SOIL FERTILITY CHANGE AS AFFECTED BY NUTRIENT BALANCES IN NEWLY LEVELED FARMLAND

An experiment was conducted in the seashore region of northern Jiangsu to probe the causality of fertility enhancement of the immature soil formed after land leveling with application of some organic manures such as pig manure, cake manure and straws. The result showed that the nutrient output/input ratios increased with the number of cropping seasons on the immature soil. There were significant positive correlations between the contents of soil organic matter and the amount of applied organic material to the soil. The contents of soil total N, available N, available P and available K were also positive correlative with respective nutrient inputs into the soil and with respective nutrient differences between the input and output. It was concluded that inputs of organic material and nutrients were the key factors that controled the fertility evolution of the immature soil.