Effects of Potassium Rates on Yield and Postharvest Qualities of Winter Fresh Tomato Grown on aCalcareous Soil

摘要

No soil test interpretation for potassium (K) in calcareous soils is currently available to vegetable growers in Miami-Dade County, FL, thus, tomato production has no K recommendation. The objective of this study was to evaluate the effects of K rateson fruit yield and postharvest quality of tomato grown on a calcareous soil in Florida. The experiment was conducted at the University of Florida, IFAS Tropical Research and Education Center, Homestead, FL. Tomatoes were grown using six rates of K: 0,60,100,160,200, and 240 lb/acre of K20 during the 2014 winter season. Potassium fertilizer placement was divided into pre-plant dry fertilizer and fertigation. The responses to K rates were analyzed using regression analysis with four models: linear, quadratic, linear-plateau, and quadratic-plateau. None of the fruit categories at the first harvest were significantly affected by K rates. For the second harvest, the response of total marketable yields was described by linear-plateau model with critical rate of 200 lb/acre. Quadratic regression models predicted maximum extra-large fruit and total season marketable yields at 171 and 185 lb/acre, respectively. The postharvest qualities of tomato fruits were unaffected by K rates. Overall, 200 lb/acre of K,0was sufficient to grow tomato during the winter season on calcareous soils with 81 ppm of ammonium bicarbonate-DTPA exchangeable K in Florida.