Study on the Evolution of Soil Fertility and Fertilization Technology on Yunlianghu Farm of Hubei Province

On the base of the soil investigation in 1981 and 1998,and soil fertility survey in 2007,the analysis of soil fertility and the evolution of fertilization technology were conducted on the Yunlianghu farm in Hubei Province from 1981 to 2007.The results showed that soil organic matter content was declined during 27 years,but the rate of decline slowed from 1981 to 2007;soil available P content was increased in these years,but the changes of alkali-hydrolyzable nitrogen and available potassium contents were the V-shaped trend of decreasing from 1981 to 1998 and increasing from 1998 to 2007.That was because the ecological environment around the soil microorganisms was changed after the groundwater reducing by drainage,soil organic matter was decomposed,available potassium contents were reduced with the decrease of soil water content;the changes of fertilization and cropping patterns,especially the rice straw,wheat straw and cotton-stalk returning after 2000 were also the important factors for the slow decline of soil organic matter content and the improvement of soil available nutrient from 1998 to 2007.