Influence Of Cover Crops Research Articles

INFLUENCE OF SOIL TREATMENT ON THE NUMBER OF EARTHWORMS AND THE SIZE OF MICROBIAL BIOMASS UNDER THE CONDITIONS OF AGRICULTURAL INTENSIFICATION

Objective. To establish the influence of soil treatment methods on the number of earthworms and microbial biomass in dark-chestnut heavy loam soil with observance of the following crop rotation: soybean – winter wheat – corn; verify the hypothesis of the negative influence of traditional soil treatment technologies on the number of earthworms. Methods. Analytical, field, laboratory, system analysis, statistical. Results. During the studies conducted in 2018–2021 at Askanian State Agricultural Experimental Station of the Institute of Irrigated Agriculture of the NAAS, the positive influence of zero soil treatment technologies on the studied parameters versus with traditional technologies was established. A 2.5-fold increase in the number of earthworms and a 1.1-fold increase in microbial biomass was reported with zero soil treatment technologies. The interaction between soil treatment factors and cover crops in the structure of crop rotation was 23.7 %. Soil treatment technologies had a negligible influence on the size of microbial biomass — at the level of 1.4 %. The significance of the action of cover crops in crop rotation was 10.0 %. The experiment also showed a higher number of earthworms in the soil with zero soil treatment technologies with cover crops and traditional technologies for control, due to better live environment and favourable conditions for reproduction and distribution of the population depending on soil treatment technologies. Changes in the density of the soil layer 0–30 cm were within the measurement error (for zero soil treatment technologies the studied parameter was 1.23 g/cm3, for traditional — 1.24 g/cm3). Compaction of 0–20 cm soil layer with zero and traditional soil treatment technologies was reported. The content of soil organic matter by the years of studies under zero soil treatment technologies increased to 3.0 %, which is 1.2 times higher than with traditional technologies. Conclusion. Under the conditions of stationary field experiment the positive influence of zero soil treatment technologies on early changes of biological properties of soil, which were characterized by increase in number of earthworms and size of microbial biomass, has been established. The positive influence of cover crops on soil quality was determined, which was characterized by signs of biota activation in the 0–30 cm layer and improvement of biological and physical properties of the soil.

Cover crops differentially influenced nitrogen and phosphorus loss in tile drainage and surface runoff from agricultural fields in Ohio, USA

Nitrogen (N) and phosphorus (P) loss from crop production agriculture is transported to adjacent and downstream water bodies, resulting in negative environmental impacts including harmful and nuisance algal blooms. Cover crops are a conservation management practice that replaces bare soil with vegetation outside of the cash crop growing season, purportedly reducing N and P loss by increasing water and nutrient demand in agroecosystems. In this study, we compared nitrate (NO3−-N), total N (TN), dissolved reactive P (DRP), and total P (TP) loads in subsurface (tile) drainage and surface runoff from fields with cover crop management (CC) and fields without cover crop management (NoCC) using continuous monitoring data from 40 agricultural fields located throughout northcentral Ohio, United States (US). We found that average monthly tile NO3−-N and TN loads from CC fields were ~50% less than NoCC fields, while average monthly tile discharge, DRP, and TP loads did not differ between CC and NoCC fields. Cover crops also did not significantly influence average monthly surface metrics. Cover crops reduced monthly totals of tile NO3−-N and TN loads by ~1.0–2.6 kg N ha−1 from January to June (winter and spring), coinciding with critical periods of nutrient loss from agroecosystems in the midwestern US, but increased monthly totals of tile DRP (by 0.4–12.1 g DRP ha−1) and TP (by 1.2–31.6 g TP ha−1) loads during some months. We found similar patterns at the annual time scale whereby CC fields had lesser cumulative annual totals of tile NO3−-N and TN but greater cumulative annual totals of tile DRP and TP. These results show that the influence of cover crops on N loads, but not P, were consistent across temporal scales of examination, demonstrating that cover crops effectively increased N demand and mitigated N losses from agricultural fields. The variable influence of cover crops on P loads underscores the need for greater understanding of the factors and mechanisms that control P loss in systems that include cover crop management. Furthermore, these findings stress the importance of identifying and selecting conservation management practices tailored to the natural resource concern.

How do nitrogen fertilization and cover crop influence soil C-N stocks and subsequent yields of sugarcane?

Sugarcane production for biorenewables demands substantial inputs of nitrogen (N) fertilizer that can lead to environmental consequences, and no clear effect has been reported on soil organic carbon (SOC) and N stocks. The use of a previous legume crops cultivation to add N to soil is a promising strategy to reduce the dependence in synthetic N fertilizer, having an international appeal for sustainable production of bioenergy crops. This study investigates a four-year impact of N fertilization on SOC and N stocks and sugarcane ratoon yields in a sandy and clayey soils, while considering the effects of a legume cover crop cultivated during the renovation period on decreasing N fertilizer requirements. Treatments with N fertilizer rates were arranged in a randomized block design after plant-cane harvest: 60, 120, 180 kg N ha−1 and control (without N) in two paired areas previously managed with Crotalaria spectabilis and bare fallow. Soil samples for SOC and N stocks were quantified at the beginning of the trial, and measured again along with microbiological attributes after four consecutive years, while sugarcane yield was assessed annually. SOC and N stocks were unaffected by N fertilizer rates, whereas the cultivation of cover crop increased soil N storage and microbial biomass carbon. There was limited responsiveness of sugarcane ratoons to additional N supplied by inorganic fertilizer under cover crop, whereas positive responses occurred under bare fallow. Considering the average of four-harvest yields, cover crop increased sugarcane yield by 9 % (5 Mg ha−1) at sandy soil and 15 % (16 Mg ha−1) at clayey soil relative to bare fallow. Cover crop provided an annual N fertilizer replacement of 9 and 15 kg ha−1 in the sandy and clayey soils. The long-lasting historical effect of cover crop in increasing sugarcane yield per area without the need for extra N from fertilizer opens a new possibility to increase the sustainability and alleviate associated greenhouse gas emissions of sugarcane fields by allowing savings in synthetic N fertilizer.

PHOTOSYNTHETIC PERFORMANCE INDICATORS OF VARIEGATED ALFALFA DEPENDING ON THE SOWING METHOD IN THE FOREST STEPPE OF THE MIDDLE VOLGA REGION

Undercrop cultivation of alfalfa is economically justified, since in the year of sowing, cover crops give a full harvest, and also one mowing of alfalfa for hay is carried out, moreover the special preparation of the soil for grasses is not re-quired. In the conditions of the Middle Volga region, the experiment was laid on leached chernozem in 2017 - 2019, where they studied the sowing of variegated alfalfa under the crops of spring wheat, barley, oats, harvested for grain and an-nual grasses - for green fodder, and studied the options for coverless sowing, where the weeds were mowed twice and the herbicide Pivot was applied at the beginning of alfalfa branching. The total biological yield is determined by the leaf area and its photosynthetic activity. Therefore, the purpose of the research is to determine the indicators of alfalfa photosynthetic activity for an objective as-sessment of the influence of cover crops on their forage productivity. It has been established that a more intensive increase in the assimilation surface of alfalfa in the first year of life to 31.6 and 30.6 thousand m2 /ha occurs on coverless sowing with the application of the Pivot herbicide and two-fold mowing of weeds. The dry matter yield was 2.1 and 2.0 t/ha, respectively. A decrease in the illumination of alfalfa plants sown under crops, where the leaf area did not exceed 13.0...15.3 thousand ? m2 / ha, slowed down the photosynthesis processes. Moreover, a more intensive growth of its photosynthetic organs was noted under the crop of barley, the cereal-legume mixture reduced the leaf area by 0.5 thousand m2 /ha, the pho-tosynthetic potential was 898...1051 thousand m2 day/ha.

Cover crop influence on soil water dynamics for a corn–soybean rotation

AbstractCrop production is reduced by insufficient and/or excess soil water, which can significantly decrease plant growth and development. Therefore, conservation management practices such as cover crops (CCs) are used to optimize soil water dynamics, since CCs can conserve soil water. The objective of this study was to determine the effects of CCs on soil water dynamics on a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation at three soil depths over 3 yr. The study was conducted at the Chariton County Cover Crop Soil Health Research and Demonstration Farm (CCSH) in Missouri. Initial CC establishment occurred in 2012. Volumetric soil water content (VWC) was monitored at 15‐min intervals with calibrated Waterscout SM100 soil moisture sensors (Spectrum Technologies) at three depths (10, 20, and 30 cm) in 2016, 2017, and 2018. Cover crop soils maintained numerically higher VWC values compared with no CC (NCC) at both 10‐ and 20‐cm depths throughout the study period where the differences were significant in some weeks. The subsurface soil water recharge was greater in CC soils at both 10‐ and 20‐cm depths compared with NCC in March 2017. The results imply that CC soils have maintained higher VWC levels during vegetative period of the CC growth where the differences were significant in some weeks compared with NCC at all three soil depths. These findings can be used to promote CC adoption for better soil water storage and develop CC management plans for corn–soybean rotations on claypan soils.

Use of cover crops in the southern Amazon region: What is the impact on soil physical quality?

Introducing cover crops during the rotation system and off-season can provide numerous benefits to the agricultural system, such as increased carbon stock and improved soil aeration. However, in the southern Amazon region, owing to the hot and humid climate, the cover crops used in agricultural production systems may not have the same beneficial effects in the Cerrado region. This makes it necessary to introduce and study new species of cover crops that have the potential to improve soil quality. The objective of this study was to compare, over time, the dry matter production of eight cover crops, and the effects of their cultivation on the physical attributes of the soil in the southern Amazon region. The experiment was conducted in a randomized complete block design with analyzes carried out over the 3 years of the experiment, in three replicates. The treatments were composed of eight cover crops: crotalaria (Crotalaria spectabilis), pigeon pea (Cajanus cajan), velvet-bean (Mucuna aterrima), buckwheat (Fagopyrum esculentum), ruziziensis grass (Urochloa ruziziensis), brizantha grass (Urochloa brizantha), pearl millet (Pennisetum glaucum), and finger millet (Eleusine coracana), and three evaluation years (2014, 2015, and 2016). The cover crops used in the experiment were selected based on their adaptation to the growing conditions and because they have characteristics of agricultural interest. In addition, cover crops chosen can be used in soybean-maize rotation systems, soybean-maize succession systems, as well as in agriculture-livestock integration systems through integrated cultivation systems. Using undisturbed soil samples, were analyzed the physical variables: porosity, mechanical resistance to root penetration and water retention. Pore size distribution was calculated using the first derivative of the equation of van Genuchten and S index was determined by the angle of inclination of the soil water retention curve inflection point. The results show that leguminous and grassy cover crops act differently under physical soil attributes over time. The results indicated that the cultivation of grasses, such as P. glaucum, increased the values of macroporosity (0.18 m3 m−3) in the 0.00–0.10 m layer at the end of the third year of cultivation, consequently, reduced the value of soil density (up to 1.14 Mg m−3) and mechanical resistance to root penetration (up to 1.77 MPa). The largest accumulation of dry matter was obtained with the cultivation of U. brizantha, which consequently proved to be the best cultivation option in the off-season in the southern Amazon region. The study provides a better understanding of the influence of cover crops on the physical attributes of the soil, which will contribute to making the correct recommendation of cover crops that can improve the physical properties of the soil in agricultural frontier regions in the southern Amazon rainforest.

Influence of Cover Crop, Tillage, and Crop Rotation Management on Soil Nutrients

Cover cropping, tillage and crop rotation management can influence soil nutrient availability and crop yield through changes in soil physical, chemical and biological processes. The objective of this study was to evaluate the influence of three years of cover crop, tillage, and crop rotation on selected soil nutrients. Twenty-four plots each of corn (Zea mays) and soybean (Glycine max) were established on a 4.05 ha field and arranged in a three-factor factorial design. The three factors (treatments) were two methods of tillage (no-tillage (NT) vs. moldboard plow [conventional] tillage (CT)), two types of cover crop (no cover crop (NC) vs. cover crop (CC)) and four typess of rotation (continuous corn, continuous soybean, corn/soybean and soybean/corn). Soil samples were taken each year at four different depths in each plot; 0–10 cm, 10–20 cm, 20–40 cm and 40–60 cm, and analyzed for soil nutrients: calcium (Ca), magnesium (Mg), nitrogen (NO3 and NH4), potassium (K), phosphorus (P), sulfur (S), sodium (Na), iron (Fe), manganese (Mn) and copper (Cu). The results in the first year showed that CT increased NO3-N availability by 40% compared with NT. In the second year, NH4-N was 8% lower under CC compared with NC management. In the third year, P was 12% greater under CC management compared with NC management. Thus, CC can enhance crop production systems by increasing P availability and scavenging excess NH4-N from the soil, but longer-term studies are needed to evaluate long-term effects.

The Combined Influence of Cover Crops and Manure on Maize and Soybean Yield in a Kentucky Silt Loam Soil

Management that degrades soil can be one of the main causes of low agricultural productivity and environmental problems in many agricultural regions. There is renewed interest in soil conservation practices to promote sustainable agriculture by improving soil quality and productivity. In this study, the short-term on-farm benefits of cover crops and manure on crop yield and biomass were examined during two consecutive growing seasons. The experiment was conducted at a small-producer farm in Logan County, Kentucky, USA. Soybean (Glycine max L.) and maize (Zea mays L.) were used as summer annual rotation crops in no-tilled soils. A cover crop mix of cereal rye (Secale cereale L.), Austrian winter pea (Pisum sativum L.), and crimson clover (Trifolium incarnatum L.) was planted after the main crop was harvested each year. Aboveground biomass of the soybean and maize were assessed, and yield was estimated from hand-harvested plants. In the first year of the study (2016), there were apparent but not significant beneficial effects of animal manure and cover crops on soybean yield, but not on biomass. The biomass and maize grain yield in the second year (2017) were detectable, significant, and increased as a result of the cover crops and manure application (p < 0.05). While beneficial effects of combining cover crops and manure may not be obvious in the first year of a rotation, they can be apparent in subsequent years. However, longer-term observation and measurement are necessary to better quantify the relationship between sustainable conservation practices and productivity.

Does winter oilseed rape as a winter cover crop influence potato late blight development in an organic crop rotation?

ABSTRACTIn this study, the effects of a winter cover crop (CC) and its combination with composted cattle manure (CC-M) on the development of potato late blight (Phytophthora infestans) and crop yield were investigated and compared with a system with no cover crop (NC). In the CC and CC-M systems, winter oilseed rape (Brassica napus L) was used as the winter cover crop before potatoes. The hypothesis that the cover crop could be used as a possible control strategy against late blight in organic potato cultivation was not confirmed. Although the progression of foliar late blight damage in CC treatment was significantly slower in the early stages of disease development relative to NC, CC did not significantly reduce late blight at the later stages, or over the full season, and it did not increase tuber yield. Adding cattle manure to the CC treatment favoured late blight development and the damage was significantly more severe than in the other systems and tuber yield was nominally lower (though not significantly). The late blight pressure differed between treatments, with early disease development significantly slower on CC plots compared to CC-M in both growing seasons, but still not different to that in the plants grown in the NC system. Based on the results, in regions where oospores are a primary infection source, making P. infestans a soilborne pathogen, the use of cover crops may provide a sustainable strategy for reducing late blight damage in an organic system, but further investigation is needed.

Tillage and cover crop influence on weed pressure and Fusarium infection in spring cereals

Several studies have reported positive effect of cover crop on topsoil physical properties as well as weed suppression, but few have quantified its effect on Fusarium head blight prevention. This study explored the effect of white mustard (Sinapis alba L.) and white clover (Trifolium repens L.) as cover crops on weed pressure and Fusarium infestation in spring wheat and spring barley grain under different tillage systems.Five tillage practices were investigated in a loam soil in long term tillage experiment in Central Lithuania in Dotnuva: deep ploughing (22–24 cm), shallow ploughing (16–18 cm), shallow harrowing (8–10 cm), deep harrowing (14–16 cm) and direct drilling, with and without cover crop. Cover crops were sown using fertilizer spreader: white mustard seed were spread before harvest of the spring wheat and spring barley in 2013 and 2014, respectively and white clover – at the beginning of vegetation of winter oilseed rape in early spring, in 2017. Cover crops effect on Fusarium fungi was evaluated in spring cereals grown after the cover crop: in spring barley in 2014 and in spring wheat in 2018.Both cover crops resulted in lower weed pressure for a post - harvest period under different tillage practises. White mustard suppressed weed air-dry mass up to 90 and white clover up to 99 percent. White mustard has influenced the decrease of Fusarium graminearum contamination in spring barley grain as well as white clover reduced F. culmorum infestation level in spring wheat grain. Our results suggest that white mustard and white clover as cover crops might be an option for integrated pest management in order to supplement weed control strategy and Fusarium head blight prevention under sustainable tillage practises.

Soil Biological Response to Integration of Cover Crops and Nitrogen Rates in a Conservation Tillage Corn Production System

Core Ideas Use of N‐fertilizers decreased AMF populations and P, Ca, and Mg concentrations. Conservation tillage and cover crops increased C, N, and S cycling enzymes. Grass and brassica cover crops increased microbial populations compared to legumes. Agricultural production in the US Mid‐South has relied on frequent tillage and synthetic fertilizers decreasing soil health and system sustainability. Conservation tillage and cover crops can fill a vital role in reducing soil erosion while improving ecosystem functions. Seven cover crop blocks, including four legumes (berseem clover [Trifolium alexandrinum], crimson clover [Trifolium incarnatum L.], winter pea [Pisium sativum L.], and hairy vetch [Vicia villosa Roth], three grass & brassica (cereal rye [Secale cereale], forage radish [Raphanus sativus var. longipinnatus], and a cereal rye–forage radish mix), and one fallow control were established in northeast Louisiana to examine the influence of cover crop and urea fertilizer application rates (0, 235, 268, 302 kg N ha−1) on corn production and soil health under conservation tillage. Soil health indicators were measured each year following corn harvest and cover crop termination. The combination of cover crops and conservation tillage increased C and N enzyme activity over the 2 yr while arylsulfatase increased in the spring following cover crop termination only. Relative abundance of saprophytic fungi tended to be higher in legume plots compared to grass & brassica treatments. Overall, the application of N fertilizer at rates of 235 kg N ha−1 or higher decreased populations of AMF and concentrations of P, K, Ca, and Mg, but increased populations of Gram‐positive bacteria. The use of grass & brassica cover crops promoted K, S, Ca, and Mg availability, and supported greater abundance of total FAMEs and all FAME biomarkers except for saprophytic fungi.

Cover Crop Influence on Soil Enzymes and Selected Chemical Parameters for a Claypan Corn–Soybean Rotation

Cover crops (CC) improve soil quality, including soil microbial enzymatic activities and soil chemical parameters. Scientific studies conducted in research centers have shown positive effects of CC on soil enzymatic activities; however, studies conducted in farmer fields are lacking in the literature. The objective of this study was to quantify CC effects on soil microbial enzymatic activities (β-glucosidase, β-glucosaminidase, fluorescein diacetate hydrolase, and dehydrogenase) under a corn (Zea mays L.)–soybean (Glycine max (L.) Merr.) rotation. The study was conducted in 2016 and 2018 in Chariton County, Missouri, where CC were first established in 2012. All tested soil enzyme levels were significantly different between 2016 and 2018, irrespective of CC and no cover crop (NCC) treatments. In CC treatment, β-glucosaminidase activity was significantly greater at 0–10 cm depth in 2016 and at 10–20 and 20–30 cm in 2018. In contrast, dehydrogenase activity was significantly greater in NCC in 2018. Soil pH and organic matter (OM) content were found to be significantly greater in CC. Overall, CC have mixed effects on soil enzyme activities and positive effects on soil OM compared to NCC. This study highlights the short-term influence of CC and illustrates the high spatial and temporal variability of soil enzymes under farmer-managed fields.

Soil health indicator responses on Missouri claypan soils affected by landscape position, depth, and management practices

Improved soil productivity will be vital to meet expected food and fiber demands of growing populations. Concepts of soil health assessments focus on specific soil properties and determination of a soil9s ability to maintain a range of ecological functions in its appropriate ecosystem, supporting long-term sustainability. Objectives of the investigation were to determine the influence of cover crop, soil depth, and landscape under varied management practices on biological soil health indictors. Four watersheds within the Chariton County Cover Crop Soil Health Farm, Missouri, United States, with Armstrong loam (fine, smectitic, mesic Aquertic Hapludalfs, 5% to 9% slopes eroded) were used for the study. Two watersheds were managed with cover crops, rotational planting, and no-till applications. Initial cover crop planting occurred during the fall of 2012. Two control watersheds received no cover crop management. It is important to note drought conditions persisted over the 2012 and 2013 growing seasons. Soils were sampled in 2012 and 2014 by landscape and depth (0 to 10, 10 to 20, and 20 to 30 cm) from the watersheds. Analyses included soil enzymatic activity, soil microbial diversity, and soil nutrients. Enzyme activities and nutrient levels significantly decreased with soil depth. For example, β-Glucosidase 0 to 10 cm depth values ranged from approximately 85 to 100 μg of para-nitrophenol (PNP) per gram oven dry soil (gds⁻¹), with 20 to 30 cm depth values ranging from approximately 35 to 40 μg PNP gds⁻¹. Nutrient levels, enzyme activities, and water stable aggregates displayed various levels of significance across landscape positions (<i>p</i> &lt; 0.01 and <i>p</i> &lt; 0.05). Carbon (C) and select enzyme indicator parameter measurements significantly (<i>p</i> &lt; 0.01 and <i>p</i> &lt; 0.10) differed between sampling events. We expected to detect significant relationships between soil biological activities and land management practices to identify practices that lead to improving soil health. However, identifying cover crop effect between watersheds proved challenging due to poor stand establishment and the duration of the monitoring period, emphasizing the importance of extended monitoring to determine the effects associated with long-term management conditions and health assessment practices.

Uticaj jarih useva gajenih nakon ozimih međuuseva na stanje sabijenosti zemljišta

The aim of the paper was to determine the influence of cover crops (CC) and cultivated crops in the subsequent sowing period (maize, soybean and sudan grass) on the physical properties of the soil, and above all on the soil compaction.Research was carried out at the Rimski Šančevi experimental station. Type of soil - chernozem. The winter CC consisted of the combined intercrops: winter pea (Pisum sativum ssp. Arvense L.) + triticale ((×Triticosecale Wittm. ex A. Camus) (PT) and single-species CC winter pea (P)and control (without CC). Plowing of CC and control plots was carried out in the last week of May 2018, and the sowing of maize, soybean and sudan grass was carried out in early June. Soil compaction was analyzed on the basis of collected data on the resistance of cone penetration into the soil and the immediate moisture content of the soil. The penetration resistance of the cone into the soil was determined using an electric penetrologger Eijkelkamp Penetrologger. Measurement of the resistance was carried out to a depth of 80 cm and expressed in MPa. Based on the conducted research, the smallest percentage content of soil moisture at depths of up to 20 cm was determined for maize varieties (PT) of 10.5% vol.and the highest on the control plot (without CC) (25.7% vol.), as a consequence of the absence of the CC, but also the dense structure of Sudan grass and reduced evaporation from the production area. The lowest Cone index (CI) was measured on a plot also with sudan grass, on the soil preceded by the cultivation of the winter pea as cover crop ( 2,3), while the highest index (3,6) was measured in the soybean crop on variants (PT). The specific resistance to penetration of the cone was varied both on varieties of inter CC (PT), single CC (P) and control, as well as in different cultivated species in the subsequent sowing period. The highest value of the specific resistance in the depth 0-20 cm was found in soybean (PT) 2.76 MPa, and also increased compation in the same crop in the layer (20-40 cm). On the basis of the obtained values it can be concluded that maize least affects soil compaction, unlike soybean, while in relation to the cover crops it is determined that the winter pea has the least impact on soil compaction.

Winter cover crops reduce nitrate loss in an agricultural watershed in the central U.S.

Agricultural land use in the Midwestern U.S. is the major source of nitrogen (N) causing recurring hypoxia in the northern Gulf of Mexico. Despite efforts to reduce losses, N export from tile-drained, agricultural watersheds throughout the Corn Belt persists. The use of effective agricultural conservation practices can reduce N loss from fields, yet little is known about how field-scale implementation will translate into watershed-scale reductions in N export. In this study, we used a sampling approach with high spatial and temporal resolution to quantify changes in tile drain load and watershed export of nitrate (NO3−-N) after planting cover crops on >60% of croppable acres in a small, agricultural watershed. We found that median NO3−-N losses from tiles draining fields with cover crops were 69–90% lower than tiles draining fields without cover crops during winter/spring. Measured instantaneous flow was the major driver of NO3−-N losses from tile drains, though results suggest that this relationship differed between tiles with and without cover crops in spring. The signature of cover crops at the field-scale was evident in watershed NO3−-N export, particularly during times of elevated flows; median daily NO3−-N exported in elevated flows was 18–22% lower during years with watershed-scale planting of cover crops compared to years without. Nevertheless, changes in watershed NO3−-N export were smaller than the observed reductions in tile drain loads. Results indicate that tile drain reductions directly reflected the influence of cover crops at the field-scale while watershed export integrated both past and present management, ultimately complicating attempts to distinguish the effect of conservation efforts at larger spatial scales.

Influence of Cover Crop and Tillage Systems on Optimal Nitrogen Rate for Tennessee Cotton Considering Risk

Upland cotton fields have minimal amounts of crop residue after harvest to cover the soil surface, which exposes the soil and increases the risk of soil erosion. This is especially challenging in the Mid-South U.S. where cotton is commonly grown on sandy or silty soils that are naturally prone to soil erosion. Winter cover crops and no-till planting are two practices that can mitigate soil erosion by increasing soil surface biomass. However, there is uncertainty on how these practices can impact producers’ profits and risk. We determine the influence of four winter cover crops and two tillage systems on the optimal nitrogen rates, cotton yields, and net returns for risk-neutral to risk-averse cotton producers. Data came from a long-term nitrogen (N), tillage, and cover crop experiment in Tennessee. A flexible moment model was used to estimate the impact of risk on the decision to plant cover crops and tillage system. Planting cover crops on till planted cotton decreased optimal N fertilizer rate as well as optimal yields. However, the impact of cover crops on optimal N rate, yields, net returns for no-till planting depends on the cover crop species. A risk-neutral producer would select a till and no cover crop system, but as risk aversion increases, no-till planting with no cover crop system was optimal. Results improve the understanding into the profitability and risk of using cover crops and no-till, which will assist producers in making optimal production systems.

In situ infiltration as influenced by cover crop and tillage management

Water is usually the most limiting factor in agricultural grain crop production. Various agricultural management practices, such as tillage and use of cover crops, have the potential to influence water infiltration into soil. This study was conducted on a Waldron silt loam (fine, smectitic, calcareous, mesic Aeric Fluvaquents) soil to evaluate the influence of cover crop and tillage management on in situ infiltration. The field site included three replicate blocks in a randomized complete block design with each plot measuring 21.3 m (69.9 ft) length and 12.2 m (40 ft) width. The two treatment factors included cover crop at two levels (cereal rye [Secale cereale] cover crop [CC] versus no cover crop [NC]) and tillage at two levels (moldboard plow tillage [Till] versus no-tillage [NT]). Continuous corn (Zea mays L.) was grown. Infiltration rates were measured in all the treatments using a Mariotte system with single-ring infiltrometers during the 2014 and 2015 growing seasons. Water infiltration parameters were estimated using the Parlange and Green-Ampt infiltration equations. Parlange and Green-Ampt models appeared to fit measured data well with coefficient of variation ranging from 0.92 to 0.99. In 2014, the saturated hydraulic conductivity (KS) parameter value determined from the Parlange model was 30.4 mm h−1 (1.2 in hr−1) for NT, about 42% greater than Till. The KS parameter value determined from the Green-Ampt model was 25.9 mm h−1 (1 in hr−1) for NT, about 54% greater than Till. In 2015, the sorptivity (S) parameter value determined from the Parlange model was 38.6 mm h−0.5 (1.5 in hr−0.5) for CC, about 82% greater than NC. The S parameter value determined from the Green-Ampt model was 34 mm h−0.5 (1.3 in hr−0.5) for CC, about 90% greater than NC. Cover crop management can increase water infiltration, which can improve soil quality and enhance the sustainability of crop production systems.

Cover crop differentially affects arthropods, but not diseases, occurring on grape leaves in vineyards

Background and Aims Cover crop has become a common management practice in viticulture. It improves the structure and protects the soil, enhances natural enemy populations and also reduces the vigour of the vine. Here, we investigated the effect of cover crop in vineyards on grapevine diseases and arthropods present on leaves. Methods and Results We measured the presence of the pathogens Plasmopara viticola, Uncinula necator and Guignardia bidwellii and monitored six common beneficial/pest arthropods: Panonychus ulmi, Orthotydeus lambi, Typhlodromus pyri, Scaphoideus titanus and Phalangium opilio in vineyards with cover crop or bare soil in 2014 and 2015. The density of the two pests P. ulmi and S. titanus and the beneficial mite O. lambi was lower in cover crop, while the density of the beneficial predatory mite T. pyri was higher in cover crop. We found no influence of cover crop on P. opilio and on the presence of grapevine diseases. Conclusions These findings point to a simple way to increase the population of beneficial arthropods and reduce pest arthropods, which could help integrated pest management programs. Significance of the Study To our knowledge, this is the first study monitoring the cover crop influence on both diseases and arthropods. It would help growers to optimise space management between rows to enhance their natural enemy populations while reducing pesticide application.

Influence of cover crops on arthropods, free-living nematodes, and yield in a succeeding no-till soybean crop

Production practices that incorporate fall-planted cover crops into no-till agronomic crop rotations have become increasingly popular across the Northeastern United States for weed suppression and enhancing environmental stewardship. Field experiments were conducted in 2011 and 2012 to investigate effects of rotating cereal (barley, Hordeum vulgare), legume (Austrian winter pea, Pisum sativum subsp. arvense), cereal/legume cover crop mixture, and a fallow (bare-ground) control on above- and belowground fauna in a succeeding soybean crop. Free-living nematodes and soybean foliar arthropods were sampled through time to determine effects of cover crops on soil food web structure and complexity and herbivorous and beneficial arthropods, respectively. Our hypotheses were that organic matter from cover crop biomass would provide energy and nutrients to the soil food web and that increased habitat complexity from cover crop residue would provide habitat for more predatory arthropods aboveground. In general, cover crops in this no-till system had a stronger influence on the below- than aboveground fauna. There was no consistent, positive effect of cover crops on beneficial foliar arthropods or on soybean yield. Cover crops increased the soil food web structure and complexity as determined by nematode community indices. Specific effects of different cover crop types on the free-living nematode community varied within the growing season and between study years. Probable causes for differences encountered among cover crop treatments and years are discussed.

Cover crops have neutral effects on predator communities and biological control services in annual cellulosic bioenergy cropping systems

Maize stover is beginning to be used as a cellulosic biofuel feedstock in the Midwestern United States; however, there are concerns that stover removal could result in increased soil erosion and loss of soil organic matter. Use of a winter cover crop following maize harvest has the potential to mitigate these impacts and may have additional benefits by providing continuous living cover in annual crop habitats leading to changes in insect predator communities and increased biocontrol services. However, cover crops may also be harvested in cellulosic biofuel systems, adding a disturbance event that may negatively affect biocontrol. We contrasted insect predator communities and their impacts in four potential bioenergy cropping systems in Michigan and Wisconsin (USA) during the 2013 and 2014 growing seasons. Two annual maize systems were harvested for grain and stover; one maize system included a cereal rye/Austrian winter pea cover crop. Two perennial systems, switchgrass and a mixed prairie grasses and forbs, were harvested in the fall for biomass. Predatory insect abundance and diversity were lower in both annual cropping systems than in the perennial cropping systems and the inclusion of the cover crop did not significantly alter these responses. Similarly, removal of sentinel insect egg prey was also lower in the annual versus perennial cropping systems, with no significant influence of cover crop. We also explored the potential for cover crops to harbor prey populations in the spring that might encourage oviposition by mobile predators and potentially lead to local population sources or sinks of predators depending on the timing and effect of cover crop harvest. We found that existing predator communities in the cover crop treatments effectively suppressed aphid population growth, limiting their attractiveness to mobile predators. While we found no significant positive or negative impacts of this cover crop system on biocontrol services, bioenergy cover cropping systems could be managed to increase multiple ecosystem services by altering cover crop identity, or timing of planting and harvest.