Effects Of Nitrogen, Phosphorus And Potassium Application And Insufficient Irrigation On Rice Yield Of Black Soil

Water and mineral nutrients play an important role in the management of rice production. Many problems exist concerning the nutrient and water management in cool temperate region of Heilongjiang province in north-east China. The objectives of this research were to study the effects of mineral nutrient and water on rice growth.The experiment was located in Minsheng village of Xiangfang district, Haerbin of Heilongjiang province. Soil was classified as black soil, and the cultivar of rice Suijing No. 10. The experiment was designed according the"3414"experimental design principle with three factors,nitrogen, phosphorus and potassium, and four levels for each factor. The experiment was laid out in four replications, 30 mm water from transplanting to tillering, while each block was assigned one water treatment, i.e., 85 % of saturated water content, saturated water content, 30 mm water and 100 mm water.The results were as follows:1) The optimal recommended nitrogen, phosphorus and potassium were respectively 167 kg·ha^-1, 27.9 kg·ha^-1 and 52.8 kg·ha^-1 according to response functions and linear plus plateau methods;2) Nitrogen was the preliminary factor influencing the rice yield, dry matter, and accumulation of nitrogen, phosphorus and potassium;3) Nitrogen and potassium increased significantly the number of productive ear, whereas nitrogen and phosphorus increased significantly the number of grain per ear;4) Insufficient irrigation decreased the weight of per thousand grain, meaning water control after the flowering may damage the yield of rice;5) Optimized nutrient and water was suggested as: controlling the population of rice by nitrogen and phosphorus, while the number of productive ear by nitrogen and potassium, and increasing the weight of per thousand grains by shallow water irrigation after the flowering;6) Thresholds of SPAD were determined as 46.3 for tillering stage and 45.7 for heading stage;7) Under the optimal condition of this experiment, the recovery efficiency of nitrogen, phosphorus and potassium were respectively 39.0%, 21.8 % and 24.8.