在陕西关中塿土区，通过田间试验研究旱地小麦－玉米轮作条件下有机无机肥配施对表层土壤有机碳（ SOC）、全氮（ TN）和土壤微生物量碳（ SMBC）、氮（ SMBN）以及土壤剖面硝态氮（ NO3－⁃N）分布和累积的影响。结果表明，与单施化肥处理（NP）相比，化肥配施有机肥处理（M1）土壤剖面NO3－⁃N累积量差异不显著，化肥配施生物炭处理（ M3）显著降低35�2％，而化肥配施秸秆处理（ M2）则显著增加32�1％。与NP和CK处理相比，各有机无机肥配施处理（ M1、M2和M3）表层SOC和SMBC、SMBN含量均显著提高（ P＜0�05），土壤TN含量和C／N比增加（ P＞0�05）。与NP处理相比，M3处理SOC含量增加26％，TN含量增加14％；M2处理SMBC和SMBN含量分别增加32％和23％。与CK处理相比，NP、M1和M2处理表层土壤pH值显著降低，而M3处理则无显著差别。在塿土区旱地小麦－玉米轮作条件下，M3处理既可以降低土壤剖面NO3－⁃N累积量和淋溶风险，又可以提高SOC、TN和SMBC、SMBN含量，是一种值得推广的施肥方式。%A field experiment was carried out to explore effects of combined application of organic manure and chemical fertilizations on soil organic carbon, soil total nitrogen and soil microbial biomass C and N in the topsoil layer, and distri⁃bution and accumulation of NO3-⁃N in the soil profile of farmlands under wheat⁃maize rotation on Lou soil in the Guanzhong region, Shaanxi Province. Results show that compared with Treatment NP ( application of chemical fertilizers a⁃lone), Treatment M1 (combined application of chemical fertilizers and farmyard manure) had no significant effects on ac⁃cumulation of soil NO3-⁃N in the soil profile (0-200 cm), while Treatment M3 (combined application of chemical fertiliz⁃ers and biochar) lowered the accumulation by 35�2%, and Treatment M2 ( combined application of chemical fertilizers with straw incorporation) increased it by 32�1%. Compared with Treatments NP and CK, Treatments M1, M2 and M3 in⁃creased the contents of soil organic carbon ( SOC) , soil total nitrogen ( TN) , and soil microbial biomass C ( SMBC) &N (SMBN) and C/N ratio in the topsoil layer. Compared with Treatment NP, Treatment M3 increased SOC by 26% and TN by 14%, while Treatment M2 increased SMBC by 32% and SMBN by 23%. And compared with CK, all the treatments significantly lowered soil pH in the topsoil layer, except for Treatment M3, which did not have much effect. Obviously in the upland fields of Lou soil under wheat⁃maize rotation, Treatment M3 can not only decrease NO3-⁃N accumulation and leaching risk, but also increase the contents of SOC, TN, SMBC and SMBN, therefore, it is a fertilization pattern worth extending.
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