Cabbage Yield As Function of Plant Population Cultivated on Plasticulture

Florida cabbage production in northeast Florida covers about 5,500 acres which represents 56% of the planted area for cabbage in the state and produces 30,100 lb/ac on average. In this region water is supplied to the crop using seepage irrigation which relies on a shallow hardpan, high water table, and an abundance of fresh water pumped from the aquifer. Seepage irrigation is an inefficient method for irrigating crops and water distribution throughout the field is typically irregular. Drip irrigation and plastic mulch offer increased water use efficiency through precise application (timing, quantity, and location), reduced soil water evaporation, and reduced weed competition. Cabbage produces have reported that up to 30% of the cabbage planted does not produce a marketable head. Variability in plant growth, uniformity, and head size all contribute to reduced marketable yields. This study focuses on determining if higher plant populations and the use of plastic mulch and drip irrigation can help produce a more uniform crop and increase yield per cultivated area. Cabbage (variety Bravo) was grown on 48-inch wide raised beds spaced 80 inches on center, with black plastic mulch and two drip tapes per bed. Field experiments were conducted during the winter of 2011 and 2012 in Hastings, FL. 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). Final plant population ranged from 14,816 to 46,093 plants/acre. Total fresh yield ranged from 49,500 to 62,800 lb/ac. Marketable cabbage yield (2–4 lb/head) showed a quadratic response to the increase of plant population (Y = –3669.4 + 5.544 x - 0.0001344 x² - R² = 0.85). Plant populations between 17,000 and 22,000 plants/acres (3 rows per bed at 8 and 10 inch in-row spacings and 4 rows per bed at 10 and 12 inch in-row spacings) showed the highest marketable yields. Marketable yield was significantly reduced with 6 inch in-row spacing at both 3 and 4 rows of plants per bed.