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Cropland soil erosion is primarily caused by agricultural production and indirectly altered by consumption patterns. A well-developed grain trade system transfers grain products to distant locations, away from their place of origin where soil erosion may have occurred. Evidence-based policies to control soil erosion can be developed by holding consumers responsible for the soil erosion caused by their consumption. However, there have been few systematic studies on cropland soil erosion that is embodied in grain trade. In this study, we estimated the soil erosion intensity (SEI) of grain production in each province of China from 1990 to 2020 by combining the Revised Universal Soil Loss Equation and socio-economic statistics. We also constructed an interprovincial grain trade network using linear programming techniques and analyzed the cropland soil erosion associated with the interprovincial grain trade. The results showed a rise in national cropland soil erosion attributed to grain production from 5.36×108 t in 1990 to 7.56×108 t in 2020. In particular, those embodied in interprovincial grain trade increased from 0.94×108 t in 1990 to 3.52×108 t in 2020. Nationally, about 10.72% of soil erosion exports in 2020 was from provinces with lower-than-average SEI, compared to 18.42% in 1990, indicating that current patterns of grain production and consumption are unfavorable for erosion control. Accordingly, measures have been proposed to build a soil erosion control system that includes consumers, such as changing farming practices, optimizing agricultural layout, promoting technology export and establishing a provincial compensation mechanism. [Display omitted] • Trade was prominent and insufficiently explored driver for cropland soil erosion. • RUSLE and grain trade network were utilized to estimate embodied soil erosion. • Mismatch between production and consumption increased embodied soil erosion. • Soil erosion burden mainly shifted from south with high SEI to north with low SEI. • Current provincial grain trade patterns were not conducive to soil erosion control. [ABSTRACT FROM AUTHOR]

In China, sloping farmland accounts for one-third of its total farmland, supporting ~330 million mountain people's livelihoods. Despite its long history of using soil conservation measures for reducing soil loss on sloping farmland, no comprehensive evaluation has ever been performed on their effectiveness. In this study, we reviewed the soil conservation measures on sloping farmland in China from ~2500 years ago to the present and examined their effectiveness under current and projected climate change scenarios based on 6909 plot-scale observations. For the sloping farmland across China, the average soil loss rate is 14.47 Mg ha−1 yr−1, with a quarter of the observed values exceeding the maximum tolerable soil loss rate (10 Mg ha−1 yr−1). Soil conservation measures can reduce soil loss by ~80%, with the highest effectiveness for the combination of biological and engineering measures (reduced by ~86%), followed by biological measures (reduced by ~84%) and engineering measures (reduced by ~82%) separately. However, the effectiveness of soil conservation measures shows a significant decrease in the farmland with a slope above 15° or a single rainfall event >25 mm. The effectiveness of currently applied soil conservation measures was also compared under the Shared Socioeconomic Pathways (SSP) 1, 2, and 5 in 2050, and their effectiveness is expected to decrease on over 27% of the sloping farmland. In particular, under the SSP1 scenario, the effectiveness of soil conservation measures is projected to diminish in 70%, 54%, and 54% of sloping farmland in Northeast China, Sichuan Basin and surrounding regions, and Yunnan-Guizhou Plateau, respectively, due to changes in rainfall, highlighting the need to consider the impact of climate change when implementing soil conservation measures. Overall, this study provides useful information for scientific strategies on the construction, management, and maintenance of soil conservation measures to control soil loss on sloping farmland. [ABSTRACT FROM AUTHOR]

• Land use change significantly reduces the lateral transport of sediment and SOC. • About 21.6–42.9 % of the mobilized SOC is effectively buried behind the check dams. • Soil conservation measures generated significant carbon sequestration effect. • The composition and age of SOC were quantified by radiocarbon isotopes. Human activity is thought to perturb the dynamic change of organic carbon (OC), but its impact on the transportation and redistribution of erosion-induced OC is still poorly understood. Here, we use multi-source field sampling data and long-term hydrological observation data to clarify the transportation and redistribution of OC in an agricultural watershed on the Loess Plateau. The endmember mixing model based on the radiocarbon isotopes (14C) and a budget equation were used to assess the composition and budget of erosion-induced OC in a 187 km2 watershed. The results showed that compared with the period of agricultural activities (1960−1969), soil conservation activities in 1970−1999 and 2000−2019 reduced soil erosion by 31.5 % and 75.4 %, respectively. Additionally, land use changes significantly reduced the mobilized OC, from 14,370 ± 1966 (1960−1969) to 3311 ± 431 Mg C yr−1 (2000−2019). Check dam construction led to the mobilized OC was effectively buried at a rate of 2125 ± 478 and 1420 ± 282 Mg C yr-1 in periods of 1970−1999 and 2000−2019, respectively. Further radiocarbon isotopes analysis shows that the land use changes and check dam construction effectively reduced the output of ancient petrogenic organic carbon (OC petro) and young biospheric organic carbon (OC bio) from the watershed, which has a positive impact on the regulation of atmospheric CO 2 level. Our results emphasize the positive effects of soil conservation activities on terrestrial carbon sequestration, which are of great significance to clarify the effects of soil erosion on the carbon cycle. [ABSTRACT FROM AUTHOR]

[Display omitted] • Accurate quantification of soil erosion sub-process by remote sensing and check dam. • Vegetation restoration significantly reduced soil erosion modulus. • Check dams effectively reduce sediment delivery on the watershed scale. • The variation of erosion and deposition changes the sediment delivery ratio. China has implemented a series of ambitious soil and water conservation (SWC) projects on the Chinese Loess Plateau, which have significantly changed the erosion, transport, and deposition of sediment. As a result, the sediment flux of the Yellow River, once the largest carrier of fluvial sediment worldwide, has been reduced by approximately 85 % in the past 60 years. However, the effects of SWC measures on erosion, transport, and deposition of sediment are still difficult to quantify, which greatly limits the further planning and adjustment of SWC measures. Here, we determined soil erosion, sediment deposition, and sediment yield at different historical stages in a 187 km2 hilly and gully watershed on the Chinese Loess Plateau using the unmanned aerial vehicle (UAV) photogrammetry technology combined with check dam surveying and hydrologic monitoring. The results show that the construction of check dams and vegetation restoration significantly reduced the soil erosion rate, from 21,144 t km−2 yr−1 at Stage-1 (1960–1969) to 13,819 ± 3,622 t km−2 yr−1 at Stage-2 (1970–1999) and further to 4,723 ± 1,278 t km−2 yr−1 at Stage-3 (2000–2018). The sediment deposition rate was estimated to be 5,989 and 2,582 ± 351 t km−2 yr−1 at Stage-2 and Stage-3, respectively. The variation in the erosion and deposition of sediment led to a significant change in the sediment delivery ratio, from 1 at Stage-1 to 0.57 at Stage-2 and 0.45 at Stage-3. Our research results provide an important reference for further SWC planning. [ABSTRACT FROM AUTHOR]

Cropland soil erosion is a major threat to global agricultural sustainability. Compared with the well-studied natural factors of soil erosion, socioeconomic factors have just begun to be considered. The major obstacle is that the soil erosion of different crops has not been accounted for and connected to socioeconomic activities. This study adopted the revised universal soil loss equation (RUSLE) and the environmentally extended multiregional input-output (EE-MRIO) model to account for soil erosion on cropland from the production, consumption, and income perspectives at the provincial and sectoral levels in China. The results showed the major responsible agents in a synthetic view. On the production side, the Yunnan-Kweichow Plateau and surrounding hills of the Sichuan Basin, the Chinese grain bases located in northeastern and central China, and the Loess Plateau were the major regions that caused the most cropland soil erosion. On the consumption side, the national final demand for Sichuan, Yunnan, Shandong, Henan, and other provinces with high production-based cropland soil erosion (PBE) values per se pulled remarkable cropland soil erosion. On the income side, the crucial provinces into which the national primary input enabled notable cropland soil erosion were still those areas with serious cropland soil erosion. From the industrial perspective, the direct effects of human primary inputs into agriculture and the demand for agricultural products played the dominant role. In addition, Cereal and BOP (beans, oil and potatoes) were the most important among the agricultural sectors. The effects of the nonagricultural sectors, especially the manufacture of foods and tobacco (MFT) and the chemical industry (CI), on cropland soil erosion also cannot be ignored. Our results indicated that accounting from multiple perspectives could inform the better management of cropland soil erosion from a more comprehensive perspective. To the best of our knowledge, this study is the first to consider the accounting of cropland soil erosion in China from multiple perspectives. Tailored packages of measures should be established based on different patterns of areas with serious cropland soil erosion. [Display omitted] • Cropland soil erosion accounting was based on a multi-regional input-output table. • Multiple perspectives' accounting shows the major responsible agents for soil loss. • Crops in different regions also were the key to tackle cropland soil erosion. • Cropland soil erosion control cannot just narrow down to four agricultural sectors. • Cropland soil erosion is not a local phenomenon but a macroscopic problem. [ABSTRACT FROM AUTHOR]

• A UAV-based method estimating sediment deposited behind check dams was developed. • Errors of the optimal model for single and regional check dams are 12–13% and 2–3%. • This method avoids limitations of tedious field surveys and historical records. • This method can evaluate sediment retained by check dams in areas as large as 211,800 km2. The estimation of sediment deposited behind dams and reservoirs is of great significance for quantifying soil erosion rate and sediment flux. However, existing methods of sediment volume estimation often require detailed field measurements and historical topographic data, limiting the broader application of these methods. In this paper, focusing on the region that suffers the world's most severe soil erosion, we combine unmanned aerial vehicle (UAV) photogrammetry and simulate submerging analysis to propose a novel method for estimating sediment silted by check dams under complex topography. We obtained 1339 groups of topographic factors and ascertained the corresponding volumes of sediment deposited behind check dams in the loess hilly region of China (LHRC), and established five different models combined with regression analysis. Two different sets of data were used for method validation and optimal model determination. The results showed that the error of the optimal model in the volume estimation of single check dam and regional check dams is 12–13% and 2–3%, respectively. Additionally, the area-volume model has the potential to evaluate the sediment retention capacity of check dams (in the order of billions of cubic meters) in the whole LHRC, because the variables are easy to obtain and the model accuracy is relatively high. The further application of this method will help to evaluate the watershed sediment yield and regional soil and water conservation benefits, and is of great significance for explaining the future changes in water and sediment in the Yellow River basin. [ABSTRACT FROM AUTHOR]

Socioeconomic factors are key driving forces for the occurrence and development of soil erosion, but their effects are not well understood. To analyse the relationship between the socioeconomic system and soil erosion, a framework was proposed and validated with structural equation modelling. Population pressure, economic development, agricultural inputs and outputs and soil erosion are latent variables of the framework. A case study was conducted in Jiangxi Province. The results showed that economic development was the key controlling factor and that agricultural output was the main promoting factor for soil erosion, with path coefficients of −1.321 and 1.609 in 1995 and -0.624 and 0.453 in 2010, respectively. This implied that the contradiction between socioeconomic development and ecological protection was alleviated during the study period. Agricultural input controlled severe soil erosion (-‍0.322) while promoting mild soil erosion (0.095), which indicated that more attention should be paid to the adverse impact of excessive agricultural inputs on soil erosion control. The identification of the socioeconomic driving forces of regional soil erosion could help adjust the development strategy and mitigate the negative effects of economic development on soil erosion control and ecological conservation. • Latent socio-economic variables have considerable influences on soil erosion. • Economic development is the most important driving force of soil erosion. • The promotional effect of surplus inputs on mild soil erosion should be of concern. • Structural equation modelling is a suitable framework to decouple this relationship.. • Contradiction between socio-economy and soil erosion have been alleviated in Jiangxi. [ABSTRACT FROM AUTHOR]

Agricultural production in China is mainly decentralized, small in size, and involved by independent single households. Farmers are the main implementers of soil erosion control projects. Their willingness and abilities, which are crucial to the effectiveness of these projects, are closely related to their social networks. However, the relationship between farmers' social networks and soil erosion control remains unclear. Hengxi, a typical village in Jiangxi Province, China, was used as a case study. Traditional- and new-type of farmers' social networks were built according to the planting structures based on survey data. The results showed that both types of networks had the characteristics of small-world network and scale-free network. The ability to obtain and dispense information was the significant distinction between the two networks. The dealer was an influential key node in both networks. The government agencies were key nodes in the new-type network but not in the traditional-type network, which made it difficult for traditional farmers to obtain indispensable information about soil erosion control. The characteristics of farmers and their corresponding networks had significant influences on their awareness of soil erosion. Soil erosion management projects could be deployed smoothly by the key farmers and government agencies in the new-type social network, but difficultly in the traditional-type social network. To improve the effectiveness of soil erosion control projects, cooperation with dealers is important for government agencies. • Characteristics of farmers' social networks are distinct based on planting structure. • Information diffusion is more efficient in new-type social network. • Betweenness centrality affects farmers' awareness of soil and water conservation. • Government agencies should undertake proper roles in traditional-type social network. [ABSTRACT FROM AUTHOR]