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《Resources Science》 2010-03
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Seasonal Changes in Desalination Mechanisms and Economic Benefit Analysis on the 'Raised Field-Shallow Pond' in Saline-Alkali Regions around the Bohai Sea

ZHANG Hua1,2,ZHANG Yue1,YUE Yaojie1,2,3,LI Ya1,LIN Yao1,SHENG Zhongyao1,WANG Jingai1,2,3 (1. School of Geography and Remote Sensing Science, Beijing Normal University,Beijing 100875,China; 2. Key Laboratory of Regional Geography, Beijing Normal University, Beijing 100875,China; 3. State key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China)  
There are 30 million hectares of saline-alkali soil land in China, accounting for 7% of the total state-owned arable land. Fresh water resources are extremely scarce around the Bohai Sea coastal areas. In addition, droughts, waterlogging, salinity and groundwater mineralization frequently happen over the areas. As a result, agricultural productions for this region are extremely instable in general. In the present work, the land use pattern of the 'raised field-shallow pond' model for agricultural lands in Dongying City, Shandong Province, and heavily saline-alkali land in Huanghua County, Hebei Province were investigated by incorporating field experiments with questionnaire survey. The desalination efficiency and production improvement benefits in the two study sites were compared and analyzed in detail. Results showed that climatic factors often leaded to a significant variation in surface salt in salty wastelands during periods of seasonal changes, which greatly affected the crop growth and development. More salinity in topsoil was accumulated during a short period of hot weather in summer. If precipitation amount was relatively large, surface runoff would result in serious losses of heavily sticky soil due to its poor permeability, which was however contrary to the full desalinization efficiency of salt. It was found that the 'raised field-shallow pond' model can reduce or restrain water and soil loses to some degree, thereby indicating an important role in dramatic salt reductions and in alleviating or eliminating acuity salt accumulation during periods of seasonal rain and heat changes. The desalinization efficiency of the furrow layer in the 'raised field -shallow pond' model was estimated to be roughly 58.8% and the average desalination efficiency of the sandy soil furrow layer of the 'raised field-shallow pond' in Dongying City was about 79.7%. The cotton yield was 4500 kg per hectare; it was increased by 50% compared with the traditional farming mode. The input-output ratio was about 1:3.75. It was also found that the average desalination efficiency of the clay soil furrow layer of the 'raised field-shallow pond in Huanghua County was 37.9%, with showing a cotton yield of 3000 kg per hectare and an input-output ratio of 1:2.5. The 'raised field-shallow pond' plays a prominent role in desalination, salt-stability and water resources regulation and storage during periods of seasonal rain and heat changes. It can also be a field for farming and fishing, providing farmers with productive lands and fishing ponds as well as regulating salt content in infertility lands. This study would offer meaningful reference for soil transformation for heavily saline-alkali lands, grain production improvement, land utilization and eco-economic development around the Bohai Sea coastal areas.
【Fund】: 国家863重点计划项目(编号:2006AA100206)
【CateGory Index】: S156.4
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