Fall Broccoli Production following Summer Cover Crops in Louisiana

Multiyear studies were initiated to assess summer cover crops for use in fall vegetable crops in the Deep South.  The research in Louisiana involved the production and incorporation of summer cover crops on the same site followed by fall-planted broccoli in 2012.  The summer cover crop treatments consisted of Sunn hemp, Crotalaria juncea; sesame, Sesamum indicum; a mix of the Sunn hemp and sesame; sorghum–sudan grass, Sorghum bicolor x S. bicolor var. sudanese); and a weed-free check. The cover crop plots received a single irrigation after planting, but received no fertilizer or pesticides prior to or during growth.  A 0.5 m² area of crop and weed shoot mass was harvested at 60 days. Data collected from the second year of the study included cover crop fresh weight and biomass, total nutrient content, and soil organic matter and nutrient content.  Crotalaria had the highest biomass and was statistically greater than the biomass produced by the sesame or sorghum-sudan grass cover crop treatments at harvest.  The effect of different rates of organic fertilizer (composted chicken litter), in combination with summer cover crops, was studied for the production of broccoli.  Cover crop treatment did not affect broccoli yield nor was there an interaction with organic fertilizer treatment. The control unfertilized treatment resulted in no marketable broccoli heads while the 2x, and 3x rate plots had the highest marketable yield and marketable broccoli head weights.