Optimization of irrigation and N-fertilizer strategies for cabbage plasticulture system

Florida cabbage production is dominated by a bare ground production with sub optimal plant populations under seepage irrigation system. Previous studies used plasticulture to increase the plant population and maximize cabbage production per area. The present research was conducted to; determine the optimum nitrogen fertilizer application rate range, determine the transport and fate of applied nitrogen fertilizer and to examine the effects of two irrigation strategies for the proposed plasticulture system with high plant population. The soil moisture sensor based irrigation treatment used 11% and 33% less irrigation water in 2013 and 2014, respectively compared to the evapotranspiration based irrigation with no significant difference in cabbage yield. In 2014, the soil moisture sensor based irrigation also led to an increased retention time of nitrogen fertilizer in the crop rootzone. The optimum fertilizer rate range was determined to be between 400 and 570 kg ha−1 of N (5-7 g plant−1 of N), respectively. Cabbage yields obtained using fertilizer rates within the optimum range under high plant population plasticulture were on average 71% greater than the average bare ground yield under seepage irrigation.