| Studying on the distribution and loss characteristics of soil organic phosphorus component under different fertilization practices is necessary to reveal phosphorus cycling mechanism and control the phosphorus loss environmental risk of organic amendments application in the lime concretion black soil area of Huang-Huai-Hai Plain in China.Based on a 38 years long-term experiment,the treatments of no fertilization,conventional fertilization,chemical fertilizer plus low quantity crop straw,chemical fertilizer plus high quantity crop straw,chemical fertilizer plus pig and cattle manure were designed to compare crop yields,soil nutrient contents,and soil organic phosphorus component evolution and loss characteristics,in order to explore the sustainable practice of organic amendments utilization.The main results are as follows:（1）Soil organic matter and hydrolyzed nitrogen are the key factors affecting crop yields.Long-term organic amendments application can effectively improve soil fertility and crop yields of the lime concretion black soil.The effect of adding cow manure is the most obvious,and the yields of wheat and soybean were increased by 17.2%and 60.9%compared with conventional application,respectively.The contents of soil organic matter and hydrolytic nitrogen under the cattle manure treatment were increased by 118.3%and64.8%,respectively.（2）The distribution of organic phosphorus component in the lime concretion black soil is affected by fertilization practices and organic amendments types.Compared with conventional fertilization,increasing straw treatment significantly increased the content of soil labile organic phosphorus by 189.9%（p<0.05）,pig manure treatment significantly increased the content of soil moderately labile organic phosphorus by 210.4%（p<0.05）,and cow manure treatment significantly increased the content of highly stable organic phosphorus by 134.0%（p<0.05）.Generally,the application of straw or pig manure has a better effect on improving the soil organic phosphorus activity,and cattle manure has a stronger effect on the soil organic phosphorus stability.（3）The amount of soil total organic phosphorus at topsoil were shown an increasing trend,and the change rate of soil organic phosphorus under conventional fertilization was8.94 mg·kg-1·a-1.Long-term organic amendments application could increase the accumulation rate of soil total organic phosphorus.Long-term pig manure application could increase the accumulation rates of labile and moderately labile organic phosphorus,and cow manure could increase the accumulation rates of highly stable organic phosphorus.The change rates of soil different organic phosphorus components were closely related to the types and quantities of exogenous organic amendments.（4）Compared with conventional fertilization,the concentrations of dissolved total phosphorus,phosphate and dissolved organic phosphorus were significantly increased after long-term farmyard manure application（p<0.05）.The corresponding concentrations were increased by 300.0%,345.0%,225.0%and 582.8%,648.1%and 474.0%after long-term pig and cattle manure application,and the proportion of dissolved organic phosphorus has been increased,the proportional allocation of phosphorus loss was also changed.In contrast,crop straw incorporation can significantly reduce soil phosphorus loss and decrease the risk of agricultural non-point source phosphorus pollution.Overall,long-term organic amendments application can effectively increase crop yield and improve soil fertility.The effects of pig manure and cattle manure are better than that of straw returned,and pig manure can effectively increase the activity of soil organic phosphorus.Cattle manure application can improve the stability of soil organic phosphorus.However,long-term pig manure and cattle manure application can aggravate the environmental risk due to the increasing of soil organic phosphorus loss.In comparison,crop straw incorporation can effectively guarantee crop yield,improve soil fertility and reduce the organic phosphorus loss risk,which is an environmentally friendly way of organic fertilizer cultivation. |
