2019 ASHS Annual Conference

Cover crops are used widely in crop rotations for their positive impacts on environmental and biotic conditions that improve subsequent crop production. Cover crop research is often designed to modify a specific environmental or biotic condition using a cover crop application and to describe how that application improves agricultural production. However, as the focus of such research tends to be on the indirect benefits of cover crops on agricultural production, relatively little work is done to understand the basic physiology and ecology of cover crop systems. Indeed, cover crops may be used as environmental indicators to better understand agroecosystem functioning and as a model cropping system to understand crop growth and competition. A cover crop experiment was established in representative agroecosystems of South Florida (vegetable field, commercial grove, tropical fruit collection, natural area) to evaluate the growth and competition of cover crop mixtures in diverse systems. Three sub-tropical cover crops (Crotalaria juncea, Mucuna pruriens, Sorghum bicolor x S. bicolor var. sudanese) and their pair-wise mixtures were planted in a 400m² Latin square (6x6) in May 2018 and November 2018 in each agroecosystem. Plant growth and biomass was monitored through a 90-day and 60-day growth period, respectively. In addition, agroecosystems were classified by local weather, soil, and plant diversity. Crop growth was highly variable among the agroecosystems with higher growth in the tropical fruit collection and natural area systems that had newly cultivated soils with higher organic matter. Within agroecosystems, cover crop mixtures consistently demonstrated higher land equivalent ratio, indicating a complementarity for the cover crops in mixture as indicated by growth and biomass.