Critical Concentrations of Nitrogen, Phosphorus and Potassium in Rice Plant

Abstract

Total land area of paddy plantation in Thailand is approximately eight million hectares. This area has a wide range of soil fertility status. Therefore, nineral nutrient requirements of paddy growing on various soils with different mineral nutrient supplies were investigated at rice experiment stations. Three rates of N, P2O5, and K2O corresponding to O, 37.5, and 75 kg/ha were factorial assigned in four N, P, and K concentrations. The concentrations of N, P, and K in the rice straw which gave satisfactory rice yields were 0.55, 0.06, and 1.00% respectively.