Optimizing Nitrogen Rates for Seedless Watermelon [Citrullus lanatus (Thunb ) Matsum & Nakai] Production with Fertigation in North Florida: A One-year Case Study

Abstract

New innovative methods are much needed to help growers comply with Basin Management Action Plans (BMAPs) and to improve fertilizer use efficiency for commercial watermelon production in Florida. A field trial was conducted to evaluate the effects of different nitrogen (N) fertilization rates without or with Agrhizome (with SumaGrow) on watermelon yield, quality and soil fertility after harvest. Treatments included were: 0, 75, 112, and 150 lb/acre N without or with SumaGrow (SG). Watermelon were harvested 4 times and °Brix values were determined immediately after harvest. After harvest, soil samples were analyzed to evaluate soil fertility. The application of 150 lb/acre of N without or with SG produced statistically similar watermelon yields of 29.5 and 28.3 t/acre, respectively. Among the N treatments, SG did not make a significant contribution to the total watermelon yield in this trial. Marketable watermelon yield was greatest with 150 lb/acre of N, without and with SG. There was no significant difference among the treatments with respect to °Brix values at the second and third harvests. At the fourth harvest, 75 lb/acre of N produced fruit with the highest °Brix value (11.3). After harvest, soil phosphorus content was not influenced by N fertilizer rates while soil potassium content was highest without N fertilization.