Long-term land use and management practices can affect soil organic matter (SOM) and cause changes in soil water repellency (SWR), the extent of which is related to SOM content and composition. Many studies have focused on explaining the generation of SWR and have emphasized the relation between the occurrence and persistence of SWR and SOM; however, few studies have attempted to revisit the amount and quality of SOM based on changes in SWR. In this 10-year study, SWR and SOM were evaluated after traditional tillage versus a one-time straw return, and the effect of traditional tillage on SOM was illustrated through changes in SWR. The findings indicated that SOM and humic acid (HA) contents and the degree of humification decreased by 8.58 %, 24.93 %, and 20.44 %, respectively, after 10 years of traditional tillage. Furthermore, the H/C molar ratio of HA decreased by 13.38 %, and the aliphatic/aromatic C ratio and the hydrophobic/hydrophilic C ratio decreased by 24.05 % and 31.08 %, respectively, resulting in a weakening of HA hydrophobicity. The primary cause for the decline in SWR over extended periods of traditional tillage was the reduction in both the amount and quality of SOM and the decreased hydrophobicity of HA. By contrast, during the initial phase of one-time straw return, there was a notable increase in the amount and quality of SOM and HA hydrophobicity, resulting in a slight water repellency of the soil; however, this increase only lasted for 3 years. The decrease in the degree and persistence of SWR reflects the decrease in the amount and quality of SOM after long-term traditional tillage, which should be supplemented SOM promptly. We recommend supplementing straw again after 3 years of the one-time straw return. By illustrating the correlation between SWR and SOM, we hope to provide land managers with new perspectives regarding SOM, which is negatively affected by long-term land use, especially in soils under long-term traditional tillage.

中文翻译：

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土壤拒水性降低表明，在长期传统农业中需要及时补充土壤有机质


长期的土地利用和管理做法会影响土壤有机质 （SOM） 并导致土壤拒水力 （SWR） 发生变化，其程度与 SOM 含量和组成有关。许多研究侧重于解释 SWR 的产生，并强调 SWR 和 SOM 的发生和持续之间的关系;然而，很少有研究试图根据 SWR 的变化重新审视 SOM 的数量和质量。在这项为期 10 年的研究中，在传统耕作与一次性秸秆还田后评估了 SWR 和 SOM，并通过 SWR 的变化说明了传统耕作对 SOM 的影响。结果表明，传统耕作 10 年后，土壤有机肥和腐殖酸 （HA） 含量以及腐殖化程度分别降低了 8.58 %、24.93 % 和 20.44 %。此外，HA 的 H/C 摩尔比降低了 13.38 %，脂肪族/芳香族 C 比和疏水亲水 C 比分别降低了 24.05 % 和 31.08 %，导致 HA 疏水性减弱。在长时间的传统耕作中，SWR 下降的主要原因是 SOM 的数量和质量的降低以及 HA 的疏水性降低。相比之下，在一次性秸秆还田的初始阶段，SOM 和 HA 疏水性的数量和质量显着增加，导致土壤具有轻微的拒水性;然而，这种增长只持续了 3 年。SWR 程度和持久性的降低反映了长期传统耕作后 SOM 数量和质量的下降，应及时补充 SOM。我们建议在一次性吸管回收 3 年后再次补充吸管。 通过说明 SWR 和 SOM 之间的相关性，我们希望为土地管理者提供有关 SOM 的新视角，SOM 受到长期土地利用的负面影响，尤其是在长期传统耕作下的土壤中。