Straw return is commonly used to improve soil fertility and quality, thereby contributing to improved crop production; however, the influence of different straw management on soil moisture variation, its response to precipitation, and soil pore properties remains largely inadequate, let alone the relationships between these factors. To fill this knowledge gap, the temporal dynamics of soil moisture were monitored during the maize growing season from 2022 to 2023 in a fixed-site field experiment on straw return, including straw removal (CK), straw direct incorporation (SD) and straw-derived biochar incorporation (BC), in Northeast China. In contrast to CK, BC was observed to have a significant impact on soil moisture, increasing the monthly average of September by 30.3 % and the annual average by 5.90 % in 2022 (P < 0.05). In addition, SD significantly increased the average for June by 28.5 % (P < 0.05) and exhibited a more pronounced linear correlation between soil moisture and rainfall amount with the greatest slope (y = 0.2061x + 0.0026, R² = 0.3098). The results indicated that the soil water storage capacity was enhanced when straw was returned, with a more effective impact in BC in 2022 but in SD in 2023, partially attributing to the discrepancies in precipitation quantity, intensity, and frequency between the two years. Furthermore, BC significantly reduced the dissipated precipitation fraction and enhanced the soil water memory in both 2022 (P < 0.05) and 2023 (P < 0.01), based on the evaluation of the capacity of soil to retain water. The results of X-ray computed tomography (CT) scanning showed that straw return resulted in the reconstruction of a relatively intricate pore network, which was characterized by an increase in porosity and macropore number in SD, an increase in pore circularity, a reduction in pore diameter and maccropore number in BC, which was associated with soil layer depth. It is concluded that the improvement of soil water and pore properties, as evidenced by an enhanced soil moisture memory and an increased porosity, contributed to the enhancement of soil nutrients under straw return conditions. This study provides valuable insights for selecting a suitable mode of straw return, thereby facilitating the effective utilization of straw and water resources in agricultural systems, particularly in arid regions.

中文翻译：

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秸秆还田重构土壤孔隙结构，提高雨养条件下玉米田试验土壤水分记忆


秸秆还田通常用于提高土壤肥力和质量，从而有助于提高作物产量;然而，不同的秸秆管理对土壤水分变化、对降水的响应和土壤孔隙特性的影响在很大程度上仍然不足，更不用说这些因素之间的关系了。为填补这一知识空白，在2022—2023年玉米生长季，在东北地区开展了秸秆还田试验，包括秸秆去除（CK）、秸秆直接掺入（SD）和秸秆衍生生物炭掺入（BC），监测了土壤水分的时间动态。与 CK 相比，观察到 BC 对土壤水分有显着影响，2022 年 9 月的月平均值增加了 30.3%，年平均值增加了 5.90% （P < 0.05）。此外，SD 显著增加了 6 月的平均值 28.5 % （P < 0.05），并且土壤水分与降雨量之间的线性相关性更明显，坡度最大 （y = 0.2061x + 0.0026， R² = 0.3098）。结果表明，秸秆还田后土壤储水能力增强，2022 年对 BC 的影响更大，但在 2023 年的 SD 影响更大，部分归因于两年之间降水量、强度和频率的差异。此外，基于对土壤保水能力的评价，BC 在 2022 年 （P < 0.05） 和 2023 年 （P < 0.01） 显著降低了耗散降水分数并增强了土壤水分记忆。 X 射线计算机断层扫描 （CT） 扫描结果显示，秸秆还田导致重建了一个相对复杂的孔隙网络，其特征是 SD 孔隙度和大孔数增加，孔圆度增加，孔径和 maccropore 数减小，这与土层深度有关。结论是，土壤水分记忆增强和孔隙度增加证明了土壤水分和孔隙特性的改善，有助于在秸秆还田条件下增强土壤养分。本研究为选择合适的秸秆还田模式提供了有价值的见解，从而促进了农业系统，特别是干旱地区秸秆和水资源的有效利用。