scholarly journals A comparison between soil loss evaluation index and the C-factor of RUSLE: a case study in the Loess Plateau of China

2012 ◽  
Vol 16 (8) ◽  
pp. 2739-2748 ◽  
Author(s):  
W. W. Zhao ◽  
B. J. Fu ◽  
L. D. Chen
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Soil Loss ◽  
Drainage Network ◽  
Land Use Patterns ◽  
Low Area ◽  
Use Patterns ◽  
High Area ◽  
Land Use Types

Abstract. Land use and land cover are most important in quantifying soil erosion. Based on the C-factor of the popular soil erosion model, Revised Universal Soil Loss Equation (RUSLE) and a scale-pattern-process theory in landscape ecology, we proposed a multi-scale soil loss evaluation index (SL) to evaluate the effects of land use patterns on soil erosion. We examined the advantages and shortcomings of SL for small watershed (SLsw) by comparing to the C-factor used in RUSLE. We used the Yanhe watershed located on China's Loess Plateau as a case study to demonstrate the utilities of SLsw. The SLsw calculation involves the delineations of the drainage network and sub-watershed boundaries, the calculations of soil loss horizontal distance index, the soil loss vertical distance index, slope steepness, rainfall-runoff erosivity, soil erodibility, and cover and management practice. We used several extensions within the geographic information system (GIS), and AVSWAT2000 hydrological model to derive all the required GIS layers. We compared the SLsw with the C-factor to identify spatial patterns to understand the causes for the differences. The SLsw values for the Yanhe watershed are in the range of 0.15 to 0.45, and there are 593 sub-watersheds with SLsw values that are lower than the C-factor values (LOW) and 227 sub-watersheds with SLsw values higher than the C-factor values (HIGH). The HIGH area have greater rainfall-runoff erosivity than LOW area for all land use types. The cultivated land is located on the steeper slope or is closer to the drainage network in the horizontal direction in HIGH area in comparison to LOW area. The results imply that SLsw can be used to identify the effect of land use distribution on soil loss, whereas the C-factor has less power to do it. Both HIGH and LOW areas have similar soil erodibility values for all land use types. The average vertical distances of forest land and sparse forest land to the drainage network are shorter in LOW area than that in HIGH area. Other land use types have shorter average vertical distances in HIGH area than that LOW area. SLsw has advantages over C-factor in its ability to specify the subwatersheds that require the land use patterns optimization by adjusting the locations of land uses to minimize soil loss.

scholarly journals A comparison of the soil loss evaluation index and the RUSLE Model: a case study in the Loess Plateau of China

2012 ◽  
Vol 9 (2) ◽  
pp. 2409-2442 ◽  
Author(s):  
W. W. Zhao ◽  
B. J. Fu ◽  
L. D. Chen
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Soil Loss ◽  
Evaluation Index ◽  
Watershed Scale ◽  
Land Use Patterns ◽  
Land Use Pattern ◽  
Use Patterns ◽  
Use Pattern

Abstract. The development of new methods to examine the influence of land use on soil erosion is currently a popular research topic in contemporary research. The multiscale Soil Loss Evaluation Index is a new, simple soil erosion model that can be used to evaluate the relationship between land use and soil erosion; however, applications of this model have been limited, and a comparison with other soil erosion models is needed. In this study, we used the Yanhe watershed in China's Loess Plateau as a case study to calculate the Soil Loss Evaluation Index at the small watershed scale (SLsw), to identify the similarities and differences between results from the Soil Loss Evaluation Index and the Revised Universal Soil Loss Equation (RUSLE), and to determine the key location where land use patterns need to be optimized in the study area. The procedure for calculating the SLsw, namely, using the delineation of the drainage network and the sub-watersheds as starting points, includes the calculation of soil loss horizontal distance index, the soil loss vertical distance index, slope steepness factor, rainfall-runoff erosivity factor, soil erodibility factor, and cover and management practices factor. During the calculation procedure, several functions within geographic information system (GIS), especially the spatial analyst function, are used to calculate these factors layers, and many of the data are expressed in grid format. Moreover, The AVSWAT2000 hydrological model and upscaling methods were used to calculate some of the factors in this study. When comparing the SLsw with the RUSLE, some similarities and differences were discovered. The similarities of the two models include the following: (1) both use GIS techniques at the watershed scale, (2) the same factors appear in both models, (3) and the resolution of the basic data is closely related to the evaluation results. The differences between the SLsw and the RUSLE are as follows: (1) they have different outcomes, namely, the former analyzes the relationship between land use and soil erosion, and the latter analyzes the amount of soil erosion; (2) different grain scales are used in the two models, namely, the former uses the sub-watershed scale, and the latter uses the grid cell; and (3) the evaluation results are different, namely, the former is dimensionless but can identify the key area for land use pattern adjustment, and the latter provides the coarse soil loss rate but may have difficulty identifying the key area where the land use pattern urgently needs adjustment to control the soil loss because of the different soil erosion factors. On the basis of our results regarding the Soil Loss Evaluation Index in the Yanhe watershed and comparisons with the RUSLE, we conclude that the area with substantial soil erosion is primarily located in the middle and southeastern parts of the Yanhe watershed and is a composite effect from different soil erosion factors. Additionally, the sensitive area where land use patterns need to be optimized is primarily located in the middle part of the Yanhe watershed, covering 53.3% of the watershed. In future studies of land use pattern optimization, the calculation of the Soil Loss Evaluation Index at the slope scale may play a key role in identifying where land use patterns need to be adjusted in the sub-watersheds of sensitive areas.

scholarly journals The Hidden Characteristics of Land-Use Mix Indices: An Overview and Validity Analysis Based on the Land Use in Melbourne, Australia

2021 ◽  
Vol 13 (4) ◽  
pp. 1898
Author(s):  
Jiacheng Jiao ◽  
John Rollo ◽  
Baibai Fu
Keyword(s):  
Land Use ◽  
Screening Method ◽  
Comparative Trial ◽  
Dissimilarity Index ◽  
City Center ◽  
Land Use Patterns ◽  
Use Patterns ◽  
Land Use Types ◽  
Land Use Mix

The land-use mix index is a way to quantify the mixture of land-use patterns. Due to practical limitations, few studies have highlighted the validity of land-use mix indices. This paper aims to explore the potential characteristics of land-use mix indices using a three-step screening method. The data precision of indices was concluded after the first-step screening. A total of 10 virtual blocks and 217 blocks in Melbourne city center served as a case study and reflected the various land-use structures. The randomized controlled comparative trial was incorporated into the second- and third-screening to indicate the applicable condition and validity. The results illustrate that the value Herfindahl–Hirschman index related to the diversity of land-use types. The results also confirmed that Dissimilarity index-I was significantly associated with the balance status of the land-use mix. Entropy index reflects the evenness but did not correlate to the diversity or balance of the land-use mix. In addition, the study also provides a set of general recommendations for the application conditions of land-use mix indices.

The magnitude of soil erosion of small catchments with different land use patterns under an extreme rainstorm on the Northern Loess Plateau, China

2020 ◽  
Author(s):  
Nan Wang ◽  
Juying Jiao
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Loess Plateau ◽  
Stepwise Regression ◽  
Digital Terrain Model ◽  
Shaanxi Province ◽  
Land Use Patterns ◽  
Use Patterns ◽  
Land Use Types ◽  
Erosion Intensity

<p>The characteristics of soil erosion under extreme rainstorm conditions can reflect the effect of ecological restoration measures and the rationality of land use patterns in the region. 12 dam-controlled catchments was selected after an extreme rainstorm event occurred in the northern Shaanxi Province on 25-26 July 2017 (called “7.26” rainstorm). Soil erosion intensity in the 12 catchments was obtained by digging up the sedimentation profiles and measuring the sedimentation areas. Using digital orthophoto map and digital terrain model by Unmanned Aerial Vehicle to obtain land-use types and their areas, slope gradients and the distance along the flow path to the edge of the downslope and dam-land. Stepwise regression method was used to analyze the main factors affecting catchment erosion intensity. The results showed that the average sedimentation thickness in the 12 damlands ranged from 0.16 m to 1.67 m and the intensity of soil erosion of the 12 catchments varied from 10295 t km<sup>-2</sup> to 49227 t km<sup>-2</sup>. Soil erosion caused by this rainstorm was 10-50 times of the allowable amount of soil erosion in the Loess Plateau region (1000 t km<sup>-2</sup>.a) issued by Ministry of Water Resource of the People’s Republic of China (MWR). Stepwise regression analysis shows that, the closer the shape of a catchment to the circle is, the larger the area of slope-cropland in inter-gully land is or the closer the distance between slope-cropland and the dam-land is, the larger the erosion modulus in the catchment would be. What’s more, the presence of cement road up the valleys shoulder line reduced the modulus of soil erosion. Theses findings indicated that the existing ecological conditions in the dam-controlled catchments are not able to resist extreme rainstorm erosion effectively. Optimizing the distribution of land use types in catchments should be the focus of soil erosion control.</p>

scholarly journals Variation in the Continuity of Land-Use Patterns through the First Millennium AD in Lowland Britain

2015 ◽  
Vol 11 (1) ◽  
pp. 135-154
Author(s):  
Stephen Rippon ◽  
Ralph Fyfe
Keyword(s):  
Land Use ◽  
Roman Empire ◽  
Causal Effect ◽  
Anglo Saxon ◽  
Land Use Patterns ◽  
Profound Change ◽  
Use Patterns ◽  
Land Use Types ◽  
First Millennium

AbstractThis paper explores the contribution that palaeoenvironmental evidence, and in particular palynology, is making to our understanding of landscape evolution in Britain during the 1st millenniumAD. This was a period of profound social and economic change including a series of invasions, some associated with a mass folk migration. Archaeologists and historians continue to debate the significance of these events, and palaeoenvironmental evidence is now starting to provide an additional perspective. Key to this has been obtaining pollen sequences, although there remains a need for more evidence from lowland areas, alongside higher resolution sampling and improved dating. It is suggested that although the 1st millenniumADsaw some significant long-term shifts in climate, these are unlikely to have had a significant causal effect on landscape change in lowland areas (both in areas with and without significant Anglo-Saxon immigration). The analysis of pollen data from across Britain shows very marked regional variations in the major land-use types (arable, woodland, improved pasture, and unimproved pasture) throughout the Roman and Early Medieval periods. While Britain ceasing to be part of the Roman empire appears to have led to a decline in the intensity of agriculture, it was the ‘long 8th c.’ (the later 7th to early 9th c.) that saw a more profound change, with a period of investment, innovation, and intensification, including an expansion in arable cultivation.

Distribution of heavy metals in topsoils affected by land use patterns at a small watershed scale: a case study in the Bantou Reservoir watershed in Xiamen, China

2015 ◽  
Vol 35 (16) ◽  
Author(s):  
李清良 LI Qingliang ◽  
吴倩 WU Qian ◽  
高进波 GAO Jinbo ◽  
马军 MA Jun ◽  
徐秋芳 XU Qiufang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Land Use ◽  
Watershed Scale ◽  
Small Watershed ◽  
Land Use Patterns ◽  
Use Patterns ◽  
Reservoir Watershed
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