Plasticulture Grown Cabbage: Effects of Plant Population and Planting Dates on Crop Yield

Growers in the major cabbage producing regions in Florida rely on seepage irrigation achieved by the upward movement of water from capillarity resulting from an artificially maintained water table just below the root zone. The water use efficiency of seepage irrigation is typically lower than 50%. Therefore growers are seeking more efficient irrigation methods to reduce crop losses, increase yield, and improve water/nutrient use efficiency. Plasticulture, or the use of drip irrigation and plastic mulch, offers approximately 95% water use efficiency, increased plant population per area, and reduced weed and possibly disease pressure. Cabbage ‘Bravo’ was grown on 48-inch wide raised beds with black plastic mulch and drip irrigation. A split plot design with randomized complete blocks and four replications was used. Main plots consisted of three or four rows of plants per bed and the subplot factors were in-row plant spacing (6, 8, 10, 12, and 14 inches), the final plant population ranged from 16,802 to 52,272 plants per acre. The trial was planted on two dates, 25 October and 06 December 2012. The October planting yielded 15% more marketable cabbage than the December planting. There were significant interactions between planting date and in-row spacing (P = 0.01) and number of rows per bed (P = 0.02) for marketable yield. Wider in-row spacings performed better for the October compared to the December planting. For the earlier planting (October), treatments of 10, 12, and 14 inch averaged 41,700 lb/acre and were significantly greater than 6 and 8 inch in-row spacings. In the later planting (December), in-row spacings of 12 and 14 inch averaged 41,770 lb/acre, which was 17% and 50% higher than the 10 and 8 inch in-row spacings, respectively. The 3 plant rows per bed treatment was unaffected by planting date, whereas the 4 plant rows per bed treatment yielded significantly lower for the December planting. Marketable yield for the 4 plant row per bed treatment averaged 36,960 lb/acre for the October planting, while 27,839 lb/acre for the December planting. In general, higher cabbage marketable yields were obtained with a plant population in the range of 16,802 and 39,204 plants/acre for the October planting and 16,802 and 26,136 plants/acre for the December planting.