Doses of fertirrigated potassium in tomato cultivation in a semihydroponic system

Growing tomato plants with fertigation in sand substrates allows growers to maintain optimal levels of water and nutrients for crop production. This practice also reduces risk from phytopathogens and the development of saline conditions. Potassium (K) is the most required nutrient by the crop.This research evaluated the nutritional influence of potassium on the development of tomato plants during the beginning of the reproductive stage. After the opening of the first flowers, tomato plants are limited by potassium (K) availability. Five doses of K (60, 120, 180, 240, and 300 mg dm-3of K) were applied via fertigation through drip tape in a greenhouse environment, beginning during the flowering stage. The parameters evaluated were: productivity, electrical conductivity (EC) of leachate, Total Soluble Solids (TSS), index nutritional leaf and concentration of nutrients in leaves, stems, and fruits.The data were analyzed using variance analysis and the averages were tested using polynomial regression analysis. The highestyield (99.0 t ha-1) was obtained from plants receiving the highest dose of K. The same plants had the highest concentration of TSS (3.87 ̊brix), as well as the highest levels of K and S in the stem leaves and fruits. The results showedthat an increase in the dose of K prompted an increase in nutrients, TSS, and yield.