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In this study, a total of 84 sites in the Luan River Basin of China and its tributaries were monitored in 2012 for seven heavy metals (Cu, Ni, Pb, Zn, Cd, Cr, Hg) in the surface sediments. Cluster analysis (CA), principal component analysis (PCA), correlation analysis, and pollution indices were applied to the interpretation of the monitoring results. The results show that: (1) sampling sites in the mainstream are classified into two groups, upstream and downstream, with downstream representing higher levels of heavy metals and degrees of pollution; (2) three clusters were identified for the 10 tributaries, the downstream having the highest levels of heavy metals’ pollution; (3) the PCA suggests there are significant correlations among Zn, Cu, and Pb between Cr in the basin. Sediment pollution assessment was carried out using Pollution Index (PI) and Geo-Accumulation Index (Igeo). Mercury was the metal with the highest contamination level, followed by Cd and Cr. The results provide an overview of the current status of sediment contamination with measured data and support future policy development for the protection of water quality in the Luan River Basin. [ABSTRACT FROM AUTHOR]

Abstract: The Soil Conservation Service Curve Number (SCS-CN) method is widely used for predicting direct runoff from rainfall. The ratio of initial abstraction (Ia) to maximum potential retention (S) was assumed in its original development to be equal to 0.2 in SCS-CN method. The constant initial abstraction ratio is the most ambiguous assumption and requires considerable refinement. The objectives of this study were (1) to determine the initial abstraction ratio, in an experimental watershed in the Three Gorges Area of China, by analyzing measured rainfall-runoff events; (2) to compare the performance of the traditional and modified Ia/S values with observed rainfall-runoff data. The dataset consisted of 6 years of rainfall and runoff measurements from the experimental watershed. The results indicated that the Ia/S values, using event rainfall-runoff data, varied from 0.010 to 0.154, with a median of 0.048. The average initial abstraction ratio of the watershed was equal to 0.053. The standard SCS-CN method underestimates large runoff events, yielded a slope of the regression line of 0.559 and an intercept of 0.301. The modified Ia/S value was about 0.05 that better predicted runoff depths with an R 2 of 0.804 and a linear regression slope of 0.834. It also improved model efficiency coefficient (E) to 0.768 compared with 0.482 for traditional Ia/S value. This Ia/S-adjusted SCS-CN method appears to be better appropriate for runoff prediction in the Three Gorges Area of China. [Copyright &y& Elsevier]

Abstract: Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus (P) loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme (PRS) was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as “low”, “medium” or “high” potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS. [Copyright &y& Elsevier]

Abstract: Sustainability has become an important discussion topic across the world since the late 1980s. However, there is still lack of knowledge about the landscape sustainability and its quantitative evaluation, especially at local and regional scale levels. The sustainable development of the Chinese Loess Plateau has always been a focus in China mainly because of the occurring severe soil erosion. This study investigates the changes of the landscape pattern and the changes of the ecological sustainability of the agricultural landscapes in Ansai County between 1980 and 2000, which is located in the northern part of the Chinese Loess Plateau. Using a landscape typology as a spatial reference framework, the concept of hemeroby was used, in a multidisciplinary approach, for the assessment of the ecological aspect of agricultural landscape sustainability. We combined expert judgement with a regression model and a Geographic Information System. Fourteen variables describing the landscape structure were chosen as predictors for hemeroby. The research showed that the major changes in the agricultural landscape pattern were caused not only by socio-economic factors but also by the government policies over the past two decades, such as the large-scale eco-environment conservation programmes starting in the late of the 20th century. One of these programmes is known as the Grain-for-Green Programme (initiated in 1999). Between 1980 and 2000, the proportion of cropland-dominated landscape sharply decreased while the percentage of the mixed farmland–grassland landscape and the mixed farmland–woodland–grassland landscape increased. Meanwhile, the ecological sustainability of the agricultural landscape as a whole tended to become more sustainable, except a few landscape types. Among variables describing landscape pattern, patch size standard deviation (PSSD), total edge (TE), mean shape index (MSI), landscape shape index (LSI) and Shannon''s evenness index (SEI) were shown to be the significant predicators for hemeroby. Although some data limitation, landscape structure turned out to be a good predicator for land use intensity and ecological sustainability of agricultural landscape estimated by hemeroby. As a highly integrative indicator, the concept of hemeroby provides a framework for the comparison of different land use pattern. [Copyright &y& Elsevier]

Abstract: We sought to detect the temporal change (1958–1999) in land use patterns and its relationship to physical landscape parameters in a small catchment in the semi-arid hilly area of the Chinese Loess Plateau. Degree of slope and soil type were selected as stable discriminating parameters that might constrain land use. With the help of GIS and canonical correspondence analysis, the relationship between rural land use distribution or transformation and the selected physical parameters was examined. The land use had undergone a general shift from farmland to woodland or grassland. Canonical correspondence analyses (CCA) indicated that a relationship between land use and the selected physical parameters was evident, farmland coincided with favorable conditions of fertile soil and gentle slope, while grassland and woodland were associated with conditions of poorer soil and steep slope. In the more favorable conditions the main land use change process was the intensification of farming, while in the less favourable conditions it was the abandonment of farmland. A thorough understanding of the relationship between land use temporal or spatial patterns and landscape physical parameters in the Loess Plateau of China, like degree of slope and soil type, will enhance our capability to predict landscape dynamics and lead to more sound and effective land use management strategies. [Copyright &y& Elsevier]

Poor vegetation cover as a result of irrational land use is generally considered to be the major factor of soil erosion in the Loess Plateau in China. However, there is lack of knowledge concerning the dynamics of land use and the complex role of socio-economic policy factors in inducing changes in land use, especially at detailed scale levels such as in individual small catchments. This study analyzes the process of human-induced landscape change in a small catchment in the northern part of the Chinese Loess Plateau from 1958 to 1999. During this period, a significant reduction of the area of farmland on steeper slopes and an increase in woodland took place. Household questionnaires among the local farmers, a review of the historic events and literature allowed the assessment of socio-economic and policy forces that caused these changes. The research showed that the changes of agricultural landscape pattern are mainly the result of the dissolution of People’s Communes in 1979 (established in 1956), the introduction of a Household Responsibility System (in 1978), the implementation of the Family Planning policy (in 1978), and the adoption of a market-directed economic system (in 1992), as well as the execution of an integrated soil erosion control project (begun in 1981). The changes of the agricultural landscape show the benefits in both ecological and economic respects. [Copyright &y& Elsevier]

Presents a study which examined the effects of land use and its patterns on soil moisture and nutrients in the hilly area of Loess Plateau in China. Description of the study area; Comparisons of soil moisture among land uses for wet and dry years; Effects of landscape position on soil nutrients.

Presents a study which compared the soil qualities of different land uses in Wolong Nature Reserve, Sichuan Province, China using the integrated soil quality index and soil deterioration index. Description of the study area; Soil sampling methods and processing; Calculation of soil deterioration indices; Effects of different land uses on soil properties after deforestation.

Abstract: The spatial variation of soil nutrients in topsoil (0-20cm) was analyzed using semivariogram in the Zunhua County of Hebei Province, China. The effect on semivariogram with randomly deleted data and kriged estimates using various reduced sample sizes was also analyzed. The semivariograms of available N, total N, available P, organic matter were best described by a spherical model, except for available K, which best fitted a complex structure of exponential model and linear with sill model. The ratio of nugget to total sample variance ranged from 34.4% to 68.4%, indicating the spatial correlation of tested soil nutrients on a large scale was moderately dependent. Among five soil nutrients, available nitrogen and available phosphorus had the shortest spatial correlation range (5 km and 5.5 km), available K had the longest range (25.5 km), whereas total nitrogen and organic matter had intermediate spatial correlation range (14.5 km and 8.5 km). The semivariograms of available N, total N, available P, and organic matter were insensitive to a 50%-60% reduction in original sampling density, while for available K, it is up to 70%. The estimated spatial distributions of total N by kriging, under various reduced sample sizes, all correlated significantly (P = 0.001) with those obtained from original data. The results showed that the semivariogram was a relatively robust tool when used in a large region and sufficient spatial variation information could be retained regardless of a higher deletion proportion of the original data. The original sample data could be reduced by kriging and the estimates showed no loss of spatial information, however, the results may be unreliable unless a clearly identified semivariogram model could be obtained. The results may provide useful information for determining the appropriate sampling densities for these scales of soil survey. [ABSTRACT FROM AUTHOR]