长期施肥稻田土壤基础地力和养分利用效率变化特征

摘要

Objectives]This paper is to study the effects of long-term fertilization on basic soil productivity (BSP), NPK nutrient use efficiency and their relationship in reddish paddy soil under double-cropping rice system.[Methods]A pot experiment based on a long-term fertilizer application was conducted. Three treatments of long-term fertilization were designed including no fertilizer, NPK application and NPK plus rice straws to monitor the impacts of these treatments on yield, BSP (basic soil productivity) yield, BSP contribution rate, NPK absorption rate by rice plants, NPK use efficiency of double-cropping rice, and to analyze the response of NPK use efficiency to BSP contribution rate.[Results]The order of BSP yield and BSP contribution rate for the three treatments was: NPKS > NPK > CK. The BSP yield and BSP contribution rate in double-season rice were increased by 113.8% and 93.7%, respectively, in the NPKS comparing to those in the CK and increased by 100.7% and 81.9%, respectively, in the NPK comparing to the CK. At the same fertilizer application rate, NPFP (N partial factor productivity), PPFP (P partial factor productivity), KPFP (K partial factor productivity), SNDR (soil N dependent rate), SPDR (soil P dependent rate), SKDR (soil K dependent rate), NHI (N harvest index), PHI (P harvest index) and KHI (K harvest index) in the NPKS treatment soil were relatively higher comparing to other treatments, whereas NRE (N recovery efficiency), PRE (P recovery efficiency), KRE (K recovery efficiency), NAE (N agronomic efficiency), PAE (P agronomic efficiency), KAE (K agronomic efficiency) and FCR (fertilizer contribution rate) in the NPKS treatment were relatively lower in the three treatments. NRE, PRE, NAE, PAE, KAE, NPE (N physiology efficiency) and KPE (K physiology efficiency) decreased significantly with the increase of BSPCR (contribution rate of basic soil productivity to yield), while NPFP, PPFP, KPFP, SNDR, SPDR, SKDR increased significantly with the increasing of BSPCR.[Conclusions]Long-term chemical fertilizers application (NPK), especially long-term chemical fertilizer application combined with rice straw (NPKS) could significantly increase the basic soil productivity. In soils with high basic soil productivity, fertilizer application rate can be reduced under the premise of keeping high or stable crop yield and increasing fertilizer use efficiency.%【目的】研究长期不同施肥措施对土壤基础地力和氮磷钾养分吸收利用效率的影响，探明土壤基础地力和氮、磷、钾养分吸收利用效率的相互关系。【方法】采集双季水稻种植制度下33年长期定位施肥试验的不施肥(CK)、施氮磷钾肥(NPK)和氮磷钾肥配施稻草(NPKS)3个处理的土壤，设置施肥与不施肥盆栽试验，监测水稻产量、土壤基础地力产量和基础地力贡献率、水稻氮磷钾养分吸收量、氮磷钾养分利用效率，分析氮、磷、钾利用效率对土壤基础地力贡献率的响应。【结果】早晚稻土壤基础地力产量和基础地力贡献率三个处理土壤大小顺序均为 NPKS > NPK > CK，NPKS处理土壤早晚稻两季平均基础地力产量和基础地力贡献率较 CK处理土壤分别增加113.8%和93.7%，NPK处理分别增加100.7%和81.9%。在同一施肥水平条件下，早、晚稻均以土壤基础地力较高的 NPKS处理氮、磷、钾肥偏生产力，土壤养分依存率，氮、磷、钾素收获指数较高，氮、磷、钾肥回收利用率，肥料农学效率，肥料对产量的贡献率则较低。回归分析表明，氮、磷肥回收利用率，氮、磷、钾肥农学效率，氮、钾素生理利用率均随土壤基础地力贡献率的提高呈显著或极显著降低；氮、磷、钾肥偏生产力，氮、磷、钾素土壤依存率随土壤基础地力贡献率的提高呈显著或极显著提高。【结论】长期施氮磷钾肥或长期氮磷钾肥配施稻草均能提高土壤基础地力，以长期氮磷钾肥配施稻草的效果更显著。在较高基础地力土壤上生产，可以在保证作物高产稳产的情况下实现减量化施肥，实现农业生产的可持续性。