Some agriculture practices are unsuitable in the northern hilly region of the Chinese Loess Plateau and have resulted in the degradation of the native vegetation ecosystems and unfavorable soil hydraulic properties, which cause serious soil losses. The objective of this study was to ascertain the influence of land use changes on soil infiltration rate and other related soil properties in this region. A total of 90 infiltration tests were run on six different land uses (natural grassland, apple orchard, abandoned apple orchard, farmland wheat, farmland maize, and scrub grassland). For studying the infiltration rate, a triplicate of infiltration tests had been taken using a disc permeameter with different pressure heads. Infiltration rate was high in abandoned apple orchard (10 mm min⁻¹) whereas very low in apple orchard (0.6 mm min⁻¹). The statistical analysis showed that the main soil properties were affected by changes of land use types or vegetation cover. Compared with that in the natural grassland and abandoned apple orchard sites, a notable reduction of soil root biomass, infiltration, and bulk density in apple orchard was recorded. The root image analysis showed that the natural grassland and abandoned apple orchard have strong root systems, that is, root length density 6.97 ± 0.344 cm cm⁻³, root surface area 1.56 ± 0.24 cm² cm⁻³, and average root diameter 0.814 ± 0.24 mm, in comparison with other sites. The limited root length density, root surface area, and average diameter were recorded in apple orchard 0.51 ± 0.03 cm cm⁻³, 0.49 ± 0.12 cm² cm⁻³, and 1.88 ± 0.24 mm. Conclusively, our study suggests that converting farmland apple orchard into grassland or scrubland may change soil hydraulic properties, which may help to reduce soil losses in the Loess Plateau.

中文翻译：

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黄土高原地区不同土地利用方式对土壤水力特性的影响

在黄土高原北部丘陵地区，一些农业实践是不合适的，并导致了原生植被生态系统的退化和不利的土壤水力特性，造成了严重的土壤流失。这项研究的目的是确定该地区土地利用变化对土壤入渗率和其他相关土壤特性的影响。在六种不同的土地用途（天然草地，苹果园，废弃的苹果园，农田小麦，农田玉米和灌木草地）上进行了总共90次入渗测试。为了研究渗透率，已使用具有不同压头的圆盘渗透仪进行了三次渗透测试。在废弃的苹果园中渗透率很高（10 mm min ^-1），而在苹果园中则很低（0.6 mm min ^-1）。统计分析表明，主要土壤性质受土地利用类型或植被覆盖度的变化影响。与天然草地和废弃苹果园相比，苹果园土壤根生物量，入渗量和容重显着减少。根图像分析表明，天然草地和废弃的苹果园具有强大的根系，即根长密度6.97±0.344 cm cm ^-3，根表面积1.56±0.24 cm ²  cm ^-3。与其他部位相比，平均根直径为0.814±0.24毫米。有限的根长密度，根表面积和平均直径为记录在苹果园0.51±0.03厘米厘米^-3，0.49±0.12厘米² 厘米^-3，和1.88±0.24毫米。总之，我们的研究表明，将农田苹果园转变为草地或灌丛可能会改变土壤的水力特性，这可能有助于减少黄土高原地区的土壤流失。