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Relationship between soil physiochemistry and
land degradation in the lower Heihe River basin of northwestern China |
Qi FENG1,Haiyang XI1,Wei LIU2, |
1.Cold and Arid Regions
Environmental and Engineering Research Institute, Chinese Academy
of Sciences, Lanzhou 730000, China; 2.State key Laboratory
of Hydrosciences and Engineering, Tsinghua University, Beijing 100084,
China; |
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Abstract Monitoring of soil-water physiochemistry (pH, total salt content, ion types, and ion ratios) across the lower Heihe River basin of northwestern China indicated that the distribution of different soil hydrochemical types typically correlated with that of different levels of soil desertification, specifically: 1) lands with the potential for desertification showed a soil-water ion complement, 2) those under on-going desertification a ion complement, 3) those under severe desertification a ion complement, and 4) those under very severe desertification a ion complement. The total soil N, P, and K, pH and organic matter of desertified lands tend to be relatively spatially concentrated, whereas available N, P and K are scattered. Based on an analysis of the main nutrients, the cumulative percent contribution of total N, total P, organic matter, and available N reached 76.24% of ecosystem needs and basically reflect the level of soil fertility. According to a low-dimensional cluster analysis of principal components and the differentiation and alikeness of integrated nutrient gradients, the soils in the study region were classified into four types, which coincided spatially with the four desertification land types. With a decrease in the quantity of water exiting the upper and middle reaches of the Heihe River basin, the salinity of surface waters and shallow water table depth (WTD) in the lower reaches have significantly increased through evaporation. The changes in the hydrological process have caused an imbalance in water distribution across the basin, and altered the state of oasis-supporting water resources. The deterioration of soil water and expansion of desertification progress from non-salinized soils in the oasis, to soils slightly salinized through periodic salt accumulation, salinized Chao soils, and salinized forest shrub meadow soils along the riverbanks and on lake shores. These can then evolve into moderately to heavily salinized soils and eventually into alkali lands. All together, these degradative processes constitute the complex dynamics of oasis desertification, whereby the natural oases’ surface biotic productivity system is degraded, leading to oasis shrinkage, ecosystem deterioration, and land desertification. Consequently, there is an urgent need to extend the study of soil and surface water chemistry in the region.
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Keywords
lower Heihe River
soil salinity
land degradation
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Issue Date: 05 December 2009
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Bao S D(2005). Analysis of soil agronomic chemistry (third edition). Beijing: Chinese Agriculture Press, 495 (in Chinese)
|
|
Feng Q, Endo K H, Cheng G D(2002). Soil water and chemical characteristicsof sandy soils and their significance to land reclamation. Journal of Arid Environments, 51: 35―54
doi: 10.1007/s00254-003-0950-7
|
|
He W S(2004). Temporal and spatial variability of soil nutrients inplough layer of farmland soils in Ningxia province. Chinese Journal of Soil Science, 35(6): 170―174 (in Chinesewith English Abstract)
|
|
Lei Z D, Yang S X, Xie S C(1984). Analysis of diving stable evaporationand experience formula. Journal of HydraulicEngineering, 60―64
|
|
Lei Z D, Yang S X, Xie S C(1988). Dynamics of soil water. Beijing: Tsinghua University Press, 141―146 (in Chinese)
|
|
Liu W, Wang T, Su Y H, Feng Q(2005). Analysis of the characteristics of soil and groundwater salinityin the lower reaches of Heihe River. Journalof Glaciology and Geocryology, 27(6): 890―899 (in Chinese with English Abstract)
|
|
Liu M, Gan Z M(2004). Influenceof water resources development on Ejin oasis in Heihe river basinand countermeasures. Journal of DesertResearch, 24(2):162―166 (in Chinese with English Abstract)
|
|
Lou F L, et al (1964). The relationship between soil accumulatingsalt and groundwater. Journal of HydraulicEngineering, (3): 1―11
|
|
Mao X M, Li M, Shen Y L(1998). Analysis of the phreatic evaporationin yarkant river basin, Xingjian. AridLand Geography, 21(3): 44―50 (in Chinese with English Abstract)
|
|
Su Y H, Feng Q, Liu W, Shi J H(2004). The degradation of ecological environment in Ejin and its cause analysis. Plateau Meteorology , 23(2): 264―270 (in Chinesewith English Abstract)
|
|
Team of soil system classification instituteof soil Nanjing, CAS (1991). Item of soil laboratory analysis and methods codes (soil system classificationin china), 68―71 (in Chinese)
|
|
www.tps.com.au/
|
|
Yan L, Hu Y C, Dong Z(2000). Primary study of soil salinity characterin Ejin oasis. Journal of Arid Land Resourcesand Environment, 14 (Suppl): 25―30
|
|
Zhang X Y, Gong J D, Zhou M X(2004). Analysis on Characters of Soil Salinityin Ejin Delta. Journal of Desert Research, 24(4): 442―447 (in Chinese with English Abstract)
|
|
Zhang Z X(2002). Matlab procedure design and application. Beijing: Tsinghua University Press, 11 (in Chinese)
|
|
Zhou L(1988). Research on growth of Eremophila alpestris nestlingII-main principle analysis of measuring indices of Eremophila alpestrisnestling growing. Colloquium of internationallearning conference about high altitude and cold meadow ecologicalsystem (C), 10
|
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