Effects of Cover Crops and Vermicompost on Strawberry Production in the Southeastern United States

Cultural practices, including cover crop rotations and vermicompost addition, are important aspects of sustainable and low-input strawberry production systems. The objective of this study was to examine the effects of summer cover crops with vermicompost and organic fertilizers on strawberry plant growth, yield, and soil nitrogen levels in a two-year field experiment. The experiment design was a split plot randomized complete block. The main plot factor was a cover crop treatment (six factors) and a vermicompost treatment (two factors) was the sub-plot, split factor. Cover crop treatments consisted of 1) pearl millet [Pennisetum glaucumgenus (L.) cv. Tifleaf 3]; 2) soybean [Glycine max (L.) Merrill cv. Laredo], 3) Cowpea [Vigna unguiculata (L.) Walp. cv. Iron & Clay]; 4) pearl millet/soybean and 5) pearl millet/cowpea, and 6) a no cover crop control treatment. Vermicompost treatments consisted of vermicompost (VERM) added at planting or not (CONTROL). ‘Camarosa’ (2009) and ‘Chandler’ (2010) strawberry plugs were transplanted into plasticulture beds. Cover crop and vermicompost treatments were assessed for their impact on plant growth and yield, weed abundance, and inorganic NO₃^--N and NH₄⁺-N levels. While cover crops had no effect on yield either year, the amount of N supplied through cover crops with reduced rates of strawberry season applied fertilizers appeared to balance the effect of using supplemental fertilizers only in a production system using organic practices. Use of vermicompost improved strawberry biomass and yield, and soil N content. Based on our findings, fertilizer application rates recommended for conventional production in the southeastern United States exceed the N requirements for strawberries when cover crops and organic amendments are used.