Rye–Vetch Mixture Proportion Tradeoffs: Cover Crop Productivity, Nitrogen Accumulation, and Weed Suppression

Abstract

Cereal-legume cover crop mixtures have the potential to combine the unique strengths of the component species while taking advantage of interspeci c synergies. However, the relative proportion of each species in the mixture is likely to in uence species interactions and entail important tradeo s in cover crop performance. e objective of this study was to evaluate how the relative proportions of cereal rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth) sown in mixtures in uenced cover crop biomass production, winter annual weed suppression, vetch winter survival, and vetch N 2 xation as measured by the 15 N natural abundance method. Following a replacement series design, treatments consisted of a gradient of seven rye-vetch mixture proportions ranging from 100% vetch to 100% rye. Density and biomass composition in the mixtures were highly correlated with rye and vetch seeding rates, with little evidence of substantial interspeci c interference. Total shoot biomass in all mixtures was equal to or greater than that of either monoculture, but no di erences were detected in vetch winter survival or the e ciency of N 2 xation. Changing the proportions of rye and vetch in the mixtures resulted in tradeo s related to N and weed management goals. Increasing vetch in mixtures led to greater xed N accumulation but also increased seed costs and reduced winter annual weed suppression. A greater understanding of how rye-vetch mixture proportions in uence cover crop performance can support more-informed decision-making regarding cover crop selection and mixture seeding rates.

Cover Crop-Based, Organic Rotational No-Till Corn and Soybean Production Systems in the Mid-Atlantic United States

“…The use of a grass in combination with a legume cover crop can improve N-release synchrony. Prior to termination, grass cover crops may take up N produced by legumes, while after termination, the higher C:N ratio of grasses moderates the leaching potential of the low C:N-ratio legumes [64,65]. Recent research in Maryland demonstrated that mixtures of hairy vetch and cereal rye, residues of which have a substantively higher C:N ratio than hairy vetch alone, can slow the decay rate of cover crop residues and reduce the quantity of early season plant-available N in the soil while still providing an important source of N for corn later in the season [52,58].…”

Nitrogen Benefits of Winter Cover Crop and Fall‐Applied Poultry Litter to Corn

“…In many instances, these trade-offs can be predicted from the characteristics and proportions of individual component species. For example, total N accumulation of biculture residues and winter rye tissue N concentration have been positively correlated with legume proportions in rye/hairy vetch (Vicia villosa Roth) bicultures (Hayden et al, 2014). Recovery of residual soil NO 3 --N by bicultures has been shown to be intermediary between rye and legume monoculture CC (Ranells and Wagger, 1997).…”

“…However, the biculture residue N content, grain yield, stover N, and grain N tended to fall between those values for Legume and Rye and ultimately resulted in an FNEQ similar with that of LegumePL by Year 3. While grass-legume biculture with PL may not consistently have as high FNEQ as LegumePL, there are benefits and tradeoffs when managing bicultures including N retention, weed suppression, and management costs (Brainard et al, 2011;Hayden et al, 2014).…”

Soil Water Balance and Water Use Efficiency of Dryland Wheat in Different Precipitation Years in Response to Green Manure Approach

“…Due to their unique ability to fix atmospheric N 2 via root nodules and produce substantial biomass and nutrient accumulations, the legume green manure (LGM) has become one of the most common and widely studied crop in the worldwide various agro-ecosystems. It has been demonstrated in different regions of the world that LGMs within a cropping system can (i) improve the grain yield of the subsequent cereal crops141516, (ii) provide net additions of N1718, maintain soil fertility and biological activity19, and (iii) reduce N fertilizer application needs2021. Consequently, growing the LGMs during the summer fallow period and incorporating them into the soil at a suitable stage is a viable method to maintain the nutrients, soil structure, and subsequent crop growth and yield.…”