Soil erosion is a major form of land degradation, especially in agroecosystems, which has been effectively controlled by vegetation restoration. However, the interactive role of erosion and cropland revegetation on soil enzyme activities and microbial nutrient limitations is less understood. To address this issue, we examined carbon (C), nitrogen (N), and phosphorus (P) in bulk soils and microbial biomass, enzyme activities, and microbial nutrient limitations in the 0–200 cm soils in eroded and deposited landscapes occupied by cropland, revegetated forest, and grassland. The results showed that the activities of C-, N-, and P-acquiring enzymes were larger in the deposited landscape than in the eroded landscape for 0–20 cm soils in forest and grassland but not in cropland. Microbial metabolism was co-limited by N and P, and the threshold element ratio (TERL) indicated that P was the most limiting factor. Microbial N limitation was lower in the deposited than the eroded zone, especially in surface soils in revegetated forest and grassland. The TERL value was larger at the deposited than at the eroded zone, and a greater difference was found in the surface soils of forest and grassland. Microbial nutrient limitations were mostly explained by C/P and N/P. Conclusively, the deposited areas were characterized by ameliorated enzyme activities, decreased microbial N limitation but relatively strengthened microbial P limitation compared to the eroded area, and such variations existed in the revegetated forest and grassland but not in the cropland, which thus contributes to a better understanding of C and nutrient cycling for agroecosystems and revegetation ecosystems in eroded environments.

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Aims Cropland revegetation is an effective measure to curb soil erosion on eroding hillslopes and increase farmers’ income at depositional check dams. However, how soil microbial metabolic limitation responds to cropland revegetation in erosion and deposition landscapes remains poorly understood, which has substantial implications for carbon (C) retention and nutrient cycling in the eroding environment. Methods We sampled 0-2 m soils in cropland and revegetated forest and grassland at upslopes and check dams on the hilly-gully region of the Loess Plateau, China. The activities of soil C-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes were analyzed, and the improved V-T model derived from the vector model with the balance point was used to quantify microbial metabolic limitations based on ecoenzymatic stoichiometry. Results Microorganisms suffered from no energy (C) limitation, but the relative microbial C limitation was greater in revegetated land than in cropland in both landscapes. At upslopes, microbial P limitation occurred in the revegetated forest in soils below 20 cm due to the assimilation of P by the root system, while microorganisms were mainly limited by N in cropland and revegetated grassland. At check dams, land-use change had no significant influence on microbial N/P limitations owing to abundant soil C and nutrients and a wet environment. Conclusions Concludingly, this study revealed a non-response phenomenon of cropland revegetation on microbial metabolic limitation at lower-lying depositional topography, which compensates for the current understanding of resource restrictions on microorganisms at slopes or flat areas.