长期施肥下淮北砂姜黑土区小麦产量稳定性研究

【目的】分析长期施肥条件下小麦产量的变化规律，试图探明淮北小麦产量稳定性对不同施肥模式的响应机制，为淮北砂姜黑土合理施肥管理、改善农田生态系统质量提供依据。【方法】以安徽杨柳长期定位试验为研究平台，通过研究小麦的平均产量、产量年际波动及土壤养分状况对5种施肥模式（不施肥、单施化肥、单施有机肥、有机肥与化肥配施（等氮）、有机肥与化肥配施（高氮））的响应，比较不同施肥条件下淮北砂姜黑土区小麦产量稳定性的优劣，并以此评判施肥的合理性。【结果】淮北砂姜黑土区长期不施肥的小麦产量总体呈下降趋势，年下降量为5.81 kg•hm-2；而长期施肥的小麦产量随时间呈锯齿状波动并总体上升的趋势，其中有机肥与化肥配施（高氮）处理（HMNPK）的产量趋势线最高，但其增产优势逐年减弱，有机肥与化肥配施（等氮）处理（MNPK）以9.75 kg•hm-2的年增长量缩短与其的差距；单施化肥处理（NPK）的小麦产量趋势线在试验前期高于单施有机肥（M），但在22年后有被M处理赶超的趋势。从32年小麦平均产量来看，与不施肥相比，有机肥与化肥配施（高氮与等氮）的增产幅度最大，平均产量分别达5 544.3和5 200.6 kg•hm-2；NPK次之，比当年不施肥处理产量提高了614.6%，M增产幅度最低，但与NPK差异并不明显。砂姜黑土地力贡献率在试验前10年持续降低，降至10%左右趋于稳定，而肥料对小麦产量的贡献率则是在前10年持续增加至80%-90%便维持动态平衡。长期不施肥易导致小麦产量变异系数（CV）偏高、可持续性产量指数（SYI）偏低，产量稳定性最低；施肥处理中HMNPK和MNPK处理的CV最低、SYI最高，产量稳定性最高，而M处理的产量稳定性和可持续性不及NPK。与长期不施肥相比，施肥可明显提高淮北砂姜黑土全氮、有机质、有效磷和速效钾的含量，其中有机肥的施入显著提高了土壤全氮和有机质含量，而有效磷含量与化肥的投入相关，处理M土壤速效钾含量较高，但与其他施肥处理差异不显著；通过相关性分析可知全氮、有机质、有效磷含量与小麦产量呈极显著正相关关系（P＜0.01）。【结论】施肥可有效提高淮北小麦产量，且产量随时间呈锯齿状波动；有机肥与化肥配施（高氮和等氮）的增产效果最佳，但高氮与等氮水平间的产量差随种植年限的增长而逐渐缩短；在试验开始前一阶段单施化肥的增产效果优于单施有机肥处理，但在22年后有被赶超的趋势。与长期不施肥相比，有机肥与化肥配施的施肥模式更有利于促进小麦产量稳定性和生产可持续性的提高，其次为单施化肥，单施有机肥最低。施肥可有效提高砂姜黑土养分含量，其中有机肥对有机质、全氮及速效钾含量的提高作用较强，而化肥则对有效磷含量提高作用较强，且小麦产量与全氮、有机质和有效磷均呈极显著正相关关系。因此，安徽淮北砂姜黑土区有机肥与化肥配施为最佳施肥模式，土壤养分供应较均衡，小麦产量幅度最大且稳定性最佳，农田生态系统质量最优。

Study on Wheat Yield Stability in Huaibei Lime Concretion Black Soil Area Based on Long-Term Fertilization Experiment

【Objective】The research was conducted to explore the responsive mechanism of wheat yield stability to long-term fertilization. 【Method】 Based on long-term fertilization experiment in Yangliu village of Anhui province, the trend of change in wheat average yield, annual fluctuation of wheat yield and soil nutrients content in 5 fertilization patterns were investigated: non-fertilization (CK), application of single chemical fertilizer (NPK), application of single organic fertilizer (M), mixed application of organic and chemical fertilizer with the same amount of nitrogen (MNPK), mixed application of organic and chemical fertilizer with the larger amount of nitrogen (HMNPK).【Result】It was discovered that wheat yield in CK showed a declining trend by 5.81 kg•hm-2•a-1, while fluctuated increasing emerged in fertilization treatments. Wheat yield trend line of HMNPK was in the first place, but MPK had been chasing after by 9.75 kg•hm-2•a-1. Wheat yield trend line of NPK was higher than M in the earlier stage of experiment, whereas it was caught up by M after 22 years. In respect of wheat average yield of 32 years, HMNPK and MNPK were higher than other fertilization treatments, with 5 544.3 kg•hm-2 and 5 200.6 kg•hm-2, respectively; NPK took the third place, by increasing 614.6% of that in the non-fertilization treatment; wheat yield increasing of M was the lowest, however, no obvious difference was found between M and NPK. The contribution of soil capacity in lime concretion black soil had been decreasing in early 10 years then stopped and kept stable at 10%; the contribution ratio of fertilizer had been increasing in early 10 years, and then maintained dynamic balance at the level of 80%-90%. It enhanced the coefficient of variation (CV) and reduced sustainable yield index (SYI) without fertilization, which made yield stability the worst; the wheat yield stability of HMNPK and MNPK was better than NPK which was better than M. Compared with CK, fertilizer application increased the content of total nitrogen, organic matter, available phosphorus and available potassium in soil. Addition of organic fertilizer intensified the content of soil total nitrogen and organic matter. Available phosphorus content was related to application of chemical fertilizer. Available potassium content was at the relatively higher level in M, but the differences with other fertilization treatments were not significant. The contents of total nitrogen, organic matter and available phosphorus were significantly positively correlated with yield in Huaibei lime concretion black soil (P＜0.01).【Conclusion】Fertilizer application increased wheat yield significantly in Huaibei. The yield of HMNPK and MNPK were at the higher level, but the yield gap between the two treatments was shortening with growing years. Wheat yield of NPK was higher than M in earlier stage of experiment, while it was caught up with M after 22 years. Compared with CK, mixed application of organic and chemical fertilizer conduced to enhance wheat yield stability and sustainability, NPK took the second place, M placed the last. Fertilization increased soil nutrient content: organic fertilizer enhanced organic matter, total nitrogen, while chemical fertilizer enhanced available phosphorus. Wheat yield correlated positively with total nitrogen, organic matter and available phosphorus significantly. In a word, mixed application of organic and chemical fertilizer is the best fertilization mode in Huaibei lime concretion black soil area, which made soil nutrient more balanced, wheat yield more stable and agricultural ecosystem quality better.