减氮配施有机物质对麦田土壤性质和小麦产量的影响

探究氮肥减量配施有机物质的情况下对氮素利用状况及土壤肥力和小麦产量的影响,为我国华北平原区小麦生产中提高氮肥利用效率、实现节肥增效提供理论基础。通过田间试验,设置5个处理：不施氮肥(CK)、农民习惯施氮肥(FN)、减氮20%(80%FN)、减氮20%+生物有机肥(80%FN+OM)、减氮20%+生物炭(80%FN+BC),研究小麦生长关键期土壤容重、有机质、NO₃^-—N和土壤微生物多样性的变化,测定小麦产量并计算氮素利用效率。结果表明,土壤容重受施入有机物质影响显著,成熟期0—20,20—40 cm的80%FN+OM、80%FN+BC的土壤容重较80%FN分别下降3.83%～4.58%和2.96%～5.07%。成熟期0—40 cm的土壤有机质均以80%FN+OM最高,较其他施氮肥处理提高2.13%～18.81%。土壤NO₃^-—N受施氮肥影响显著,挑旗期80%FN+OM和80%FN+BC处理的0—40 cm土壤NO₃^-—N较高;灌浆期80%FN+BC处理的0...

Effects of Nitrogen Reduction Combined with Organic Matter on Soil Properties and Wheat Yield

The nitrogen (N) use status and soil fertility and wheat yield were studied under the condition of reduced urea N input and combined with organic matter, to provide a theoretical basis for winter wheat cultivation in the North China Plain, in terms of improving the N use and fertilizer efficiencies. Field trials were carried out with five treatments:no N application (CK), farmer N application (FN), 20% reduction N application (80% FN), 20% reduction N application with bio-organic manure (80% FN+OM), and 20% reduction N application with biochar (80% FN+BC). In the study, the responses of soil bulk density, organic matter, NO₃^--N, microbial diversity, yield, and N utilization of wheat were measured under winter wheat-maize rotation systematically. The results showed that soil capacity was significantly influenced by the application of organic matter. Compared with 80% FN, the soil bulk density in 80% FN+OM and 80% FN+BC were decreased by 3.83%~4.58% and 2.96%~5.07% in 0-20 and 20-40 cm at maturity stage, respectively. Soil organic matter content of 80% FN+OM was higher than other treatments, and greater by 2.13%~18.81% with 80% FN+OM than N fertilizer treatments in 0-40 cm at maturity stage. Soil NO₃^--N was significantly affected by the application of N fertilizer. Soil NO₃^--N was higher in 80% FN+OM and 80% FN+BC than other treatments in 0-40 cm at flag raising stage. Soil NO₃^--N content with 80% FN+BC was higher than other treatments in 0-80 cm at grouting stage. The soil NO₃^--N residues of FN treatment was higher than other treatments at maturity. Combined application of organic matter could improve soil microbial diversity, increase the number of bacteria OTU, balance the relative abundance of bacteria, and stabilize the soil micro ecological environment. The wheat yield and N agronomic efficiency with 80% FN+OM were 1.09%~7.34% and 2.78%~41.49% higher than other N application treatments, respectively. In the perspective of soil physical and chemical properties, N reduction combined with bio-organic manure rather than with biochar could promote soil quality through increasing soil physical and chemical properties, soil microbial diversity, and wheat production. It is recommended that scientific application of N fertilizer combined with organic matter could improve the sustainable utilization of soil.