of the cover crop type, interseeding up to latitude 41° N tends to be competitive with the cash crop, but north of that threshold (or west into higher elevations) the mitigation of N leaching when interseeding seems to outweigh agronomic costs. SIGNIFICANCEThis study provides useful insight into watershed-scale agronomic and environmental processes without the constraints of establishing large-scale networks of field trials. Given these analyses, future field research in areas suitable for interseeding can focus on establishing legume cover crops in high-yielding fields with low residual mineral N, grass cover crops in manured or low-yielding fields with residual mineral N, and a mixture of both when N supply is uncertain and preventive management is needed.

Winter cover crops to reduce herbicide inputs into spring-planted maize pastoral systems in New Zealand

ABSTRACT The use of cover crops can improve the environmental sustainability of intensive cropping systems. A five-year field trial was undertaken to evaluate the effect of multi-season cover cropping on weed suppression within a no-till spring-planted maize system in the Waikato region in New Zealand. Five cover crop treatments were compared: gland clover (Trifolium glanduliferum Boiss.); faba bean (Vicia faba L); oats (Avena sativa L.); and Italian ryegrass (Lolium multiflorum Lam.), and winter fallow. The results demonstrated that in this system, herbicide treatments can be reduced to one application to terminate the winter cover crop and a single maize post-emergence application, thus reducing selection pressure for herbicide-resistance, without any loss in silage or grain production. Furthermore, a legume-based cover crop gave higher yields than the grass cover-crops and reduced the damage by the maize and grass pest cosmopolitan armyworm (Mythimna separata Walker). The build-up of crop residue over time was detrimental to the establishment of the small-seeded clover and ryegrass cover crops but good weed suppression and grain yields were achieved in the final season by replacing them respectively with the larger seeded woolly pod vetch (Vicia eriocarpa (Hausskn.) Halácsy) and a blue lupin (Lupinus angustifolius L.)/ mustard (Sinapis alba L.) mix.

Soil fertility and pomelo yield influenced by soil conservation practices

Abstract Exchangeable cations and soil nutrients leach out/lost in the raised bed soils system through irrigation water and rainwater. Cover crops or crop residue mulching are considered sustainable agricultural measures because they prevent soil degradation and compaction and increase the soil ecological diversity. However, the impact of these on soil quality in fruit orchards in the Vietnamese Mekong Delta is not well studied. The present work aimed to assess the effect of cover crops (grass, pinto peanut) and rice straw mulching on change in soil chemical properties and productivity of pomelo. The 3-year (2019–2021) field experiment was conducted at Phu Huu Commune, Chau Thanh District, Hau Giang Province, Vietnam. Four treatments, control (no-cover crop), grass cover crop, mulching with rice straw (MRS), and pinto peanut cover crop were used. Soil samples were collected from the depth of 0–20 and 20–40 cm for analyzing soil pH, total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), and soil organic matter (SOM). Results showed that MRS or cover crop by pinto peanut significantly decreased soil acidity in the topsoil layer. Soil fertility properties (TN, TP, AP, and SOM) at the depth 0–20 cm were greatly improved after the application of the mulched rice straw and cover crop by legume, thus improving pomelo yield. Further study is required to understand the effects of the cover crop with pinto peanut and rice straw mulching on the physical and biological properties of soil as well as nutrient uptake of pomelo orchards.

A grass–legume cover crop maintains nitrogen inputs and nitrous oxide fluxes from an organic agroecosystem

AbstractLegume cover crops are central to an ecological nutrient management approach that can reduce nitrogen (N) losses from agriculture. Diversifying cropping systems with a legume–grass cover crop mixture could further reduce N losses by increasing soil N assimilation and synchronizing N mineralization with N uptake by the following crop. We established four winter cover crop treatments (crimson clover, cereal rye, clover–rye mixture, and weedy fallow control) in an organic grain agroecosystem that had been managed for 30 years with a legume cover crop as the only external N source. We hypothesized that the legume–grass mixture would provide similar inputs of biologically fixed N2 compared with the sole legume, while reducing N2O emissions during decomposition following tillage. We measured cover crop aboveground biomass C:N and clover N2 fixation, soil inorganic N and N2O fluxes throughout the corn growing season following cover crop tillage, and corn N assimilation at harvest. Even with a reduced clover seeding rate in mixture, the clover and mixture treatments had similar fixed N inputs, litter N and C:N, and no differences in cumulative N2O emissions. During the first peak flux, N2O emissions were 2–5 times higher in clover and mixture relative to rye and fallow, with no differences between clover and mixture. There were no treatment differences at the second N2O peak, which followed the first major rain event. We contextualized these findings by calculating a 6‐year partial N mass balance for this agroecosystem, which was slightly negative (−6.8 ± 0.8 kg N ha−1 year−1) when accounting for historical mean annual N2O emissions and nitrate leaching. Overall, N inputs and harvested N exports were approximately in balance for this legume‐based crop rotation, suggesting that the legacy of ecological nutrient management has promoted efficient N cycling. However, results from our field experiment indicate that short‐term N2O flux rates following cover crop incorporation can be high even for a legume–grass mixture. Additional strategies to reduce soil disturbance are therefore needed to further tighten N cycling in organic grain agroecosystems.

Long-term C and N sequestration under no-till is governed by biomass production of cover crops rather than differences in grass vs. legume biomass quality

Agricultural activities through conventional and intensive practices contribute to climate change by increasing emission of reactive carbon (C) and nitrogen (N) from soils to the atmosphere. Minimum soil disturbance, appropriate residue management and cover cropping as conservation practices are perceived as key strategies to limit GHGs emissions by increasing soil C and N sequestration as soil organic matter (SOM), thus promoting soil aggregation and enhancing soil fertility. Yet, the actual contribution of conservation practices to C and N sequestration, as well as mechanisms behind chemical and biochemical stabilization of SOM in the long-term are still controversial. In the present 9-year field study on a wheat-maize-soybean rotation we investigated the effect of no-till (NT) coupled with grass vs. legume cover crop (i.e., rye [Secale cereale L., NT-R] or hairy vetch [Vicia villosa Roth, NT-V]) on main crop yields, C and N input by cover and main crops, soil aggregation and C and N sequestration rates, in comparison with conventional tillage (CT). We hypothesized that NT-R may lead to higher biomass input, C sequestration and comparable yield to CT, while NT-V may increase N input, N sequestration and lead to comparable yield to CT. We found that yield of winter wheat, maize, and soybean were never reduced under both NT treatments, neither during the transition phase, nor afterwards. Rye and hairy vetch provided the same amount of biomass and C input, although vetch doubled N input compared with rye. Moreover NT-V increased cumulative biomass and C input from main crop residues compared with NT-R. Both NT-R and NT-V promoted C (+0.4 Mg ha−1 y−1 and +0.6 Mg ha−1 y−1, respectively) and N (+88 kg ha−1 y−1 and +145 kg ha−1 y−1, respectively) soil sequestration, mainly due to the increase of macroaggregate-associated C and N, thus corroborating a major role of NT for macroaggregates formation and SOM stabilization within macroaggregates. Since no difference was found between cover crops in terms of biomass input, and C and N sequestration potential, we concluded that cover crop biomass production (rather than biomass quality) and retention onto the soil as residue were the main drivers of soil C and N sequestration. Therefore, both rye and hairy vetch may be combined with NT and promise significant potential as effective C farming practices.

Influence of rye/oat cover crop in a two‐year soybean production system

AbstractAs the cost of corn (Zea mays L.) production increases, some farmers find continuous soybean [Glycine max (L.) Merr.] to be more profitable than corn–soybean rotation. However, a grass cover crop could help diversify the cropping system. The study objectives were to evaluate planting date and termination timing of a rye (Secale cereale L.)/oat (Avena sativa L.) cover crop mix on cover crop biomass and soybean disease, insects, slugs, and grain yield within a 2‐yr soybean production system. Field trials were conducted in 2018 and 2019 at two locations in Ohio (northwestern and western). The main plot factor was cover crop planting date (September through October) and the subplot factor was cover crop termination timing (2 and 4 wk prior to soybean planting). Cover crop planting date and termination timing had little influence on soybean diseases and insects. Soybean grain yield was influenced by cover crop termination timing at the northwestern location. In 2018, soybean yield was 4% greater when the preceding cover crop was terminated late and in the control (no cover crop) compared to early cover crop termination. The following year, soybean yield was 8% greater when the cover crop was terminated late compared to early termination and the control. At the western location, there was no impact of cover crop termination timing on yield. Late‐terminated cover crops had a positive effect or no effect on yield of the following soybean crop.

Ring‐necked pheasant nest site selection in a landscape with high adoption of fall‐seeded cover crops

AbstractGrasslands provide important nesting cover for ring‐necked pheasants (Phasianus colchicus), but they have been largely reduced with intensification of row‐cropping systems, resulting in population declines for pheasants and other grassland birds across the U.S. Row‐crop intensification and landscape homogenization has had negative impacts on environmental health, and agronomic practices such as fall‐seeded cover crops seek to ameliorate some of the environmental issues. Whether fall‐seeded cover crops provide additional benefits to wildlife, such as creating nesting cover for pheasants, remains unknown. We used radio telemetry and nest searches in 365, 0.4‐ha² plots during summer of 2019 and 2020 in 3 cover types including fall‐seeded cover crops, native warm season grasses, and cool season grasses to examine nest site selection by pheasants in the agricultural dominated landscape of Washington County, Iowa. We examined nest site selection at 3 spatial scales based on cover type and specific vegetation attributes to understand factors influencing nest site selection. Highest nest densities were found in native warm season grass (0.59 nests/ha, 95% CI = 0.41–0.86), while pheasants nested at low densities in cool season grass fields (0.03 nests/ha, 95% CI = 0.00–0.21) and cover crop fields (0.03 nests/ha, 95% CI = 0.01–0.12). Most nest‐site selection occurred at the landscape level (second order) and patch level (third order) and was influenced by percent litter cover (second order) and visual obstruction or vegetation density (third order). Our findings suggest that cover crops may make minor improvements in nesting cover availability but are unlikely to replicate the needs for nesting cover provided by perennial grasslands in working landscapes and thus have little potential to reverse long‐term population declines.

Episodic N2O emissions following tillage of a legume–grass cover crop mixture

Abstract. Nitrogen (N) fertilizer inputs to agricultural soils are a leading cause of nitrous oxide (N2O) emissions. Legume cover crops are an alternative N source that can reduce agricultural N2O emissions compared to fertilizer N. However, our understanding of episodic N2O flux following cover crop incorporation by tillage is limited and has focused on single-species cover crops. Our study explores whether increasing cover crop functional diversity with a legume–grass mixture can reduce pulse emissions of N2O following tillage. In a field experiment, we planted crimson clover (Trifolium incarnatum L.), cereal rye (Secale cereal L.), a clover–rye mixture, and a no-cover control at two field sites with contrasting soil fertility properties in Michigan. We hypothesized that N2O flux following tillage of the cover crops would be lower in the mixture and rye compared to the clover treatment because rye litter can decrease N mineralization rates. We measured N2O for approximately 2 weeks following tillage to capture the first peak in N2O emissions in each site. Across cover crop treatments, the higher-fertility site, CF, had greater cover crop biomass, 2-fold-higher aboveground biomass N, and higher cumulative N2O emissions than the lower-fertility site, KBS (413.4±67.5 vs. 230.8±42.5 g N2O-N ha−1; P=0.004). There was a significant treatment effect on daily emissions at both sites. At CF, N2O fluxes were higher following clover than the control 6 d after tillage. At KBS, fluxes from the mixture were higher than rye 8 and 11 d after tillage. When controlling for soil fertility differences between sites, clover and mixture led to approximately 2-fold-higher N2O emissions compared to rye and fallow treatments. We found partial support for our hypothesis that N2O would be lower following incorporation of the mixture than clover. However, treatment patterns differed by site, suggesting that interactions between cover crop functional types and background soil fertility influence N2O emissions during cover crop decomposition.

Impact of Cover Crop Planting and Termination Dates on Arthropod Activity in the Following Corn.

Relative to fallow-cash crop rotations, the addition of a cover crop can contribute to greater plant diversity and has the potential to conserve predatory arthropods. The transition of arthropods from a cover crop to a subsequent cash crop depends on several factors, such as cover crop biomass production and weather conditions. Information about the effect of cover crop planting and termination dates on arthropods in a subsequent corn system is limited. A two-year field study was conducted in Nebraska in 2018/2019 and 2019/2020 to evaluate the impact of cover crop planting and termination dates as a source for arthropods in the subsequent corn. A total of 38,074 and 50,626 arthropods were collected in the first and second year, respectively. In both years, adding a grass cover crop increased predatory arthropods but reduced yield in follow corn crop. Of the arthropods collected, Carabidae and Araneae had greater activity with cover crop biomass increments, whereas Collembola and Acari activity only increased in treatments with little or no cover crop biomass. Insect pest pressure was not significant in any treatment for either year. A cover crop planted in mid- or late-September and terminated at corn planting was identified as the best management strategy to maximize cover crop biomass, increase predator activity, and modify predator-prey dynamics. The results of this study provide growers with a cover crop management strategy to maximize cover crop biomass, beneficial arthropod activity, and potentially minimize insect pest problems; however, corn Zea Mays (L.) grain yield was reduced as cover crop biomass increased.

ARAHAN PENGGUNAAN LAHAN BERDASARKAN KELAS KEMAMPUAN LAHAN DI DAS PANGKAJENE BAGIAN HULU DESA LANNE KECAMATAN TONDONG TALLASA KABUPATEN PANGKEP

Land use must meet the requirements necessary for the land to be productive and not be damaged for an indefinite period of time. Transfer of land use is one of the causes of damage to watersheds (DAS), causing complex physical, economic and social problems both upstream and downstream. Land resources in the upstream watershed (DAS) are easily degraded due to erosion. Therefore, the management of land resources in the upstream watershed has an increasingly important role, especially in efforts to use it in a sustainable manner. This research is descriptive qualitative. The data obtained were based on purposive sampling, for each land use and were analyzed based on the land capability classification criteria. The results showed that the Pangkajene watershed upstream of Lanne Village, Tondong Tallasa District, Pangkep Regency has five land uses, namely Protected Forest with ability class VII, rice fields, gardens and shrubs with ability class VI and settlements with land capability class IV. The suitable land uses in the land capability class are Protection Forest and shrubs. Incorrect land use, namely rice fields, gardens and settlements. Unsuitable land use, namely rice fields and gardens, is directed towards land rehabilitation, while settlements are directed to use conservation techniques in the form of leveling the land on a sloping location and mixed garden settlements with moderate density in the form of fruit plants interspersed with grass cover crops. The process of this activity is carried out by still following the pattern of community activities and the principles of soil and water conservation to increase benefits both economically and ecologically

Interactive effects between cover crop management and the environment modulate benefits to cash crop yields: a meta-analysis

Several governmental programs have been established throughout Canada to foster agriculture sustainability. As a best management practice, cover crops (CCs) limit soil erosion and prevent nutrient losses in agroecosystems. Yet, the variable effects of CCs on cash crop productivity previously reported may limit their large-scale adoption by farmers. To address this variability, we conducted an unweighted meta-analysis including 2274 observations from 86 field studies conducted under humid temperate climate to evaluate yield response to CCs for three annual cash crops. Overall, CCs increased corn and small grain cereal yields by 13% and 22% respectively, but did not affect soybean yield. Legume CCs alone or mixed with grasses provided the highest small grain cereal and corn yield increases compared with non-legume broadleaf and grass CCs. CC benefits increased with nitrogen (N) content in CC aboveground biomass but decreased when N fertilizer inputs applied to corn exceeded 60 kg N ha−1. Greater precipitation and N fertilizer inputs reduced the negative effect of grass CCs on corn yield, while benefits of legume CCs were highly resilient to precipitation variations. CC benefits on corn yield increased through time and at low soil organic matter content, especially at low N fertilizer inputs. These results evidence the complex interplay between cash crop productivity, CC management, and environmental factors — related to N inputs from CCs, changes in soil properties (e.g., increased organic matter, improved soil structure or microbial activity), or potential competition for water under drier conditions — which provide new perspectives to promote CC inclusion in cropping systems.

Overseed timing of ryegrass and cereal rye in soybean affects rotational crops in upstate Missouri

AbstractOverseeding may help farmers establish cover crops (CCs) in a relay intercropping system and avoid labor and time constraints during harvest while providing grazing opportunities for integrated crop–livestock systems. This research evaluated timings (overseeded at R6, R6.5, R7, R8, and post‐harvest) of cereal rye (CR; Secale cereale L.) and ryegrass (RG; Lolium multiflorum L.) CC plantings on soybean [Glycine max (L.) Merr.] yield, CC heights and dry mass in the spring, and the subsequent impact on rotational crop (corn [Zea mays L.] or soybean) yield compared with the absence of a CC (nonseeded control) and drill‐seeded CC treatments following soybean harvest. Soybean light interception (LI) during the overseeding timings differed between years which along with precipitation and temperature affected fall and spring growth of grass CCs. Earlier‐seeded CCs were generally taller and had greater dry mass than post‐harvest seedings, depending on the year. Conventional‐tilled soybean yields and the subsequent no‐till soybean crop following CCs were not affected when CCs were seeded at R6.5 or later. No‐till soybean yields were not affected by overseeded CCs when seeded at R6 or later; however, all CC seedings except post‐harvest overseeded CCs reduced corn yields 16–33 bu acre–1 compared with the nonseeded control. Overseeding is an option for farmers wanting to establish a CC, but risk to the intercropped and rotational crop yield occurs if seeded too early and can depend on the rotational crop.

Response of broadleaf and grass cover crop species to soil residues of glyphosate and aminomethylphosphonic acid (AMPA)

AbstractGlyphosate is the most widely used herbicide in the United States; however, concern is escalating about increasing residues of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) in soil. There is a lack of scientific literature examining the response of cover crops to soil residues of glyphosate or AMPA. The objectives of this study were to evaluate the impact of glyphosate or AMPA residues in silty clay loam soil on emergence, growth, and biomass of cover crops, including cereal rye, crimson clover, field pea, hairy vetch, and winter wheat, as well as their germination in a 0.07% (0.7 g L–1) solution of AMPA or glyphosate. Greenhouse studies were conducted at the University of Nebraska–Lincoln to determine the dose response of broadleaf and grass cover crops to soil-applied glyphosate or AMPA. The results indicated that soil treated with glyphosate or AMPA up to 105 mg ae kg–1 of soil had no effect on the emergence, growth, above-ground biomass, and root biomass of any of the cover crop species tested. To evaluate the impact of AMPA or glyphosate on the seed germination of cover crop species, seeds were soaked in Petri plates filled with a 0.7 g L–1 solution of AMPA or glyphosate. There was no effect of AMPA on seed germination of any of the cover crop species tested. Seed germination of crimson clover and field pea in a 0.7 g L–1 solution of glyphosate was comparable to the nontreated control; however, the germination of cereal rye, hairy vetch, and winter wheat was reduced by 48%, 75%, and 66%, respectively, compared to the nontreated control. The results suggested that glyphosate or AMPA up to 105 mg ae kg–1 in silt clay loam soil is unlikely to cause any negative effect on the evaluated cover crop species.

ARAHAN PENGGUNAAN LAHAN BERDASARKAN KELAS KEMAMPUAN LAHAN DI DAS PANGKAJENE BAGIAN HULU DESA LANNE KECAMATAN TONDONG TALLASA KABUPATEN PANGKEP

Land use must meet the requirements necessary for the land to be productive and not be damaged for an indefinite period of time. Transfer of land use is one of the causes of damage to watersheds (DAS), causing complex physical, economic and social problems both upstream and downstream. Land resources in the upstream watershed (DAS) are easily degraded due to erosion. Therefore, the management of land resources in the upstream watershed has an increasingly important role, especially in efforts to use it in a sustainable manner. This research is descriptive qualitative. The data obtained were based on purposive sampling, for each land use and were analyzed based on the land capability classification criteria. The results showed that the Pangkajene watershed upstream of Lanne Village, Tondong Tallasa District, Pangkep Regency has five land uses, namely Protected Forest with ability class VII, rice fields, gardens and shrubs with ability class VI and settlements with land capability class IV. The suitable land uses in the land capability class are Protection Forest and shrubs. Incorrect land use, namely rice fields, gardens and settlements. Unsuitable land use, namely rice fields and gardens, is directed towards land rehabilitation, while settlements are directed to use conservation techniques in the form of leveling the land on a sloping location and mixed garden settlements with moderate density in the form of fruit plants interspersed with grass cover crops. The process of this activity is carried out by still following the pattern of community activities and the principles of soil and water conservation to increase benefits both economically and ecologically

Utilization of the neighborhood design to evaluate suitable cover crops and their density for Echinochloa colona management.

Summer weed species, including Echinochloa colona, are becoming problematic in the eastern grain region of Australia, but cover crops can be useful to suppress weeds during the summer fallow period. The present study evaluated the growth and seed production of E. colona grown alone or with four and eight cover crop plants per pot (i.e., 80 and 160 plants m-2). Four legume (cowpea, lablab, pigeonpea, and soybean) and two grass (forage sorghum and Japanese millet) cover crops were used. Interference by cover crops reduced the height, the number of leaves and tillers, inflorescence number, seed production, and biomass of this weed than when it was grown alone. Cover crops differed in their ability to suppress the growth and seed production of E. colona. The effect of cover crop density on the studied attributes was non-significant in most cases. Pigeonpea as a cover crop was the least effective in suppressing the growth and seed production of E. colona. In general, leguminous cover crops exhibited less suppression of E. colona than grasses. Forage sorghum was most efficient in reducing the growth of this weed. Forage sorghum and Japanese millet reduced E. colona leaf and tiller numbers per plant by 90 and 87%, respectively. These cover crops reduced E. colona leaf number to only 17 per plant as against 160 per plant recorded without cover crops. Inflorescence number per E. colona plant growing alone was as high as 48. However, it was reduced by 20–92% when this weed was grown with cover crop plants. E. colona’s seed production was significantly suppressed by all the cover crops, except pigeonpea. Biomass of E. colona was suppressed largely by forage sorghum and Japanese millet compared to other cover crops. Among the cover crops, pigeonpea produced the lowest biomass of 11 g pot-1, and the highest biomass (114 g pot-1) was produced by forage sorghum. The study demonstrated the usefulness of cover crops, especially forage sorghum and Japanese millet, to suppress the growth and seed output of E. colona.

On-farm assessment of cover cropping effects on soil C and N pools, enzyme activities, and microbial community structure

AbstractIntroducing cover crops (CC) in annual cropping systems can promote nutrient cycling and improve soil health. However, impacts of CC on soil health indicators vary and depend on the duration of CC, cropping systems, and other environmental conditions. We performed an on-farm assessment of cover cropping impacts on soil health indicators including C and N pools, enzyme activities, and microbial community structure under different no-till maize-based cropping systems (maize (Zea mays L.)–soybean (Glycine max L.) [CS], CS-winter wheat (Triticum aestivum L.) [CSWw], and maize-oats (Avena sativa L.) [CO]). At five farms, fields with different durations of CC were compared to adjacent no CC (NCC) fields. In general, long-term CC enhanced the soil health parameters compared to NCC. Long-term (20-year) winter rye CC had higher water-extractable C and N content, enzyme activities (β-glucosidase (1.2 times greater), urease (5.5 times greater), acid (1.5 times greater) and alkaline (4 times greater) phosphatase, arylsulfatase (0.8 times greater) and fluorescein diacetate (FDA) (0.7 times greater)) and soil bacterial community abundance (1.2 times greater). Short-term (3–6 years) legume and grass CC mixtures increased β-glucosidase (0.9 times), acid (0.7 times) and alkaline (1.5 times) phosphatase, arylsulfatase (3 times), FDA (0.8 times) activities and total phospholipid fatty acid (1.6 times) concentration. However, short-term (3–6 years) winter rye, legume and brassica mixtures did not significantly alter soil microbial community structure. This study showed that implementation of CC for >6 years promoted C, N, S, and P cycling that are beneficial to soil health in maize-based cropping systems.