The Basic Study On The Salt Water’s Application In Coastal Saline Soil Salt Leaching

Saline soil, a kind of widespread distribution and an important soil resource, which is in the proportion of25%to the land total area, amounts to approximately10hundreds million ha. In the world, saline soil is mainly concentrates in Eurasia, West Africa and North America. In our country, the total area of saline soil is about34.6million ha. The mainly distributing regions are northeast, North China, northwest interior area and seaboard being north of Yangtze River. Now, the improvements of saline soil have been a cosmopolitan problem.As our country has a large area of saline, but also is rich in salt water, the paper chose the saline soil of the North Sea Area of Tianjin with indoor simulation experiments to study the best Salt Water’s Application in Saline Soil Improvement. The results as follows:(1) By leaching small soil column simulation experiments with salt water, the infiltration characteristics and desalination principle of a sandy loam coastal saline soil, and water saving potential with salt water were studied. The results indicated that, the salt water had a light negative effect on soil infiltration characteristics, but infiltration ability no longer decreased when mineralization degree of salt water was above15.61g/L. The water-saving potential of leaching saline soils with salt water was great, and the water-saving rate with salt water of5.35g/L,10.36g/L and sea water was48.08%,38.46%and24.04%, respectively.(2) Continue to leach the small soil column simulation after salt water, to study the actual water savings of different salinity water and it was different from estimated potential value of salt water. All the e actual water savings of different salinity water s in the control group of freshwater rates were:18%,16%,9%,8%and5%, which is about50%of the water-saving potential of the corresponding salt water. Then study the curve of salinity changes in lucent and to measure the soil salt ions after salt water leached, the result showed that although Soil total salt content downed to a relatively low level, some of the ion content is still high, especially Cl-and Na+,its affected desalination efficiency of fresh water, and caused salt water saving estimated potential value significantly greater than the actual amount of water-saving.(3)According to small columns research,I choose salt water of5.35g/L,10.36g/L to study on the big soil columns,which were leached with salt water and fresh water to study dynamic law of salt water movement of coastal salinized soil and the effect of desalting. The result was as follows:the change of effluent’ mineralization degree were both in coincidence with "W" when the fresh water or salt water leached the soil columns, the fresh water continued leaching the soil columns after the salt water have done with them, when the effluent’ mineralization degree was slow to subside. The soil columns were taken soil in every layer and SAR、RSC、pH were measured, the results indicated that the soil became alkaline after the salt water and fresh water leached by turns.