东北地区主要旱地土壤供硅状况及土壤硅素形态变化的研究

东北地区主要旱地土壤有效硅（SiO2，下同）含量为黑土、褐土较高，草甸土、棕壤居中，白浆土最少;有效硅平均含量分别为605.1、577.5、357.0、271.3、149.2mg／kg土壤有效硅含量与土壤的pH及粘粒含量呈极显著和显著正相关。在一定水分条件下，施入土壤中的硅在0～30天内主要以植物可利用的水溶态或硅胶形态存在，在0～20天内土壤有效硅含量变化不大，20～30天趋于减少。土壤各种形态硅含量为无定形硅＞活性硅＞水溶性硅。有效硅含量与活性硅的相关关系达极显著水平（r=0.8438* *，n=16），与无定形硅及水溶性硅无明显相关。

STUDY ON SUPPLYING CAPACITY AND CHANGING FORMS OF SILICON IN UPLAND SOIL OF NORTHEAST CHINA

The state of available Silicon content of main soils in northeast region was studied.The result showed that the available Si content of black soil and cinnamon soil are high, meadow soil and brown earth are medium and the least is alabic soil. The average content of each soil is 605. 1, 577. 5, 357. 0. 271. 3 and 149. 2mg/kg respectively. There is a significant positive correlation between available sillcon content and pH value and also clay content of soil.Under certain soil water condition, the silicon is in available form (soluble or active) absorbed by plant after silicon was applied within 30 days. The change of the content of available silicon is rare within 20 days and tend to decrease during 20～30 days after Si was applied. The content range of different forms of silicon is undefinite form of silicon>active silicon>soiuble silicon. There is a significant positive correlation between available silicon content and active silicon content (r=0. 8438^{* *}, n= 16). and no correlataion between available silicon and undefinite form of silicon or soluble silcon.