为探明西辽河平原玉米秸秆还田年限对土壤物理分组有机碳含量和玉米产量的影响，以秸秆不还田地块（CK）为对照，选取玉米秸秆全量还田3年（HT3）、5年（HT5）、7年（HT7）和9年（HT9）地块，研究浅埋滴灌下秸秆连年还田土壤物理分组有机碳含量和玉米产量的差异性变化特征。结果表明:随秸秆还田年限的增加，0-30cm耕层土壤密度有机碳、颗粒有机碳和团聚体有机碳含量均逐年增加；土壤密度有机碳和颗粒有机碳均表现为HT9、HT7显著高于CK，土壤密度分组有机碳和颗粒分组有机碳含量HT9、HT7平均较CK提高了54.2%、48.1%和48.6%、39.8%；土壤团聚体有机碳含量2-0.25mm粒径最高，>2mm粒径次之，<0.053mm粒径最低，不同粒径土壤团聚体有机碳含量均表现为HT9、HT7显著高于CK，HT9、HT7平均较CK提高了47.5%、37.8%；产量HT9与HT7的差异不显著且二者均显著高于HT5、HT3和CK，HT9、HT7、HT5和HT3分别较CK增产16.9%、14.8%、7.70%和6.86%。西辽河平原玉米浅埋滴灌水肥一体化下，玉米连作秸秆连年还田可有效提高耕层土壤物理分组有机碳含量和玉米产量，且以秸秆连续还田9年效果为最佳。

To explore the effects of straw returning for consecutive year on content of organic carbon in soil physical group and maize yield under the shallow buried drip irrigation in the Xiliaohe plain, the plots with maize straw fully returned to the field for three years (HT3), five years (HT5), seven years (HT7) and nine years (HT9) were selected to investigate the characteristics of different changes of soil physical grouping organic carbon content and maize yield using the plot without maize straw returning as control (CK). The results showed that the content of soil density organic carbon, particulate organic carbon and aggregate organic carbon in 0-30cm soil tillage layer improved with the increase of straw returning year; the content of soil density organic carbon and particulate organic carbon increased significantly in HT9 and HT7, with an average increase of 54.2% and 48.1% in soil density group organic carbon and 48.6% and 39.8% in particulate group organic carbon content compared to CK; the organic carbon content of soil aggregates was highest in the particle size range of 2-0.25mm, followed by>2mm and lowest in the particle size range of<0.053mm, and the organic carbon content of soil aggregates with different particle sizes showed that HT9 and HT7 were respectively significantly higher than that of CK, with an average increase of 47.5% and 37.8% compared to CK; the difference in yield between HT9 and HT7 was not significant, and both were significantly higher than HT5, HT3 and CK which increased by 16.9%, 14.8%, 7.70% and 6.86% compared to CK. Under the integration of water and fertilizer of shallow buried drip irrigation in Xiliaohe plain, maize continuous cropping and straw returning to the field for consecutive years effectively improved the content of soil physical organic carbon in tillage layer and maize yield, and the best effect was achieved by straw continuous returned to the field for 9 years.

内蒙古科学自然基金面上项目(2024MS03012)；国家自然科学(32060435)；内蒙古自治区直属高校基本科研业务费项目(GXKY25Z004)