安塞新修黄绵土农地有机质分解及土壤有效态养分变化

通过模拟试验研究了安塞黄绵土中有机质分解及土壤有效态养分变化。其结果是:1.土壤中加入的有机质分解率随温度、湿度升高而增加。其分解表现出快速与慢速两个阶段，各阶段的分解量与有机质的化学组成有关。2.土壤中原有的土壤有机质分解速度与半衰期成反比。若不向土壤中施加任何有机质，大约18年左右，土壤中原有的有机质贮量要减少一半。3.新加入的有机质分解时，土壤有效态养分增加。但个别有效态稀土元素在减少。

Decomposition of Organic Matter and Variation of Available Nutrient in Newly Built Farmland of Loessal Soil in Ansai County

The decomposition of organic matter and the variation of available nutrient of Loessal soil in Aasai county were studied by simulated test.The result of this studning is as follows.1.The organic matter decomposing rate of a newly put in soil is increased with the rising of atmosphere and humidity, its decomposing shows two stages of high-speed and slow-speed, and the decomposing amount of each stage is concerned in chemical composition of organic matter.2.The decomposition rate of original soil organic matter is inversely proportional to its half-life.If no organic matter is applied to soil, the storage amount of original soil organic matter would decrease by a half in about 18 years.3.The soil available nutrient would increase while the newly put in organic matter is decomposing,meanwhile,very few rarerarth element of avalable state would decrease.