Soil Salinization in Lower Haihe Plain, China Salinisation Des Sols Dans La Plaine Alluvio-Marine De Haihe, Chine
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Scientific registration no: 2140 Symposium no: 29 Presentation: poster Soil Salinization in Lower Haihe Plain, China Salinisation des sols dans la plaine alluvio-marine de Haihe, Chine MAO Renzhao (1), MATSUMOTO Satoshi (2), FITZPATRICK Rob W. (3) (1) The CAS Shijiazhuang Institute of Agricultural Modernization, 050021, China (2) The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113, Japan (3) CSIRO Land and Water, P.B.No. 2, Glen Osmond, SA 5064, Australia Lower Haihe plain, being about 5,000,000 hm2, includes sea deposit plain and lower part of alluvial plain, which locates in Hebei province and Tianjin district. It is one of main saline soil and severely potential salinization threat region in North China. The saline soil, 850,000 hm2 at present, will still become one of limited factors for sustainable agriculture. Under being controlled by semi-dry monsoonal climate, annual vaporisation (from water surface) content is 3-4 times of precipitation, but even it reaches 6-10 times in spring (from March to May). Salt leaching process occurs in only rain season of 2 months long, and salt of upper soil temporarily comes down and stops in middle and bottom of -1 profiles. There are two kinds of saline soil based on Cl/0.5•SO4 (cmol·kg ) rate. Chloride soil develops in the region about 40-50 km wide paralleled with the Sea Bo coast. Sulphate soil occurs in inner land adjacent to former one. In its major part the mineralised salt content is common between 3-5 kg/m3, some up to 10 kg/m3, a few over 30 kg/m3 in coastal area. So original groundwater is a main salt source of soil. The descent of groundwater table has a positive role for to reduce salinization. With introducing water from Yellow river into Cangzhou, an extreme water-deficient area, a biggest reservoir of plain had already be constructed. Undoubtedly this activity can lead to some soil environment problems, especially soil salinization. So in order to firm the achievement of saline soil amelioration and prevent from secondary salinization, it is necessary for to do as follow: 1. Government should strengthen defence, reconstruction and management of the available drainage projects; 2. Irrigation and drainage system are coordinated ; 3. Some advanced techniques should extend, for example, slightly salty even salty shallow-water use for reasonable season and crops in lack of fresh water region; 4. Scientific research departments and local organisation should establish continuous monitoring system for soil and groundwater, and put forward feasible program to help farmer in close surrounding of the reservoir; 5. Any time it will be important to take comprehensive measures and suit local condition. Key words: salinization, Haihe plain, Chine Mots clés : salinisation, plaine de Haihe, Chine.