施肥模式对淮北平原夏季作物地表径流氮素流失的影响

基于自然降雨条件下夏季作物生长期的野外田间试验,探讨施肥和追肥对作物产量和不同形态氮素径流流失的影响。结果表明,当季不施肥对玉米产量的影响较小,分别明显减少了19.7%和30.4%的玉米总氮径流浓度和流失量;不施肥减少了棉花的产量及径流硝态氮、可溶性氮与总氮的浓度和硝态氮流失量。增加追肥对玉米和棉花的作物产量影响都不明显,却增加了两者的径流硝态氮、可溶性氮和总氮的浓度。与施底肥相比,增加追肥分别提高了69.9%,88.9%和46.2%的玉米硝态氮、可溶性氮和总氮浓度,棉花的相应氮素浓度则分别提高了25.5%,31.8%和37.1%。故在淮北地区土壤和气候条件下,玉米和棉花不追肥及适当减少玉米施肥量既不会使作物减产,又能减少农业土壤氮素随地表径流的流失。

Nitrogen Loss by Surface Runoff from Summer Crops in Huaibei Plain as Affected by Fertilization Modes

Crop yields and runoff nitrogen losses from corn and cotton as affected by fertilization modes were evaluated under natural rainfall.Three fertilization modes,non-fertilizer,base fertilizer(CK) and base fertilizer+side-dressing 2 months after crop planting were investigated for corn and soybean.There were no obvious differences of corn yield between CK and non-fertilizer and of corn and cotton yields between CK and side-dressing.Compared with the CK,non-fertilization reduced runoff total nitrogen(TN) concentration and loss of 19.7% and 30.4%,respectively,for corn;for cotton,non-fertilization reduced runoff nitrate loss and concentrations of nitrate,dissolved nitrogen(DN) and TN.Concentrations of nitrate,DN and TN in runoff of side-dressing treatment were increased by 69.9%,88.9%,and 46.2% for corn,and 25.5%,31.8%,and 37.1% for cotton,respectively,compared with base fertilizer treatment.Therefore,to reduce corn fertilization rates and no side-dressing for corn and cotton appears to be a practical mode for reducing runoff nitrogen loss and maintain crop yield in Huaibei plain.