Managing Global Resources for a Secure Future

Few studies have evaluated various legume species mixtures with rye in respect to the consequences for stratification of soil nutrients and microbial activity and composition. Likewise, as industrial hemp Cannabis sativa reappears as a Kentucky agricultural commodity, there have been no studies evaluating cover crop integration with hemp production. The objectives of this study are: (1) demonstrate if differing cover crops and cover crop mixes containing grasses and legumes stratify nitrogen, carbon, and phosphorus with soil depth; (2) determine the change in microbial community in soils planted with individual cover crops and cover crop mixes; (3) show that cover crop use with oil seed hemp production enhances yield and quality; (4) evaluate the effect of hemp on microbial community structure and nutrient stratification. Baseline samples were collected at depths of 0-15 and 15-30 centimeters following a seasonal fallow and a summer annual maize crop. Yield and chlorophyll content of maize, and nutrient analysis and labile carbon of soil showed no significant differences between prior treatments. Cover crop mixes were replanted in fall of 2016.After cover crop termination in May the plots will be planted with hemp variety Santhica 27. I predict that rye treatments will stratify carbon deeper in the soil profile than legumes; total residual and mineralizable nitrogen will be stratified deeper in mixes. Mixes will diversify microbial community structure more than single species. Oil yield and quality in summer hemp will benefit from treatments containing cover crop legumes and suggest potential for reducing N fertilization rates.