Soil C-acquiring enzymes are good indicators for the biological mechanism of soil nutrients and organic matter cycles. However, they have been used less frequently to assess the ecological stability and soil C cycle in eroding landscapes due to a lack of knowledge of the responses of C-acquiring enzyme activities to soil erosion and deposition. In the present study, a 3-year field simulation experiment was conducted to examine the variations in the activities of C-acquiring enzymes (β-1,4-xylosidase (βX), β-1,4-glucosidase (βG) and β-D-cellobiohydrolase (CBH)) from erosion-deposition plots with different slope gradients (5°, 10° and 20°) on the Loess Plateau in China (2016–2018). The activities of βX, βG and CBH were higher in the depositional plots than in the erosional plots, and those differences were enlarged with increasing slope gradients. Compared to the 5°-erosional plot, the activities of βX, βG and CBH respectively declined by 3.2–4.5%, 14.3–37.5% and 12.7–29.1% in the 10°-and 20°-erosional plots. The βX, βG and CBH activities were 2.2–18.1%, 17.3–32.1% and 14.8–86.2% higher in the 10°- and 20°-depositional plots than in the 5°-depositional plot. Moreover, the total soil CO₂ emissions from the whole erosion-deposition plots decreased as slopes steepened. The displaced runoff and sediment depleted soil moisture, SOC, clay and microbial biomass in the erosional plots but enhanced these resources in the depositional plots, which can account for the changes in C-acquiring enzyme activities. The spatial distribution of enzyme activities affected soil CO₂ emissions in a positive linear function. The sensitive responses of the C-acquiring enzyme activities and the controlling effects of C-acquiring enzyme activities on soil CO₂ emissions during erosion and deposition processes, should be properly considered in assessing the biological mechanism for nutrition cycling in regions predominated with fragmented eroding landscapes.

获取土壤碳的酶是土壤养分和有机质循环生物学机制的良好指示。然而，由于缺乏对获取C的酶活性对土壤侵蚀和沉积的响应的了解，因此它们很少用于评估侵蚀景观中的生态稳定性和土壤C循环。在本研究中，进行了为期3年的现场模拟实验，以检查C吸收酶（β-1,4-木糖苷酶（βX），β-1,4-葡萄糖苷酶（βG）和β黄土高原不同坡度（5°，10°和20°）侵蚀-沉积图的-D-纤维二糖水解酶（CBH）（2016-2018）。沉积区中的βX，βG和CBH的活性高于侵蚀区中的，且随着坡度梯度的增加，这些差异增大。与5°侵蚀曲线相比，在10°和20°侵蚀曲线中，βX，βG和CBH的活性分别下降了3.2–4.5％，14.3–37.5％和12.7–29.1％。在10°和20°沉积区中，βX，βG和CBH活性分别比5°沉积区高2.2-18.1％，17.3-32.1％和14.8-86.2％。而且，土壤总CO坡度变陡，整个侵蚀-沉积区的₂排放量减少。流失的径流和沉积物耗尽了侵蚀区的土壤水分，SOC，黏土和微生物生物量，但增加了沉积区的这些资源，这可以解释碳捕获酶活性的变化。酶活性的空间分布以正线性函数影响土壤CO ₂排放。在评估以零散的侵蚀景观为主的地区进行营养循环的生物学机制时，应适当考虑C吸收酶活性的敏感响应以及C吸收酶活性对侵蚀和沉积过程中土壤CO ₂排放的控制作用。。