Winter cover crops effect on soil moisture and soybean growth and yield under different tillage systems

Abstract

Current agricultural systems heavily rely on intensive tillage and inorganic fertilizer inputs. This tradition increases the cost of agricultural production and negatively affects agricultural systems and environment. Conservation practices, such as cover crops (CCs) and no-till (NT), could serve as a management approach to promote soil health and agricultural sustainability. There is limited understanding of CCs effect on soil properties, crop growth and yield under different tillage systems in the humid sub-tropical region of the US. This study evaluated the effect of winter cover crops [wheat (Triticum aestivum) and hairy vetch (Vicia villosa)] and different tillage systems [NT and conventional till (CT)] on soil moisture dynamics, plant nutrients, and soybean (Glycine max) growth and yield in a very fine sandy loam soil from winter 2015 to summer 2018. Results showed significant effect of both tillage and cover crops on soil moisture and infiltration rates during soybean production. Average soil moisture content in the 0–15 and 15–30 cm soil depths was 7.9 and 4.3% higher in the CT than in the NT system, respectively. Cover crops increased soil moisture in 0–30 cm depth by 3 to 5% compared to control plots. No-till increased the percolation rate by 20 to 30% at the 20 to 40 cm depth compared to CT. Cover crop biomass yield in 2017 was significantly affected by CC type, tillage system and their interaction. While CCs had no significant impact on soybean height at harvest, CT increased plant height by 25% and 33% compared with NT for 2016 and 2017, respectively. Soybean yield averaged 3.24 Mg ha−1 across years in CT and 3.02 Mg ha−1 in NT system during 2016 to 2018. Vetch tended to produce higher soybean yield compared to wheat and control. Overall, cover crops could improve soil quality and increase crop yield in humid sub-tropical regions, but such effects vary with CCs type and tillage system.