Eco-geological environment quality assessment based on multi-source data of the mining city in red soil hilly region, China

High-intensity and large-scale resource development seriously threatens the fragile ecological environment in the red soil hilly region in southern China. This paper analyzes the eco-geological environmental problems and factors affecting Ganzhou, a mining city in the red soil hilly region,based on field survey and literature. The ecogeological environment quality(EGEQ) assessment system, which covered 11 indicators in physical geography, mining development, geological hazards,as well as water and soil pollution, was established through multi-source data utilization such as remote sensing images, DEM(Digital Elevation Model), field survey and on-site monitoring data. The comprehensive weight of each indicator was calculated through the Analytic Hierarchy Process(AHP) and entropy method. The eco-geological environment assessment map was developed by calculating the EGEQ value through the linear weighted method. The assessment results show that the EGEQ was classified into I-V grades from excellent to worse, among which, EGEQ of I-II accounted for 29.88%, EGEQ of III accounted for 32.35% and EGEQ of IV-V accounted for 37.77%;the overall EGEQ of Ganzhou was moderate. The assessment system utilized in this research provides scientific and accurate results, which in turn enable the proposal of some tangible protection suggestions.

Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions,China

Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studied. Fixed observation results from 1993to 2002 showed that pools covering about 15% of total area could store up 10% of surfacerunoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio ofinterception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in thecatchment area system, and benefited the aquatic culture and helped to resist seasonaldrought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 tkm-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddyfield increased steadily (>10%); water storage enhanced by more than 20% in sloping landand dryland in drought season; crop production increased by more than 20%; and productionof trees, fruits, tea and fish as well as land productivity increased yearly.

Assessing effects of land use and land cover changes on hydrological processes and sediment yield in the Xunwu River watershed, Jiangxi Province, China

The effects of land use and land cover changes on hydrological processes and sediment yield are important issues in regional hydrology.The Xunwu River catchment located in the red soil hilly region of southern China has experienced drastic land use changes in the past 30 years,with orchard increases of approximately 42%and forest decreases of approximately 40%.These changes have resulted in some alterations of runoff and sediment yield.This study aims to evaluate effects of land use/land cover on runoff and sediment yield in the Xunwu River catchment.The SWAT model(Soil and Water Assessment Tool)was used for runoff and sediment simulation,and the results met the requirements of the model acceptance based on evaluation statistics of R^(2)(the coefficient of determination),PBIAS(percent bias),and NSE(Nash-Sutcliffe efficiency).Four land use scenarios representing the gradual expansion of orchards in the past 26 years were developed for assessment of hydrological processes and sediment yield simulation.As a result,both runoff and sediment yield were changed insignificantly with decrease rates of 1.84%and 5.29%,respectively.In addition,surface runoff accounts for the largest share of the runoff components,but the lateral flow changed more than other runoff components with a decrease rate of 10.96%.The results show that orchard expansion does not reveal severe water and soil loss.This study can contribute to the rational utilization of land and water resources in the red soil hilly area of southern Jiangxi Province.