Researches on Application of Gypsum for the Improvement of Soda Saline and Alkaline Soil

The method of field locational experiment was used to conduct the researches of the improving actions of gypsum on soda saline and alkaline soil.The results showed that the application of gypsum increased the standing number of seedlings and the growth of maize.Af-ter the application of gypsum,the soil pH values were significantly decreased,the hardness of field soil was universally decreased the three phases proportion of maize field were generally improved,the dry weight of roots was significantly increased,Ca 2+ and Mg 2+ were increased,K + and Na + were decreased and ESP were universally decreased,the soil chemical properties were significantly improved.The determination of yield in autumn showed that maize yield per unit area was increased by12.58%～44.31%.Furthermore at the second year and the third year af-ter gypsum was applied,the later effects of gypsum were still very significant,gypsum still had the most significant yield increase effects on sorghum and sunflower.