Cover Crops Impact Crops Yields by Improving Microbiological Activity and Fertility in Sandy Soil

Abstract

Sandy soil often has low soil organic matter (SOM) content, cation exchange capacity (CEC), and water storage levels. Sandy soil requires specific management techniques to improve soil quality. The purpose of this study was to evaluate chemical characteristics and microbial activity of sandy soil, as well as the effects of different rotation systems on crop yield in these environments. The treatments consisted of cultivation with cover crops in the off-season. The following cover crop treatments were used: fallow, a single grass species (SG), two grass species (G + G), mixture of three or more crop species (MIX), and a grass and legume combination (G + L). Corn and sorghum yields were highest with the fallow treatment. Cotton yield was highest with fallow and G + G treatments. Soybean yield was lowest with the SG treatment. The use of SG resulted in the highest SOM content in the 0–10 cm layer. Phosphorus (P) content was highest in treatments with the lowest biomass content (fallow and G + L); potassium content and CEC levels were highest in treatments with cover crops. The G + L resulted in levels of dehydrogenase and enzyme activity (DEA) that were 50% higher than the fallow. When compared with the fallow, the MIX increased microbial biomass carbon (MBC) and nitrogen (MBN) by 66 and 90%, respectively. The implementation of cover crop systems in sandy soil under no-till improved microbial soil activity even in the first year, but benefits to yield and soil chemistry occurred only after the third year of cultivation.