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• Anticlockwise hysteresis type was the dominating hysteresis type. • Complex hysteresis type generated more sediment than either of three other types. • Antecedent rainfall dominated clockwise type, along with time lag for complex type. • Intraday rainfall and sediment separately dominated clockwise and anti-clock types. • Largest patch index and grassland separately dominated complex and other types. This study aims to quantitatively evaluate the effects of hydrological and landscape characteristics on suspended sediment concentration and discharge (SSC-Q) hysteresis. Runoff and sediment data of 405 flood events were collected from 10 basins in Wudinghe River basin on the Loess Plateau of China. Hysteresis analysis is a key tool for the interrogation of transport of sediment, which have been shown to be important within catchments. It can provide insight into catchment function, allowing the development and testing of process-based hypotheses. The principal components and corresponding explanatory power were extracted quantitatively from hydrological and landscape characteristics via principal component analysis (PCA) and redundancy analysis (RDA), respectively. The most common hysteresis type was anticlockwise. The proportions of the total event sediment loads for different hysteresis types were not always generally correlated to the frequency of the corresponding events. Furthermore, the composition and explanatory power of controlling principal components varied among clockwise, anticlockwise, figure-of-eight, and complex hysteresis types. For hydrological principal components, the antecedent precipitation, intraday precipitation, and sediment principal components controlled clockwise, anticlockwise, and figure-of-eight hysteresis types, which had explained 47.03%, 58.82% and 52.05% of the variation of hysteresis index, respectively; the antecedent precipitation and time lag principal component controlled complex hysteresis type and accounted for 28.22% and 34.65% of the variation of hysteresis index, respectively. For landscape principal components, grassland principal component dominated clockwise, anticlockwise, and figure-of-eight hysteresis types, and accounted for 95.00%, 69.70%, and 92.00% of the variation of hysteresis index, respectively. Largest patch index principal component controlled complex hysteresis type and accounted for 100% of the variation of hysteresis index. Therefore, within this catchment, whereas hysteresis patterns varied due to all of the hydrological and landscape variables to some extent, precipitation, suspended sediment, area of grassland, and the largest patch area had stronger impact on hysteresis dynamics. [ABSTRACT FROM AUTHOR]

Annual atmospheric nitrogen (N) deposition in China increased approximately 8 kg N ha−1 from the 1980s to the 2000s, which may have greatly affected soil respiration (R s) and its temperature sensitivity (Q 10). Although numerous individual studies have been conducted, the responses of R s to simulated N deposition remain controversial. To reconcile the conflicting results of R s and expand our knowledge about the response of Q 10 to N addition, a dataset with 333 independent observations in China was compiled, and a meta-analysis was performed. Our results showed that N addition increased R s by 7.1% (P < 0.05) across all biomes. The positive response degree of R s in croplands (27.0%, P < 0.05) was significantly greater than those in the grassland and forest biomes, which indicated that R s in anthropogenic ecosystems might be more sensitive to N enrichment. In contrast to low and medium N levels (≤20 g m−2 yr−1), high N addition levels (>20 g m−2 yr−1) inhibited R s due to a decrease in plant fine root biomass (RB). Compared with ammonium nitrate, urea is more likely to stimulate the release of soil C. Regression models showed that the R s response ratio (RR) was positively correlated with pH and the RR s of microbial biomass carbon (MBC) and RB. Increases in both plant roots and microbial biomass induced by N addition directly promoted R s , and N enrichment likely increases R s in soil with a high pH. The temperature sensitivity parameter, Q 10 , decreased by 3.7% (P < 0.05) across all biomes and showed an overall negative response for different biomes (except wetlands and deserts), N addition levels and N types. The Q 10 response ratio was positively correlated with the RR of pH. Soil acidification induced by proton release during N fertilizer transformation might accelerate the decomposition of recalcitrant organic matter and further decrease the Q 10 value. Our study provides valuable information to Chinese environmental policy- and decision-makers in their attempts to evaluate the effects of N deposition on terrestrial ecosystem C cycle. • N addition increased R s by 7.1% and decreased Q 10 by 3.7% across all biomes. • Relative to grassland and forest, R s of cropland was more sensitive to N addition. • Contrary to low and medium N addition levels, high N addition levels inhibited R s. • Soil acidification induced by N addition increased R s and decreased the Q 10 value. [ABSTRACT FROM AUTHOR]

Artificial restoring degraded grasslands has shown positive effects on topsoil conservation, leading to reduced soil erodibility and the activation of soil detachment. However, only a few studies have quantified the expected changes in both processes resulting from artificial restoration. In this study, we aim to survey the effects of grassland restoration on soil erodibility and soil loss in alpine degraded hillsides by changing vegetation and soil properties using artificially cultivated. We assessed soil erodibility K-factor (K), mean weight diameter of soil aggregates (MWD), soil saturated hydraulic conductivity (Ks) soil cohesion (Coh) using a structural equation modeling. Our results demonstrated that artificially cultivated grassland restoration effectively reduced soil erodibility on severely degraded hillslopes. The soil erodibility index Coh , MDW and Ks increased by 161.3, 53.4 and 8.6 %, respectively, while K decreased by 5.1 %. Additionally, the artificial grassland proved to be effective in reducing soil loss, with increasing age of artificial restoration. Over the study period from 2019 to 2022, sediment concentration and soil erosion rate decreased by −188.3–41.9 % and from −239.4–20.4 %, respectively. We concluded that artificially cultivated grassland is an efficient approach for reducing soil degradation activation on alpine degraded hillslopes. The findings suggest that this approach could be applicable worldwide under various parent material and climate conditions, providing a promising solution for addressing soil erosion in degraded areas. • Soil erodibility reduced after restoring degraded hillslopes to artificially cultivated grassland. • Soil erodibility index Coh and MDW increased by 161.3 % and 53.4 % after artificial restoration. • Cultivated grassland effectively reduced soil loss with increasing age of artificial restoration. • Sediment concentration and soil erosion modulus reduced by artificially cultivated grassland. • Artificial grassland effectively reduces the activation of soil degradation in alpine hillslopes. [ABSTRACT FROM AUTHOR]