| 摘要: |
| 【目的】探讨关中平原小麦-玉米轮作体系中，秸秆机械化全量还田条件下减量施N对作物产量、土壤碳库及NO3--N累积的影响，为该地区粮食生产的合理氮肥用量提供理论依据。【方法】2008-06-2012-06在陕西关中平原进行了4年田间定位试验，在作物秸秆全量还田条件下，设置了常规施N（玉米和小麦季施N量分别为188，150 kg/hm2）、15%减量施N（玉米和小麦季施N量分别为160，128 kg/hm2）、30%减量施N（玉米和小麦季施N量分别为130，105 kg/hm2）3个处理，对3个处理的玉米和小麦秸秆、籽粒产量以及植物全氮、土壤硝态氮含量、土壤有机碳及活性有机碳含量进行分析。【结果】与常规施N处理相比，15%减量施N有一定增产效果，作物周年籽粒产量可提高7.2%；且30%减量施N处理并未显著减少小麦和玉米籽粒产量以及小麦秸秆产量。减量施N处理明显降低了土壤NO3--N累积量，且根据表观氮平衡结果，N肥施用量仍可减少。减量施N处理对土壤有机碳及活性有机碳含量均无显著影响。随着每季作物秸秆还田以及土壤有机碳含量的逐年增加，活性有机碳含量显著增加。【结论】在秸秆还田条件下适量减N，不仅能保证作物不减产，而且还可逐步增加土壤有机碳含量，降低土壤NO3--N累积量，达到环境效益和经济效益的统一。 |
| 关键词: 秸秆还田 减量施氮 作物产量 土壤碳库 氮素残留 |
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| 基金项目:国家“十二五”科技支撑计划项目(2012BAD14B11)；西北农林科技大学创新团队项目(2010) |
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| Effects of nitrogen fertilizer reduction on crop yields,soil nitrate nitrogen and carbon contents with straw returning |
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LI Jin,TIAN Xiao-hong,WANG Shao-xia,et al
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| Abstract: |
| 【Objective】Effects of nitrogen (N) fertilizer reduction on crop yields,soil carbon pool and NO-3-Naccumulation with straw returning in winter wheat-summer maize rotation system in Guanzhong Plain were studied to determine the optimal N application rate.【Method】A four-year field experiment was conducted during 2008-2012.There were three N treatments in this experiment:conventional N application rate (188,and 150 kg/hm2 in maize and wheat growing seasons,respectively),15% N reduction (160 and 128 kg/hm2 in maize and wheat growing seasons,respectively),and 30% N reduction (130 and 105 kg/hm2 in maize and wheat growing seasons,respectively).Straw and grain yields and total N concentrations of maize and wheat,soilNO-3-N content,soil organic carbon content,and labile organic carbon content were analyzed.【Result】15% N reduction increased crop year-around seed yields by 7.2%,and 30% N reduction did not decrease either wheat and maize grain yields or straw yields compared to conventional N treatment.Accumulation of NO-3-N in soil was significantly decreased with N reduction and N application rate could be further reduced based on apparent N balance.N reduction treatments did not affect soil organic carbon and active organic carbon.The soil organic carbon increased significantly year by year as the returning of straw to soil and increase of soil active organic carbon.【Conclusion】Appropriate reduction of N fertilizer with straw returning could increase soil organic carbon and decrease NO-3-N accumulation without affecting crop yields. |
| Key words: straw returning to soil nitrogen reduction crop yield soil carbon pool residual N in soil |
