Cover Crop In a Sod-Based System: Agronomic Outcomes and Environmental Benefits.

A sod-based project is developed at the University of Florida, IFAS-NFREC in Quincy to further improve our knowledge of the effect of conservation agriculture on crop productivity, soil fertility, and water quality. Integrating a short-term bahiagrass and cover crops into a row-crop rotation improves soil physical properties and increases soil organic matter. The summer crops in the sod-based rotation are responding better to stresses in both dry and wet years when winter cover crops are grown in-between. The 2-yr sod is having positive effect on nitrogen cycle and the winter cover crop is further decreasing surface runoff and nitrogen losses. Without irrigation seed cotton yields from sod-based rotation were higher than from conventional rotation. Similar trend of increased pod yield was seen for peanut from sod-based rotation in comparison to conventional rotation.  

A higher N concentration in soil solution from conventional rotation exceeded occasionally the USA drinking water standard of 10 mg L^-1, while the sod-based rotation kept it below that level. Nitrogen leaching tended to occur in the wet periods when water fluxes are in line with higher N concentration in the soil solution with N losses up to 22 kg ha^-1 from conventional rotation versus 13 kg ha^-1 from the same crop sequence of the sod-based rotation. A greater seasonal fluctuation was observed under newly planted bahiagrass with potential load up to 40 kg ha^-1. In contrast, less N was leached below the root zone of cotton and peanut from sod-based rotation. The sod-based rotation under conservation tillage improves the use of plant available water by increasing root growth and better utilizing natural resources, which in turn requires fewer external inputs. Compared to conservation-tilled conventional crop rotation, sod-based cropping system can further advance plant growth resulting in higher soil fertility, crop productivity, and environmental sustainability.