短期化肥减施后玉米产量的响应及其驱动因素分析

Analysis of the response and driving factors of corn yield after short-term reduction of chemical fertilizers

新时期绿色农业发展的一个重要方面是实现化肥零增长,减少过量和不合理施用化肥带来的环境问题。我国有机肥和秸秆资源巨大且未被充分利用,化肥减施后配施有机肥和秸秆还田成为实现化肥零增长的主要管理措施之一,近年来受到越来越多的关注。然而,作物产量对短期化肥减施后的响应及其驱动因素尚不清楚,有待进一步研究。以冬小麦-夏玉米典型种植区华北平原开展的田间定位试验(2010-2016年)为平台,研究化肥减施后配施有机肥和秸秆对玉米产量、土壤有机质、养分、pH及酶活性的影响。试验地点位于河北曲周县,共设置4个处理,包括不施肥(CK)、100%化肥(NPK)、70%化肥+30%有机肥(NPKM)、70%化肥+30%有机肥+秸秆(NPKMS)。结果表明:经过6年短期施肥后,施肥处理较CK显著提高了玉米产量,且NPKMS较NPK显著提高了玉米产量8.3%。与NPK相比,NPKM未显著改变土壤有机质含量,NPKMS则显著提高了土壤有机质含量20.6%。与NPK相比,NPKM和NPKMS未显著改变土壤全氮、有效磷和p H。与CK相比,NPK未显著改变土壤酶活性,NPKM和NPKMS则显著提高了土壤酶活性。通过结构等式方程模型分析发现,对玉米产量变异贡献最大的两个因子是土壤有效磷和土壤蔗糖酶活性。有机肥替代30%化肥后进行秸秆还田可提高玉米产量和土壤有机质,是实现减肥并提高土壤肥力的重要措施。

An important aspect of agriculture green development is to realize zero growth of chemical fertilizers and reduce the environmental problems caused by excessive and unreasonable application of chemial fertilizer.In China,the resources of organic fertilizers and straw are huge and underutilized,and the application of organic fertilizer and straw returning to the feild after the reduction of chemical fertilizer application has become one of the main management measures to achieve zero growth of chemical fertilizer,and has received more and more attention in recent years.However,the response of crop yield to short-term fertilizer reduction and its driving factors remain unclear and require forther study.A 6-year field experiment(2010-2016)carried out in the North China plain,a typical winter wheat-summer maize plating area,the effects of reducing chemical fertilizer application and applying reduce organic fertilizer and straw on maize yield,soil fertility,soil pH and enzyme activity.There were four treatments:no fertilizer(CK),100%chemical fertilizer(NPK),70%chemical fertilizer+30%organic fertilizer(NPKM),and 70%chemical fertilizer+30%organic fertilizer+straw(NPKMS).The results showed that fertilization treatment significantly increased maize yield compared with CK,and NPKMS significantly increased by 8.3%compared with NPK.Compared with NPK,NPKM did not significantly change the soil organic matter content,and NPKMS significantly increased soil organic matter content by 20.6%.Compared with NPK,NPKM and NPKMS did not significantly change soil total nitrogen,available phosphorus and pH.Compared with CK,NPK did not significantly change soil enzyme activity,and NPKM and NPKMS significantly increased soil enzyme activity.The analysis of structural equation modelling showed that soil available phosphorus and invertase activitiy were the major driving factors.Returning straw to the field and replacing 30%of chemical fertilizer with organic fertilizer can increase maize yield and soil organic matter,and is an important measure to achieve fertilizer reduction and soil fertility improvement.