黄淮海平原盐渍土有机质消长规律的研究

7年微区试验表明，在黄淮海季风区内陆盐渍土一年两熟种植制度下，农田土壤有机质平衡含量约为1.50％。在相同的气候，土壤基础肥力，土壤质地条件下，采取不同措施，土壤有机质积累速率不同，到达土壤有机质平衡含量的时间不同。施用碳氮比大，木质素含量高的有机肥，土壤有机质积累快;施用同种有机肥，土壤有机质在达到平衡含量前，有机质的积累量与施肥量呈直线相关。为满足黄淮海平原农田稳产高产和盐渍上抑盐对土壤有机质含量的要求，采用秸秆直接还田，秸秆过腹还田或棉田种植冬牧草，发展畜牧业，增加优质粪肥施用量是提高盐渍土土壤有机质有效措施。

STUDY ON THE REGULAR INCREASE AND DECLINE OF ORGANIC MATTER IN SALT-AFFECTED SOILS OF HUANGHUAIHAI PLAIN

A 7-year miniplot experiment showed that under a cropping system with two harvests in one year and on salt-affected in land soils, the equilibrium content of their organic matter was about 1. 5% in the monsoon climatic region of Huang-huaihai Plain. But the length of time, within which soil organic matter content reached equilibrium, and the rate of accumulation of soil organic matter were different owing to different measures adopted in the same conditions of climate, basal soil fertility and soil texture. The soil organic matter accumulated more rapidly with higher C /N ratio organic manures which contained more lignin. Before its attending to the equilibrium the soil organic matter was linearly correlated with the quantity of organic manures applied.Therefor. in order to meet the requirements of high-stable crop yield in Huang-huaihaiPlain and to control the salt accumulation in the soil surface, the efficoient measures for rapid increase in the organic matter are to lncorporate crop straw into the soil, to apply dung-manure or plant winter -grazing crops in the cotton fields to develop the animal husbandry and to increase the amount of good quality manure.