ẢNH HƯỞNG CỦA CÁC YẾU TỐ DINH DƯỠNG ĐẠM, LÂN, KALI LÊN SINH TRƯỞNG, PHÁT TRIỂN VÀ NĂNG SUẤT LÚA TRÊN ĐẤT PHÙ SA SÔNG HỒNG TẠI NAM ĐỊNH

The experiment was conducted in 2011 on the yearly non-reinforced alluvial land of the Red River in Hai Phong commune, Hai Hau district, Nam Dinh province. Research results have shown the role of nutrients such as nitrogen, phosphorus and potassium for clean-bred rice and hybrid rice. If 1 of such 3 nutrients as nitrogen, phosphorus and potassium is not used in the farming, it may not reduce the yield in the spring crop, but obviously it reduces the rice yield in the main crop. For clean-bred rice: without nitrogen used for farming, there will be a 15.64% reduction of rice yield; without phosphorus, there will be a 10.37% reduction of rice yield, without potassium, there will be an 8.08% reduction of rice yield. For hybrid rice: without nitrogen, there will be an 8.10% reduction of rice yield; without phosphorus, there will be an 8.13% reduction of rice yield; without potassium, there will be a 6.44% reduction of rice yield. Without using such aforesaid nutrients, the yield entirely goes down in comparison with the adequate use of nitrogen, phosphorus and potassium in both two crops. In the spring crop, for clean-bred rice, there is a 6.76% reduction and a 10.32% reduction for hybrid rice. In the crop, there is a 23.46% reduction for clean-bred rice and a 25.15% reduction for hybrid rice. If nitrogen, phosphorus and potassium are appropriately combined and used for farming in the spring crop, there will not be clear with yield increase, but the yield increase is very obvious in the crop in comparison with the only use of nitrogen, phosphorus and potassium in the form of mineral fertilizer. During the crop, there will be an 8.01% increase of yield for clean-bred rice and 9.66% increase for hybrid rice.