Applying Fertilizers Mixed with Superabsorbent Polymer Improving Growth and Yield of Tomato Grown on Sandy Soil in Florida.

Sandy soils are water repellent due to the property of soil particles, which results in lower penetration and non-uniform movement of water. There is a desirable need to improve the water and nutrient holding capacity of sandy soil. This tomato study was conducted in Citra, FL, fall 2016 to enhance tomato productivity by incorporating superabsorbent polymer (Stocksorb-660) into soil and improving the surface property of soil particles. There were two treatments (1) 30 lbs/acre superabsorbent polymer completely mixed with 160 lbs/acre nitrogen as ammonium nitrate and (2) 0 superabsorbent polymer with 200 lb/acre nitrogen as ammonium nitrate. UF/IFAS recommended phosphate and potash rates were applied. All of the fertilizers and superabsorbent polymer were 100% applied pre-plant. A randomized complete block design was used with three replications. The superabsorbent polymer applied increased tomato fruit yield, number of fruits, plant height, stem diameter, leaf greenness, photosynthetic rate, stomatal conductance, nitrate level in petiole sap, nitrate reductase activity, nitrite reductase activity, relative water contents, nutrient-use efficiency, and fruit quality (citric acid, malic acid, tartaric acid, soluble solid concentration and fruit firmness). In addition, tomato plants treated with the superabsorbent polymer also showed greater concentrations of Ca, Mg, K and P in both of roots and shoots compared to the control. The findings of this investigation indicated that this superabsorbent polymer can improve soil particles’ capacity to hold nutrient and water more effectively; thereby increasing the tomato plant growth and fruit yield. It is suggested that the superabsorbent polymer may become a potential BMP tool for tomato production on sandy soil in Florida but more trials are needed for large scale demonstration.