Use Of Cover Crops Research Articles

A comparative study of fifteen cover crop species for orchard soil management: water uptake, root density traits and soil aggregate stability

Increasing the use of cover crops (CCs) is a necessity in sustainable viticulture, although it might clash with possible excessive competition towards vines. Especially in a climate-change scenario, the latter feature should be minimized while maintaining ecosystem services. Aimed at identifying CCs for vineyard floor management, the trial characterized several species according to their evapotranspiration (ET) rates, root growth patterns, and soil aggregate stability potential. The study was performed in 2020 in Piacenza (Northern Italy) on 15 CC species grown in pots kept outdoor and classified as grasses (GR), legumes (LE) and creeping (CR). Together with bare soil (control), they were arranged in a complete randomized block design. CCs ET was assessed through a gravimetric method, starting before mowing and then repeated 2, 8, 17 and 25 days thereafter. Above-ground dry biomass (ADW), root length density (RLD), root dry weight (RDW) and root diameter class length (DCL) were measured, and mean weight diameter (MWD) was calculated within 0–20 cm depth. Before mowing, ET was the highest in LE (18.6 mm day−1) and the lowest in CR (8.1 mm day−1) the latter being even lower than the control (8.5 mm day−1). The high ET rates shown by LE were mainly related to very fast development after sowing, rather than to a higher transpiration per unit of leaf area. After mowing, the 15 species’ ET reduction (%) plotted vs leaf area index (LAI, m2 m−2) yielded a very close fit (R2 = 0.94), suggesting that (i) a linear decrease in water use is expected anytime starting with an initial LAI of 5–6, (ii) a saturation effect seems to be reached beyond this limit. Selection of cover crop species to be used in the vineyard was mainly based on diurnal and seasonal water use rates as well as dynamic and extent of root growth patterns. Among GR, Festuca ovina stood out as the one with the lowest ET due to its “dwarfing” characteristics, making it suitable for a permanent inter-row covering. CR species confirmed their potential for under-vine grassing, assuring rapid soil coverage, lowest ET rates, and shallow root colonization.

Benefits, barriers, and use of cover crops in the western United States: Regional survey results

Cover crops provide known benefits to water, air, and soil quality. The western United States is a large cropping region where data on cover crop use are lacking. In this study, we draw on data from a 2020 survey of western farmers from 13 states and territories to broaden the understanding of current cover crop use and the factors that influence cover crop adoption. We examine cover crop use through farmer and farm characteristics, social networks and information access, and psychological measures of attitudes toward cover crops. Based on the results of the 894 survey responses, we find most respondents use or have used cover crops and recognize their many benefits. The highest ranked benefits of cover crops, according to cover crop users, are soil health benefits and reducing soil erosion. The biggest perceived barriers to cover crops, according to cover crop users and nonusers, are costs and knowledge. The greatest predictor of cover crop use in the western United States is larger farm size; however, as income increases, the odds of cover crop use decreases. Farmers who access agriculture-related information on a regular basis and western farmers who perceive more benefits than barriers to cover crops are more likely to use cover crops. This study informs future research, outreach, and policy through insight into motivations and barriers to cover crop use and factors that influence adoption for farmers in the West.

Scaling up agricultural conservation: Predictors of cover crop use across time and space in the US upper Midwest

Scaling up cover crop use will increase crop diversity on agricultural lands and help achieve sustainable production and environmental wellbeing. To increase the total acreage planted to cover crops, more farmers need to use cover crops on a larger proportion of their farms (extent) and for a longer time (longevity), suggesting the importance of spatial and temporal scales of adoption. The adoption literature lacks attention to the spatial and temporal precision of practice measures and misses opportunities to identify consistent or diverse mechanisms for scaling up conservation practices. To fill this gap, we used data from 1,724 corn (<i>Zea mays</i> L.) and soybean (<i>Glycine max</i> [L.] Merr.) farms in Illinois, Indiana, Michigan, and Ohio to study three measures of cover crop usage: the use of cover crops in a single year on a specific field, the percentage of acres planted to cover crops on a farm in a single-year, and years of cover crop use. Our models included key biophysical, operational, policy, social, and psychological factors. We hypothesize that predictors of cover crop adoption and intensity and longevity of use differ. Our results revealed five factors that performed consistently across measures (perceived benefits of cover crops, knowledge, profitability goals, no-till, and rotational diversity), while the effects of the other seven factors varied, including sustainability goals that were only associated with the longevity of use. Policy programs that aim at increasing cover crop use should consider which aspect of scaling-up is being targeted, then focus on corresponding factors that can better tailor policy and education programs to farmer motivations and decision-making contexts.

Economic trade-offs: analysis of hairy vetch (Vicia villosa) cover crop use in organic tomato (Solanum lycopersicumL.) high tunnel systems across multiple regions

AbstractHigh-tunnel (HT) systems have been shown to effectively improve yields, fruit quality and profitability. In order to maximize returns on investment, HTs are frequently planted successively with both winter and summer cash crops and may include &gt;2 crop cycles per year in some climates. The intense cultivation strategies used in HT systems necessitate increased tillage and nutrient demands posing challenges for soil health, environmental quality and long-term economic sustainability, particularly among organic growers. Seasonal rotations that incorporate fertility-building cover crops, such as legumes and other green manures, have the potential to build soil organic matter, improve crop yield and reduce applications of animal manure and/or compost. The economic impact of cover crop use in HT production systems poses important implications for organic growers. In this study, we present three partial budget analyses to quantify the economic benefits from a leguminous winter cover crop–tomato cash crop rotation in HTs across three regions. Data used in the economic analysis come from multi-year organic HT field trials in Kansas (2016–2019), Kentucky (2016–2019) and Minnesota (2016–2020). Direct financial benefits from hairy vetch (Vicia villosa) cover crop N credits were observed but not sufficient to offset the direct and indirect costs of the cover crop practice. A winter cover crop used in organic HT vegetable systems results in negative financial benefits to producers even with conservation incentive payments. These results highlight challenges for organic growers who are required under the USDA National Organic Program to incorporate soil building practices as part of their rotation schedule. The findings will also be of interest to policy makers as they refine cost-share offerings and programming to incentivize cover crop adoption as a conservation strategy.

Influence of gypsum and cover crop on greenhouse gas emissions in soybean cropping systems

Agriculture has the opportunity to mitigate anthropogenic contributions to global change by increasing soil sequestration of greenhouse gases (GHG) and by reducing efflux through management. Common agricultural management practices include crop rotation and use of cover crops. Interest in the use of gypsum in agricultural systems has also increased in recent years. However, little is known regarding how combining gypsum with other management practices impact GHG emissions in soybean (<i>Glycine max</i> [L.] Merr.)-based cropping systems. A study was implemented at three locations (i.e., east-central Indiana, northwest Ohio, and east-central Alabama) to evaluate the influence of gypsum and cover cropping within a continuous soybean and a corn (<i>Zea mays</i> L.)–soybean rotation on crop yield and soil properties. Within this study, carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄) were also monitored periodically following soybean seeding through harvest from 2012 to 2016. The combined gas data were then used to calculate a global warming potential (GWP). Overall, few differences in GHG emissions were observed across sites and years, and no consistent patterns were noted, likely due to large variabilities in gas efflux measurements and limited influence of treatments on trace gases. However, treatment differences were observed for one or more GHG within specific years and at specific sites. Comparison across sites revealed the warmer/wetter climate in Alabama resulted in greater CO₂ efflux, while climate and soil factors at the northern sites led to greater N₂O efflux. At all locations, CH₄ emissions were generally low and sites tended to be small net sinks. Given that GHG emissions drive GWP, it also showed few treatment responses and no consistent patterns. It can be concluded from this study that contributions of gypsum and cover crop to GHG emissions from soil in soybean cropping systems will likely have little influence on contributions to global climate change.

Using three consecutive years of farmer survey data to identify prevailing conservation practices in four Midwestern US states

AbstractGranular temporal and spatial scale observations of conservation practices are essential for identifying changes in the production systems that improve soil health and water quality and inform long-term agricultural research and adaptive policy development. In this study, we demonstrate an innovative use of farmer practice survey data and what can be uniquely known from a detailed survey that targets specific farm groups with a regional focus over multiple consecutive years. Using three years of survey data (n= 3914 respondents), we describe prevailing crop rotation, tillage, and cover crop practice use in four Midwestern US states. Like national metrics, the results confirm dominant practices across the landscape, including corn-soybean rotation, little use of continuous no-till, and the limited use of cover crops. Our detailed regional survey further reveals differences by state for no-till and cover crop adoption rates that were not captured in federal datasets. For example, 66% of sampled acreage in the Midwest has corn and soybean rotation, with Illinois having the highest rate (72%) and Michigan the lowest (41%). In 2018, 20% of the corn acreage and 38% of the soybean acreage were in no-till, and 13% of the corn acres and 9% of the soybean acres were planted with a cover crop. Cover crop adoption rates fluctuate from year to year. Results demonstrate the value of a farmer survey at state scales over multiple years in complementing federal statistics and monitoring state and yearly differences in practice adoption. Agricultural policies and industry heavily depend on accurate and timely information that reflects spatial and temporal dynamics. We recommend building an agricultural information exchange and workforce that integrates diverse data sources with complementary strengths to provide a greater understanding of agricultural management practices that provide baseline data for prevailing practices.

The Impact of Conservative Soil Maintenance Practices in Vineyards on Soil Microbial Diversity and on the Biodiversity of Useful and Harmful Entomofauna

In the context of actual climatic changes, which led to an increase of soil hydric stress, new agrotechnical solutions were experimented to ensure a moisture preservation in soil and the conservation of soil microbial activity. These included the use of mulching systems and the cover crops, in order to replace the use of the classical black furrow system. In this respect, the aim of our study was to evaluate the influence of the use of soil mulching systems and of the cover crops in vineyards on the microbial biodiversity of the soil and on the biodiversity of the useful and harmful entomofauna, in comparison with the classical maintenance system, represented by black furrow. The researches were performed during two particularly dry years in two experimental plots located in Valea Cǎlugǎrescǎ viticultural center. In one of them were experimented, as soil maintenance systems, the total straw mulching and the partial mulching (interval between rows) with marc compost, in the other the artificial grassing of the interval between rows with ornamental clover Nano and with honey plants represented by Melilotus officinalis. The experimental data have shown the positive effect of mulching systems on soil microbial activity, highlighted by an increase of soil microbial load and of its diversity (represented by bacteria, fungi, algae and protozoa), especially in case of mulching with marc compost (15.94 million microorganisms/g of soil, as compared with 5.9 million in case of black furrow system). Also, the ratio between fungi and bacteria was higher in case of partial mulching, this aspect being a favorable factor for soil biological activity. The use of cover crops indicated a positive effect in the increasing of useful entomofauna, belonging to the orders Ortoptera, Coleoptera and Arahnidae (especially in case of the artificial grassing).

Understanding farmers’ perception of extreme weather events and adaptive measures

Extreme weather events have cost lives and financial losses across the United States. Moreover, they are expected to increase in frequency, and this will exacerbate their impact on vulnerable sectors such as agriculture. But how farmers could adapt to extreme weather events by adopting different conservation practices has received slight attention in the literature. This study examines how farmers' perceptions of drought and flooding influence their decisions to implement conservation practices in their conventional crop fields. Out of the 350 farmer responses we received, fewer than half indicated a likelihood to adopt no-tillage/reduced tillage (43%), cover crops (40%), crop diversification (37%), and integrated crop-livestock grazing (29%). Using this data and a multivariate probit modeling framework, we show that farmers’ decisions can be partly explained by their perception of drought but not by their perception of flooding. Specifically, the perceived number of drought years significantly increases the likelihood of adopting no-tillage/reduced tillage and diversified cropping in the future. However, the number of drought years is not significantly associated with the use of cover crops and integrated crop-livestock grazing. These results suggest that the effects of extreme weather events on adoption of conservation practices as adaptive measures vary across different practices. Therefore, adaptation policies that make use of conservation practices must be tailored to farmers’ needs and priorities to be effective.

Uticaj ozimih međuuseva i različitih jarih useva na strukturu zemljišta tipa černozem

The intensive form of agricultural production often leads to disruption of physical, chemical and biological properties of the soil. Therefore, in recent years there has been an increasing focus on research and finding ways to preserve the soil with management practices that support soil conservation. The research was conducted on the experimental field of the Institute for Field and Vegetable Crops Novi Sad on Rimski Šančevi. The experiment was set up as a randomized block design. The winter cover crops consisted of the combined intercrops: Triticale (×Triticosecale Wittm. ex A. Camus) and winter pea (Pisum sativum ssp. arvense L.) (T+P), solo winter fodder pea crop (Pisum sativum ssp. arvense L.) (P) and a control without winter cover crops (sole or mixtures)(Ø). The experiment with winter cover crops was divided into two blocks. In the first block, the winter cover crops were chopped and plowed, while treatments in the second block were mowed using a rotary mower and the fodder was removed for feeding ruminants. After ploughing and preparing the soil for sowing, sowing of spring crops (soybean, maize and sudan grass) was carried out on all varieties in the subsequent sowing period. This research aims to determine the influence of different types of winter cover crops and spring crops from subsequent sowing period on the physical properties of Chernozem with a special emphasis on soil structure. It was determined that values of MWD on the treatments where the mixture of cover crops (T+P plowed) ranged from 1.11 mm to 1.39 mm, which indicated a better aggregates stability compared to the control treatments where no cover crops were sown. Due to variable root morphology and water requirements, which may alter soil structure, it is required to pay more attention to the adaptation of management strategies through the use of cover crops as well as the selection of their mixes.

Influence of Smallholder Farmers' Socio-economic Characteristics on and Perceived Benefits of Organic Agriculture Farming

The decision to adopt an agricultural technology is categorized into characteristics specific to farmers and their households and socio-economic factors. The difference in factors influencing the smallholder farmers' adoption of Organic Farming (OF) practices varies across the world. Thus, this paper investigates the influence of smallholder farmers' socio-economic characteristics on the adoption of OF in Kisii Central, Kisii County. The study adopted mixed-method research that involved a household survey and key informants. The results indicate that the major socio-economic characteristics influencing smallholder farmers' adoption of organic farming were farm size (79%), income (73%), family size (67%), and age (66%). In addition, there is a positive correlation between education and the use of crop residues (r=0.113), animal manure (r=0.114), and cover crop (r=0.121). The study recommends that promoters of OF consider specific socio-economic characteristics of the farmers in adopting OF.

Agronomic and economic implications of cover crop and phosphorus fertilizer management practices for water quality improvement.

Phosphorus (P) fertilization practices and winter cover crops are promoted to protect water quality yet can potentially influence crop yield and profitability. This study examined the impacts of three P fertilizer management practices (no P, fall broadcast P, and spring injected P) and winter annual cover crop use on yields, net returns, and water quality in a no-till corn-soybean rotation. Treatments were replicated in a 4-yr field study where sediment, total P, and dissolved reactive P (DRP) losses in edge-of-field surface runoff were continuously monitored. Production budgets were developed for each treatment and coupled with water quality data to identify optimal practices and opportunity costs for improving water quality. Applying P fertilizers increased crop yield regardless of application method or cover crop, but the response was more pronounced in corn than soybean. The cover crop reduced corn grain yield in 1 yr with high temperature and low precipitation but did not impact grain yield in the other corn year or either year of soybean. The most profitable treatment was fall broadcast P fertilizer with no cover crop, which also had the greatest total P and DRP losses and near greatest sediment loss. The lowest-cost methods of reducing total P, DRP, and sediment losses were, respectively, no P fertilizer without a cover crop ($47.56kg-1 total P), spring injected P fertilizer without a cover crop ($56.47kg-1 DRP), and spring injected P fertilizer with a cover crop ($0.16kg-1 sediment). Widespread adoption of these practices will likely require monetary incentives.

Evaluating the Effectiveness of Catch Crops and Tillage Systems for Carbon Farming

In modern agriculture, it is necessary to identify strategic steps that will reduce greenhouse gas emissions: on the one hand, reducing emissions by cutting down fuel consumption, reducing soil interference, limiting nitrogen losses when using fertilisers, and on the other hand – increasing the efficiency of carbon extraction from the atmosphere through plant photosynthesis and sequestration as organic matter of the soil. The purpose of this study is to figure out the influence on the carbon balance of such elements of the agricultural system as the system of tillage and the use of intermediate cover crops in a model 4-field crop rotation in the Steppe zone of Ukraine. This work was performed using the method of empirical calculations based on the online calculator of greenhouse gas emissions Cool Farm Tool. The influence of intermediate crops in two fields of crop rotation (after the early grain predecessors – wheat and winter barley) and tillage systems (traditional, reduced, and no-till) on the balance of carbon emissions and sequestration in the model 4-field crop rotation was analysed. According to the results, it was found that during the model 4-field crop rotation under the conditions of the classical system of tillage for sunflower and maize without intermediate crops and reduced processing for wheat and barley, the total greenhouse gas emissions amount to 4015 kg/ha of CO2 -eq. in 4 years. Switching to a reduced tillage system has been shown to reduce emissions by 30.1%. The addition of two intermediate crops in two crop rotation fields before spring crops allows obtaining a negative balance of greenhouse gas emissions of -377 kg/ha of CO2 -eq. during this period, and when switching to no-till for all crops -1221 kg/ha of CO2 -eq. for a 4-year rotation period. This study will help identify strategic steps and their potential contribution to the development and implementation of agricultural systems with minimal greenhouse gas emissions

Arbuscular mycorrhizal fungi in the soil using cover crops with and without nitrogen addition.

This study aimed to evaluate the occurrence of mycorrhizal fungi and glomalin content in soil under different cover crops with and without the application of nitrogen in the cover. The following cover plants were used: Crotalaria juncea (Crotalaria juncea L.), wild beans from Ceará (Canavalia brasiliensis Mart. ex Benth.), Guandú 'BRS mandarin' [Cajanus cajan (L.) Millsp.], millet 'BR05' [Pennisetum glaucum (L.) R.Br.] and sorghum 'BR 304' [Sorghum bicolor (L.) Moench]. The absolute control of the experiment was the treatment without the use of cover crops, that is, the vegetation of spontaneous occurrence in the area. The experimental design was randomized blocks in subplots with three replications. Spore density, mycorrhizal colonization rate, easily extractable glomalin, and species present in the rhizosphere of the cover crops were determined. No differences were found in the diversity of mycorrhizal fungi associated with the different cover crops studied or in the values of spore density, root colonization, or glomalin content. Nitrogen application did not influence the mycorrhizal activity in the investigated cover crops. The most frequent species associated with cover crops were Scutellospora pellucida and Scutellospora persica in C. juncea; Gigaspora sp. on Sorghum; Glomus macrocarpum in Guandu; G. macrocarpum and Glomus clavisporum in millet; and Glomus microaggregatum and Glomus tortuosum in Spontaneous Vegetation.

Cover crops in coffee management in production

Cover crops between rows of coffee contributes to the promotion of a sustainable production. The objective of this work was to evaluate the improvement of the chemical and physical attributes of the soil and coffee production using cover crops between the coffee lines. This study was at Boa Esperança Farm, Serrania – MG. The experimental design consisted of randomized blocks, with 7 treatments and 4 replications: control, no cover plant, with traditional farm management (chemical and mechanical weed control); crotalaria (Crotalária spectablis); cuandu (Cajanus cajan); cowpea (Vigna unguiculata L. Walp.); mix of crotalaria + cuandu + cowpea; Brachiaria brizanta (Urochloa brizantha) and Brachiaria ruzizienses (Urochloa ruzizienses) as cover plants. The data were submitted to analysis of variance by the Scott-Knott test at 5% probability. Results confirm that cover crops promote cycling and nutrient accumulation in the soil, maintain a mild temperature and promoted better moisture maintenance. It also demonstrated that although the population dynamics of weeds have a positive result, only the use of cover crops is not enough for 100% weed control in the coffee crop. Besides, they have a contribution to the development and production of coffee and to reduce the phytonematoid population.

Plant diversity and cattle grazing affecting soil and crop yield in tropical sandy soils

ABSTRACT The use of cover crops and increased plant diversity in agricultural systems can improve soil quality. The objectives of this study were to evaluate the short-term impacts of plant functional diversity and cattle grazing on: (i) soil organic C and N stocks and their fractions, (ii) soil microbial biomass and activity, (iii) enzymatic activity, and (iv) soybean yield in sandy soils of the Brazilian Cerrado. The experiment consisted of four systems, with soybean as first crop followed by: (i) fallow (Very low diversity); (ii) single grass as cover crop (Low diversity); (iii) MIX with palisade grass intercropped with Niger, turnip rape, crotalaria, and estilosantes as cover crops (Medium diversity); and (iv) MIX under cattle grazing (High diversity). The High diversity system had the higher soil total N stock (1.32 Mg ha−1), and a microbial biomass C, microbial quotient, and soybean yield 146%, 147%, and 20% higher than the other systems. The increase in soil microbial biomass and enzymatic activity accounted for the higher soybean yields in the systems. These results demonstrate the potential for soil quality improvements and soybean yield with greater functional plant diversity and cattle grazing in sandy soils of the Brazilian Cerrado.

Effects of Cover Crops and Drip Fertigation Regime in a Young Almond Agroecosystem

The sustainability of woody crop agroecosystems requires continued improvements to water, nutrient and soil management. In this work, the combination of resource availability or fertigation dose with soil management practices was tested in a 2 × 2 factorial design in a drip irrigated young almond orchard. The fertigation doses were: the farmer supply at 60% of crop evapotranspiration and full nutrient requirements and the half-farmer supply at 30% of crop evapotranspiration and half nutrient requirements. The soil management practices were: bare soil and cover crops in the inter-row (mixture of grasses and legumes). Tree growth, yield, water and nutrient status, and cover crop biomass and nutrient status were determined, as well as inter-row soil C and N concentration. Results showed that the effect of resource availability was independent of soil management and vice versa. The half farmer treatment reduced tree vegetative growth and yield compared to farmer treatment, due to a negative effect on the water status, without observing a decrease in the concentration of nutrients in leaves or fruit. Trees with cover crop also reduced growth and yield compared to bare soil management. This was due to a nutritional competition, mainly of Ca, Fe, Mn and Zn, rather than to a decline in tree water status. Cover crops sequester up to 1 t/ha/year of carbon but do not increase soil organic carbon, nor soil total nitrogen. Cover crops proved to be efficient in reducing soil nitrate concentration in the topsoil and therefore has potential to prevent its leaching. Deficit fertigation and the use of cover crops can be effective practices to preserve and save water and nutrient resources in Mediterranean agroecosystems, but should be established with caution so as not to compromise the profitability of the orchard.

Effects of innovative long-term soil and crop management on topsoil properties of a Mediterranean soil based on detailed water retention curves

Abstract. The effectiveness of conservation agriculture (CA) and other soil management strategies implying a reduction of tillage has been shown to be site-dependent (crop, clime and soil), and thus any new soil and crop management should be rigorously evaluated before its implementation. Moreover, farmers are normally reluctant to abandon conventional practices if this means putting their production at risk. This study evaluates an innovative soil and crop management (including no-tillage, cover crops and organic amendments) as an alternative to conventional management for rainfed cereal cropping in a calcareous soil in a semi-arid Mediterranean climatic zone of Navarra (Spain), based on the analysis of soil water retention curves (SWRCs) and soil structure. The study was carried out in a small agricultural area in the municipality of Garínoain (Navarre, Spain) devoted to rainfed cereal cropping. No other agricultural area in the whole region of Navarre exists where soil and crop management as proposed herein is practiced. Climate is temperate Mediterranean, and the dominant soil is Fluventic Haploxerept. Within the study area there is a subarea devoted to the proposed soil and crop management (OPM treatment), while there is another subarea where the soil and crop management is conventional in the zone (CM treatment). OPM includes no-tillage (18 years continuous) after conventional tillage, crop rotation, use of cover crops and occasional application of organic amendments. CM involves continuous conventional tillage (chisel plow), mineral fertilization, no cover crops and a lower diversity of crops in the rotation. Undisturbed soil samples from the topsoil and disturbed samples from the tilled layer were collected for both systems. The undisturbed samples were used to obtain the detailed SWRCs in the low suction range using a HYPROP©device. From the SWRCs, different approaches found in the literature to evaluate soil physical quality were calculated. The pore-size distribution was also estimated from the SWRCs. Disturbed samples were used in the laboratory to assess soil structure by means of an aggregate-size fractionation and to perform complementary analysis from which other indicators related to soil functioning and agricultural sustainability were obtained. The approaches evaluated did not show clear differences between treatments. However, the differences in soil quality between the two forms of management were better observed in the pore size distributions and by the analysis of the size distribution and stability of soil aggregates. There was an overabundance of macropores under CM, while the amount of mesopores (available water) and micropores were similar in both treatments. Likewise, more stable macroaggregates were observed in OPM than in CM, as well as more organic C storage, greater microbial activity, and biomass. The proposed management system is providing good results regarding soil physical quality and contributing also to the enhancement of biodiversity, as well as to the improvement in water-use efficiency. Finally, our findings suggest that the adoption of the proposed practice would not result in a loss in yields compared to conventional management.

Effect of mustard cover crops on corn growth, yield and soil water storage in southwest Texas

Mustard cover crops can provide multiple soil health benefits but may adversely affect cash crops by depleting soil water. This was tested in a center-pivot irrigated corn cropping system in southwest Texas from 2018 to 2020. Changes in biomass growth of both the cover crops and corn, and soil water content in the root zone were monitored multiple times during the main growth periods of the crops. Upon termination, biomass production of cover crops averaged 4271 kg/ha, with equivalent nitrogen and phosphorus inputs to the soil of 92 kg/ha and 12 kg/ha, respectively. Over 2 years, water use during the main growth period of the mustard cover crops and the fallow area averaged at 1.4 mm/day and 1.1 mm/day, respectively, and water use of corn following the mustard and fallow averaged at 4.0 mm/day and 3.7 mm/day, respectively, although the differences were only marginally significant. Our data suggest that water use of cover crops was affected by their growth patterns. The mustard cover crops depleted soil water in a dry year (2019–2020), but to a less extent in a wet year (2018–2019). In either year, however, corn yield was not reduced in association with cover crop use, although the improved shoot biomass growth in corn associated with mustard cover crops was observed in the wet year but not in the dry year. Mustard cover crops tended to reduce deep drainage during the corn seasons, which has implications in preventing the leaching loss of nitrogen in the crop root zone.

Italian Ryegrass, Perennial Ryegrass, and Meadow Fescue as Undersown Cover Crops in Spring Wheat and Barley: Results from a Mixed Methods Study in Norway

Cover crops could provide environmental benefits in spring-grain systems through diversification, reduced nitrate leaching, and carbon sequestration. However, few farmers apply the technique, partly as they believe the cover crops will compete with the main crop and cause yield losses. Cover crops can either be sown together with the grain (undersown) or in autumn and establish after grain harvest. The current study uses a mixed-method approach combining field trials, interviews, and literature synthesis. The field trials focused on perennial ryegrass (Lolium perenne L.), Italian ryegrass (Lolium multiflorum Lam.), and meadow fescue (Festuca pratensis L.) that were undersown with 15 kg ha−1 but with different seeding dates in spring wheat and barley. The interviews focused on gathering practical experiences from farmers in Norway and the literature synthesis gathered results from other studies. For carbon sequestration, nine studies were judged relevant for our target climate and included in our synthesis. They showed a median value at 264 kg C ha−1 year−1. In our field trials, 300–900 kg DM ha−1 year−1 was produced, with Italian ryegrass sown at the same date as the grain on top. Our trials showed no significant grain yield reduction due to the use of cover crops. However, our synthesis of the literature showed a 5–10% yield reduction with Italian ryegrass that was sown at the same time as the grain. One- or two-weeks delay in the sowing of Italian ryegrass, or reduced seeding rates, could reduce the problem. The interviews showed that farmers do not prefer undersown species, especially not perennial species, as they have experienced that such species may come up again in the following years and cause a weed problem. We recommend farmers to use cover crops and for undersowing, we recommend Italian ryegrass that is sown one or two weeks after the grain. Perennial ryegrass can also be recommended, as long as the growth is properly terminated.

Water quality effects of cover crop, grazing and tillage implementation in a long-term no-till wheat system

Agricultural anthropogenic nitrogen (N) and phosphorus (P) continue to be major surface and subsurface water pollutants in developed countries. Integrated crop-livestock systems in the semi-arid Texas Rolling Plains are characterized by continuously cultivated monoculture combined with grazing. Improperly managed grazing can increase soil compaction, and subsequently, decrease infiltration, which leaves the soil exposed to erosion. Grazing is therefore of paramount importance to water quality. Cover crop (CC) use improves soil ecosystem services and functions. The objective of the current study was to characterize soil water quality following CC under continuous wheat (Triticum aestivum), grazing, tillage, and no-till practices under a typic Haplustepts, Rotan clay loam soil type. Treatments evaluated include 1) conventional tillage without a CC (CT); 2) no-till without a CC (NT); 3) no-till with a CC (NTC); and 4) no-till with a grazed CC (NTCG). Portable rainfall simulators were used to assess surface runoff water quantity and quality after CC implementation in a long-term no-till continuous wheat system. Cover crop treatments, both grazed and un-grazed, reduced the amount of runoff by 4–6 times compared to no CC treatments (NT and CT). Converting 12-year-old NT to CT reduced infiltration by at least 43 % and increased runoff by 58 % compared to long-term NT. Consequently, total solids load and concentration for CT were 4–14 times greater than all NT treatments (NT, NTC, NTCG). Conventional tillage (CT) also increased total P loads and concentrations by 2–11-fold compared to all NT treatments (p < 0.05). Rainfall events occurring within three weeks after CC termination resulted in about 6 times greater soluble reactive P (SRP) (except NTCG) and about 2–3 times greater dissolved organic C (DOC) concentrations from CC treatments than non-CC treatments, although this was not observed for subsequent runoff events. Tilling the soil had more deleterious effects compared to flash grazing CC. Adopting NT, either alone, or long-term in combination with CC (either flash grazed or un-grazed) are potentially sustainable viable practices in semiarid regions that can reduce environmental contamination.