长期施肥措施下潮土土壤碳氮及小麦产量稳定性的变化特征

Variation Characteristics of Soil Organic Carbon,Nitrogen and the Stability of Wheat Yield in Fluvo-Aquic Soil under Long-Term Fertilization

研究了长期不同施肥方式对潮土区土壤有机碳、全氮含量的影响,以期为小麦高产稳产及培肥技术提供指导。以长期定位肥料试验为平台,选择4个处理:不施肥(CK)、氮磷钾化肥(NPK)、氮磷钾化肥配施有机肥(MNPK)、氮磷钾化肥配施秸秆还田(SNPK)。测定1990-2018年间土壤有机碳、全氮含量及小麦产量。结果表明,施肥处理下小麦产量总体表现为上升趋势,其中前18 a SNPK和MNPK处理小麦产量大体上低于NPK处理,后11 a SNPK和MNPK处理大体上高于NPK处理,分别提高8.90%,8.93%。与CK相比,NPK、MNPK、SNPK处理均增加产量的稳定性;在施肥处理中,SNPK处理产量可持续性指数最高,为0.66。拟合方程表明,农田基础地力每增加1000 kg/hm^(2),肥料贡献率降低14.35~19.57百分点。长期施肥能提高土壤有机碳、全氮含量,其中MNPK处理有机碳、全氮提升作用最明显,年均增幅分别为0.158,0.014 g/kg。土壤全氮含量与有机碳含量呈现正相关(R2=0.620),有机碳含量每升高1 g/kg,土壤全氮含量增加0.078 g/kg。施肥可提高小麦产量,提升小麦产量稳定性和可持续性指数。在小麦-玉米轮作体系下,氮磷钾化肥配施秸秆还田最有利于维持可持续生产能力。氮磷钾化肥配施有机肥可有效提高土壤有机碳、全氮含量。在潮土区施有机肥及秸秆还田是提升土壤肥力和保障可持续利用的重要措施。

Investigated the effects of long-term different fertilization methods on soil organic carbon and total nitrogen content in fluvo-aquic soil region,which would provide guidance for obtaining high and stable yield of wheat and technology of fertilizing.Based on the long-term experiment,four fertilization treatments were selected including no fertilizer(CK),chemical fertilizer only(NPK),N,P,K fertilizer plus organic manure(MNPK)and N,P,K fertilizer plus maize straw(SNPK),for determination of soil organic carbon,total nitrogen content and wheat yield from 1990 to 2018.The results showed that wheat yield in fertilization treatments showed a increasing trend,and the wheat yield of SNPK and MNPK treatments was generally lower than that of NPK treatment in the first 18 years,and generally higher than that treated with NPK in the last 11 years,which increased by 8.90%and 8.93%respectively.Compared with CK,the stability of yield under NPK,MNPK and SNPK could increased.In fertilization treatment,the yield sustainable index of SNPK treatment was the highest,0.66.The fitting equation showed that the contribution rate of fertilizer would be decreased by 14.35-19.57 percentage point for every 1000 kg/ha increase in base yield of farmland.Long-term fertilization could increase soil organic carbon and total nitrogen content,and MNPK treatment increased soil organic carbon content and total nitrogen content the most obviously by 0.518,0.014 g/kg per year respectively.The soil total nitrogen content was positively correlated with soil organic carbon content(R2=0.620).Every 1 g/kg of increased in soil organic carbon content would bring an increase of 0.078 g/kg of total nitrogen content.In summary,fertilization increased wheat yield,yield stability and yield sustainable index.SNPK treatment maintained the best sustainable production capacity in the wheat-maize rotation system.MNPK treatment could effectively increase soil organic carbon content and total nitrogen content.Therefore,applying organic fertilizer and returning straw to field in fluvo-aquic soil area are important measures to improve soil fertility and ensure sustainable utilization.