Proper tillage combined with straw management is crucial for maintaining agroecosystem sustainability and crop yield, especially under intensified agricultural activities. However, the optimal depth for tillage in combination with straw incorporation remains unclear. To address this, we established a field experiment in 2011 in Mollisols with five treatments: conventional tillage (CT, tillage depth 20 cm), no-tillage combined with straw return (SNT), conventional tillage combined with straw return (SCT), inversion tillage combined with straw return (SIT, tillage depth 35 cm), and subsoil tillage combined with straw return (SST, straw depth 20–35 cm). We assessed the effects of these treatments on soil quality by evaluating the Soil Physical Property Index (SPI), Soil Chemical Property Index (SCI), and Soil Microbial Property Index (SMI) in relation to the Soil Quality Index (SQI) and crop yield. Our findings shown that tillage combined with straw return significantly improved soil properties. Compared to the CT, SNT, and SST treatments, the SCT and SIT treatments increased SPI and SQI in the 0–20 cm soil layer by 43.9–845.4 %. While the SIT and SST treatments enhanced SPI, SCI, and SMI in the 20–35 cm soil layer by 69.2–307.7 % more than the CT, SNT, and SCT treatments. Among all treatments, SIT treatment resulted in the highest SPI, SCI, and SMI in the 0–35 cm soil layer. Additionally, SQI and maize yield under the SIT treatment were 11.7–140.5 % and 15.6–78.0 % higher, respectively, compared to other treatments. Linear regression analysis revealed that SPI in all layers had a significant impact on maize yield, while SCI and SMI were significantly correlated with yield only in the 20–35 cm layer (P < 0.05). SPI's contribution to maize yield was 18.6–156.8 % higher than that of SCI and SMI. Partial least-squares path modeling identified SPI as a direct influence on SMI and SCI, making it the largest driver indirectly improving SQI and maize yield in Mollisols. Therefore, SIT treatment is a highly effective soil management practice for improving soil quality and crop yields in the Mollisols region. Our study provides guidance for enhancing soil environmental quality and designing sustainable agricultural policies in the Mollisols region and other arable soils.

中文翻译：

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Mollisols 长期耕作和秸秆掺入对土壤质量和玉米产量的驱动因素


适当的耕作与秸秆管理相结合，对于维持农业生态系统的可持续性和作物产量至关重要，尤其是在集约化农业活动的情况下。然而，秸秆掺入的最佳耕作深度仍不清楚。为了解决这个问题，我们于 2011 年在 Mollisols 建立了一个田间试验，采用五种处理：常规耕作（CT，耕作深度 20 cm）、免耕结合秸秆还田 （SNT）、常规耕作结合秸秆还田 （SCT）、倒耕结合秸秆还田（SIT，耕作深度 35 cm）和底松结合秸秆还田（SST，秸秆深度 20-35 cm）。我们通过评估土壤物理特性指数 （SPI）、土壤化学特性指数 （SCI） 和土壤微生物特性指数 （SMI） 与土壤质量指数 （SQI） 和作物产量的关系来评估这些处理对土壤质量的影响。我们的研究结果表明，耕作与秸秆还田相结合显著改善了土壤特性。与 CT、SNT 和 SST 处理相比，SCT 和 SIT 处理使 0–20 cm 土层的 SPI 和 SQI 提高了 43.9–845.4 %。而 SIT 和 SST 处理对 20-35 cm 土层的 SPI、SCI 和 SMI 的增强比 CT、SNT 和 SCT 处理高 69.2-307.7%。在所有处理中，SIT 处理导致 0–35 cm 土层的 SPI 、 SCI 和 SMI 最高。此外，与其他处理相比，SIT 处理下的 SQI 和玉米产量分别高出 11.7-140.5 % 和 15.6-78.0 %。线性回归分析显示，各层SPI对玉米产量有显著影响，而SCI和SMI仅与20–35 cm层的产量显著相关（P < 0.05）。SPI 对玉米产量的贡献为 18.6-156。比 SCI 和 SMI 高 8%。偏最小二乘路径模型确定 SPI 对 SMI 和 SCI 有直接影响，使其成为间接提高 SQI 和玉米产量的最大驱动因素。因此，SIT 处理是一种非常有效的土壤管理实践，可以提高 Mollisols 地区的土壤质量和作物产量。我们的研究为提高土壤环境质量和设计 Mollisols 地区和其他可耕地土壤的可持续农业政策提供了指导。