Our previous studies indicated that ditch-buried straw return (DB-SR) can improve soil processes in the short term, i.e. increasing microbial metabolic capability, reducing nitrogen leaching loss and promoting soil aggregation. However, it remains unclear how long-term implementation of DB-SR affects soil carbon (C) and nitrogen (N) processes and crop yields. Here, the effects of DB-SR on soil C pool and N availability as well as grain yields were investigated after consecutive application of 6 (rice season) and 6.5 years (wheat season). We found that long-term DB-SR significantly increased rice yields, total organic C, NH₄⁺ and NO₃^– in the rice soils, as well as enhanced wheat yields, microbial biomass C, microbial biomass N, microbial biomass C/total organic C ratio and microbial biomass C/N ratio, but reduced NH₄⁺ and NO₃^– in the wheat soils when compared with rotary tillage straw return (RT-SR) and no tillage with straw removal (NT-NS). These findings suggest that long-term DB-SR application has positive effects on grain production, but possibly through different mechanisms in improving soil processes. The yield-increasing effects on rice might result from improvements in soil fertility, whereas increased wheat yields can be ascribed to stimulated soil microbial activity.

我们以前的研究表明，沟埋秸秆还田（DB-SR）可以在短期内改善土壤过程，即增加微生物的代谢能力，减少氮淋失损失并促进土壤聚集。然而，目前尚不清楚DB-SR的长期实施如何影响土壤碳（C）和氮（N）进程以及农作物产量。在这里，在连续施用6年（水稻季节）和6.5年（小麦季节）后，研究了DB-SR对土壤碳库和氮素有效性以及谷物产量的影响。我们发现长期的DB-SR可以显着提高水稻产量，总有机碳，NH ₄ ⁺和NO ₃ ^–在水稻土壤，以及增强的小麦产率，微生物生物量C，微生物生物量N，微生物生物质C /总有机C比和微生物量C / N比，但降低NH ₄ ⁺和NO ₃ ^-中的小麦土壤时与旋转耕作的秸秆还田（RT-SR）相比，无耕作的秸秆还田（NT-NS）。这些发现表明，长期应用DB-SR可以对谷物生产产生积极影响，但可能通过改善土壤过程的不同机制发挥作用。水稻增产的影响可能是由于土壤肥力的提高，而小麦单产的增加可归因于土壤微生物活性的提高。