Effects Of Returning Straw To Fields With Fertilizer On Soil Properties And Loss Of Nitrogen And Phosphorus

The direct burning of straw will cause serious resource waste and environmentalpollution. Applying of fertilizer in great quantity will not only cause the loss of soilfertility, but also cause pollution to groundwater and rivers and lakes, and it is theimportant source of agricultural non-point source pollution. So it is particularlyimportant and urgent to study on straw returning and fertilizer optimization using.6treatments of pot experiment and3treatments of field experiment were conducted tostudy the influence of straw returning and its combination with inorganic fertilizer onsoil properties and the loss of nitrogen and phosphorus. The results were as follows:(1) Three treatments: Straw returning, combination of optimizing fertilizationand straw returning, optimizing fertilization with less fertilizer could improve the soilwater content of0-20cm soil layer, but they did not have obvious effect on the soilwater content of20-40cm soil layer. Two treatments of straw returning and thecontrolled treatments of no straw returning could significantly reduce soil bulkdensity of0-20cm soil layer, but they did not have obvious influence on20-40cmsoil layer. Three treatments:no straw returning, no fertilizer and no straw returning,optimization fertilization had obviously different effect on soil bulk density in0~20cm soil layer.(2) Three treatments: Straw returning, combination of optimizing fertilizationand straw returning, optimizing fertilization with less fertilizer could improve contentof total nitrogen、total phosphorus、total potassium、 alkali-hydrolyzable-N、quick-acting phosphorus and quick-acting potassium in soil. Compared with thetreatment of no straw returning, the content of total potassium in soil although hadobvious difference between3treatments, but did not improve much. In the treatmentsof straw returning, content of total nitrogen、 total phosphorus、alkali-hydrolyzable-N、quick-acting phosphorus in soil had the trend of increasingwith growing of wheat.The content of total potassium and quick-acting potassium insoil achieved the peak On December28,2012, then they reduced gradually.(3) Four treatments: combination of straw returning and traditional fertilization,combination of straw returning and traditional fertilization with less fertilizer,combination of straw returning and optimizing fertilization, combination of strawreturning and optimizing fertilization with less fertilizer could obviously improve theorganic matter content in soil when compared with the treatment of no straw returning.(4) The treatment of straw returning could significantly reduce the total nitrogencontent of surface runoff, and three treatments: straw returning, combination ofoptimization fertilization and straw returning, optimization fertilization with lessfertilizer had significant effect on the total nitrogen content in surface runoff. At thesame time, straw returning can reduce total phosphorus content in surface runoff. Butunder the condition of straw returning, the difference of fertilizer quantity had nosignificant effect on total phosphorus content. Straw returning and no strawreturning could significantly reduce the content of total nitrogen, alkali-hydrolysablenitrogen, total phosphorus, available phosphorus in erosion sediment. Under thecondition of straw returning, with the different amount of fertilizer, the above materialcontent in erosion sediment also reached the significant difference level.