Comment on “Multi-time scale variability of rainfall erosivity and erosivity density in the karst region of southern China, 1960–2017” by Zhu et al. (2021), “Spatial characteristics of the human factors of soil erosion at the boundary of political divisions: A spatial approach” by Meng et al. (2021), and “Environmental factors influencing spatial variability of soil total phosphorus content in a small watershed in Poyang Lake Plain under different levels of soil erosion” by Han et al. (2020)

CATENA ◽  
2022 ◽  
Vol 211 ◽  
pp. 105976
Author(s):  
Yu-Chieh Huang ◽  
Walter Chen
2020 ◽  
Vol 12 (5) ◽  
pp. 2126
Author(s):  
Lingxia Wang ◽  
Zhongwu Li ◽  
Danyang Wang ◽  
Xiaoqian Hu ◽  
Ke Ning

Soil and water conservation partitioning (SWCP) considers complex environmental statutes and development demands and serves as a scientific basis for conducting soil erosion management and practice. However, few studies have researched partitioning in small watersheds (< 50 km2), and guidelines for enabling region-specific measures are lacking. In this study, the Xiaoyang watershed located in the red soil region of southern China was selected as a representative small watershed in which to conduct partitioning. The pressure–state–response (PSR) model was used as a framework for establishing an indicator system that included soil erosion sensitivity, the soil erosion condition, and ecosystem services. With three soil and water conservation variables as the input layer, a one-dimensional self-organizing map was applied to identify clusters in the small watershed. The silhouette width was evaluated to determine the optimal number of regions. Based on the associated results, the Xiaoyang watershed was divided into five regions accounting for 82%, 9%, 8%, 2%, and 1% of the total area, respectively. This study provides a framework on which region-specific soil erosion measures can be planned, and it also provides a partitioning method that can be employed in other areas.


Solid Earth ◽  
2017 ◽  
Vol 8 (4) ◽  
pp. 721-736 ◽  
Author(s):  
Cheng Zeng ◽  
Shijie Wang ◽  
Xiaoyong Bai ◽  
Yangbing Li ◽  
Yichao Tian ◽  
...  

Abstract. Although some scholars have studied soil erosion in karst landforms, analyses of the spatial and temporal evolution of soil erosion and correlation analyses with spatial elements have been insufficient. The lack of research has led to an inaccurate assessment of environmental effects, especially in the mountainous area of Wuling in China. Soil erosion and rocky desertification in this area influence the survival and sustainability of a population of 0.22 billion people. This paper analyzes the spatiotemporal evolution of soil erosion and explores its relationship with rocky desertification using GIS technology and the revised universal soil loss equation (RUSLE). Furthermore, this paper analyzes the relationship between soil erosion and major natural elements in southern China. The results are as follows: (1) from 2000 to 2013, the proportion of the area experiencing micro-erosion and mild erosion was at increasing risk in contrast to areas where moderate and high erosion are decreasing. The area changes in this time sequence reflect moderate to high levels of erosion tending to convert into micro-erosion and mild erosion. (2) The soil erosion area on the slope, at 15–35°, accounted for 60.59 % of the total erosion area, and the corresponding soil erosion accounted for 40.44 %. (3) The annual erosion rate in the karst region decreased much faster than in the non-karst region. Soil erosion in all of the rock outcrop areas indicates an improving trend, and dynamic changes in soil erosion significantly differ among the various lithological distribution belts. (4) The soil erosion rate decreased in the rocky desertification regions, to below moderate levels, but increased in the severe rocky desertification areas. The temporal and spatial variations in soil erosion gradually decreased in the study area. Differences in the spatial distribution between lithology and rocky desertification induced extensive soil loss. As rocky desertification became worse, the erosion modulus decreased and the decreasing rate of annual erosion slowed.


2019 ◽  
Vol 18 (8) ◽  
pp. 1739-1745 ◽  
Author(s):  
Gabriel Lazar ◽  
Alina Maria Coman ◽  
Georgiana Lacatusu ◽  
Ana Maria Macsim

CATENA ◽  
2021 ◽  
Vol 201 ◽  
pp. 105278
Author(s):  
Xiao Meng ◽  
Jiannong Cao ◽  
Xiaofeng Wang ◽  
Chong Zhang ◽  
Jinsheng Lv

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 39 ◽  
Author(s):  
Lifeng Yuan ◽  
Kenneth J. Forshay

Soil erosion and lake sediment loading are primary concerns of watershed managers around the world. In the Xinjiang River Basin of China, severe soil erosion occurs primarily during monsoon periods, resulting in sediment flow into Poyang Lake and subsequently causing lake water quality deterioration. Here, we identified high-risk soil erosion areas and conditions that drive sediment yield in a watershed system with limited available data to guide localized soil erosion control measures intended to support reduced sediment load into Poyang Lake. We used the Soil and Water Assessment Tool (SWAT) model to simulate monthly and annual sediment yield based on a calibrated SWAT streamflow model, identified where sediment originated, and determined what geographic factors drove the loading within the watershed. We applied monthly and daily streamflow discharge (1985–2009) and monthly suspended sediment load data (1985–2001) to Meigang station to conduct parameter sensitivity analysis, calibration, validation, and uncertainty analysis of the model. The coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), and RMSE -observation’s standard deviation ratio (RSR) values of the monthly sediment load were 0.63, 0.62, 3.8%, and 0.61 during calibration, respectively. Spatially, the annual sediment yield rate ranged from 3 ton ha−1year−1 on riparian lowlands of the Xinjiang main channel to 33 ton ha−1year−1 on mountain highlands, with a basin-wide mean of 19 ton ha−1year−1. The study showed that 99.9% of the total land area suffered soil loss (greater than 5 ton ha−1year−1). More sediment originated from the southern mountain highlands than from the northern mountain highlands of the Xinjiang river channel. These results suggest that specific land use types and geographic conditions can be identified as hotspots of sediment source with relatively scarce data; in this case, orchards, barren lands, and mountain highlands with slopes greater than 25° were the primary sediment source areas. This study developed a reliable, physically-based streamflow model and illustrates critical source areas and conditions that influence sediment yield.


Solid Earth ◽  
2017 ◽  
Vol 8 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Yue Li ◽  
Xiao Yong Bai ◽  
Shi Jie Wang ◽  
Luo Yi Qin ◽  
Yi Chao Tian ◽  
...  

Abstract. Soil loss tolerance (T value) is one of the criteria in determining the necessity of erosion control measures and ecological restoration strategy. However, the validity of this criterion in subtropical karst regions is strongly disputed. In this study, T value is calculated based on soil formation rate by using a digital distribution map of carbonate rock assemblage types. Results indicated a spatial heterogeneity and diversity in soil loss tolerance. Instead of only one criterion, a minimum of three criteria should be considered when investigating the carbonate areas of southern China because the one region, one T value concept may not be applicable to this region. T value is proportionate to the amount of argillaceous material, which determines the surface soil thickness of the formations in homogenous carbonate rock areas. Homogenous carbonate rock, carbonate rock intercalated with clastic rock areas and carbonate/clastic rock alternation areas have T values of 20, 50 and 100 t/(km2 a), and they are extremely, severely and moderately sensitive to soil erosion. Karst rocky desertification (KRD) is defined as extreme soil erosion and reflects the risks of erosion. Thus, the relationship between T value and erosion risk is determined using KRD as a parameter. The existence of KRD land is unrelated to the T value, although this parameter indicates erosion sensitivity. Erosion risk is strongly dependent on the relationship between real soil loss (RL) and T value rather than on either erosion intensity or the T value itself. If RL > > T, then the erosion risk is high despite of a low RL. Conversely, if T > > RL, then the soil is safe although RL is high. Overall, these findings may clarify the heterogeneity of T value and its effect on erosion risk in a karst environment.


2021 ◽  
Vol 1047 ◽  
pp. 111-119
Author(s):  
Zhao Liu ◽  
Shu Sen Cheng ◽  
Liang Wang

A 300-metric ton converter in a steel plant in China was studied. The influence of factors such as slag composition and temperature in the smelting process on the dephosphorization effect was statistically analyzed. The dephosphorization ability of slag increased firstly and then decreased with the increase of temperature, basicity and FeO content. Low-temperature, high-basicity and high-oxidizing slag are thermodynamically beneficial to promote the dephosphorization reaction, but the basicity is higher than 4.0, and the temperature is higher than 1640 °C are not conducive to the slag to obtain better fluidity. At the same time, too high FeO content will increase the activity coefficient of P2O5, thereby increasing its activity, which is not conducive to the progress of the dephosphorization reaction. As the end point content of carbon decreases, the oxygen content increases and the phosphorus content decreases. A very low carbon content is not conducive to metal yield and temperature control.


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