Effects Of Soil Baisc Characteristic And Soc Component Of Black Soil Under Long-Term Different Fertilization

Black soil, with an area of1.0×107hm2in all and7.0×106hm2to cultivate, is a main type of cultivated soil in China. It is mainly in the northeast grain producing area, especially in Heilongjiang and Jilin provinces, in which it accounts for50%of the total cultivated area. Since the over intensive cultivation, it faces with degradation in fertility and quality, such as soil organic matter (SOM) decreasing, soil layer declining and nutrient losing, This is a serious threat to the safety of the northeast as well as China’s grain production. So now, scientists are putting more and more attentions to raising the black soil’s fertility.Our research, based on the long-term experiment of national black soil and fertilizer efficiency, studied the effects of long-term fertilization on the black soil fertility and its organic C pools. The conclusions are as follows:Soil fertility was the highest at top and decreased along with the soil depth. Among all fertilization regimes, the effect of NPK was the worst while the NPK+M best. The treatment of NPK+M raised the content of SOC by50.7%, TN by59%, available N by87.4%, available P by45times, and available K by70.32%compared with the Control;Straw recycling and manure application could improve the soil structure by reducing the soil bulk density. So NPK+S or NPK+M could efficiently enhance soil fertility and quality;Corn-soybean rotation could raise the SOC by13.85%, TN by13.02%, available N by16.26%and available K by27.65%compared with corn cropping under NPK+M. However, fewer effects were found on available P, soil moisture and soil bulk density;Long-term fallow showed higher contents of SOC, TN, and available K compared the fertilized plots except manure application, suggesting that field fallow could raise or at least remain soil fertility in Northeast China; NPK+M could raise the percentage of the activity C pool and increase SOC by raising the activity C pool, while the allocation of activity C decreased in the NPK or the Control;Both fallow and NPK+M increased the SOC contents in the large aggregates, which helps C sequestration in soil;Summarily, the combination usage of fertilizer and manure could raise soil fertility and improve soil quality efficiently.