Effects of returning to field of sweet corn straw on soil fertility，yield and benefit

Stabilizing and improving the soil fertility of cultivated land in sweet corn region，is an important way to realize the sustainable development of sweet corn production. Trough the test of sweet corn straw directly returning to field after 6 season for 3 years，the results showed that continuous single application of fertilizer was not conducive to the stability of soil fertility and yield improvement，implementation of straw returning could improve fertility and soil acidic conditions，enhance the yield of sweet corn. Compared with the control， in the single application of fertilizer treatment，soil available phosphorus increased，while the contents of soil organic matter，available nitrogen and available potassium decreased by 1.08 g/kg，1.18 mg/kg and 2.47 mg/kg respectively，the soil pH decreased by 0.15. The same fertilizer conditions to implement single and double cropping of straw returning，organic matter increased by 0.71 g/kg and 1.29 g/kg，available nitrogen increased by 17.15 mg/kg and 28.27 mg/kg，available phosphorus increased by 0.96 mg/kg and 1.73 mg/kg，available potassium increased by 2.41 mg/kg and 5.92 mg/kg，soil pH increased by 0.16 and 0.2. Compared with the single application of chemical fertilizer，the average yield increased by 7.5% and 11.8%，the average income increased by 87.3 Yuan and 117.1 Yuan per 667 m2.