Effect of Rotational Planting of Vegetables and Rice with Economic Vegetable Fertilization on N and P in Leached Water of Soil Pillar

Due to different nutritive requirements between the vegetables and early-mature rice, this experimentation studied the effect of a rotational planting of the crops with economic fertilization for the vegetables on soil pollution due to leached N and P. The planting experiment in the field with rotation of kidney beans, cucumber and early-mature rice showed a net income of 145 771 yuanhm-2 in a single cycle, an increase by 29.5% over control, or 9.3% as compared to the conventional practice. At the time when the rice was harvested, the total N and P concentrations in the water in the treatment soil pillar decreased by 14.9% and 7.4%, respectively, as compared to those in the basic soil. The rotational planting of vegetables and rice reduced the N and P requirements of the early-mature rice, besides being environmentally friendly. The N and P recovery rates reached 59.2% and 34.7%, respectively, with the rotational planting. They increased by 6.9% and 6.4%, respectively, over control, or by 20.0% and 23.3%, respectively, over the conventional practice. The new practice improved the N and P utilization by a wide margin resulting in a maximized economic benefit. At the same time, it also decreased the amount of N and P leached into the garden soil minimizing the environmental pollution.