黄土区土壤钾的形态及其释放

本文研究了黄土区（陕西部分）土壤钾的形态，按毫克/100克土计，有机钾0.36-5.04，水溶性钾0.24-2.37，代换性钾3.61-16.96，有效钾3.85-19.33，非代换性钾64.45-149.77，结构钾1，840.3-2.538.3，全钾为1.920-2.640。有效钾为非代换性钾的11.42%，结构钾的0.53%和全钾的0.51%。水溶性钾和代换性钾分别是有效钾的8.2%和91.8%。通过主成分分析可知，土壤各种形态的钾与有机质呈正相关:水溶性钾、代换性钾、非代换性钾与有机态钾，代换性钾和非代换性钾与粉粒和粘粒也呈正相关，但都与沙粒呈负相关.钾的释放符合于幂回归方程（y=ax^-b）.释放量从北向南是逐渐增加的.幼年土壤和轻黑垆土耕作层释放量高于其他层次，但是粘黑垆土和黑土的粘化层的释放量高于其它层次。

THE FORMS AND RELEASE OF POTASSIUM IN SOILS OF THE LOESS REGION

Distribution of forms of potassium was studied in the cultivative soils of loess region (Shaanxi province). The content of organic, water soluble, exchangeable, available, nonexchangeable, lattice and total K range 0.36-5.04, 0.24-2.37, 3.16-16.62,3.85-18.99, 64.45-149.77,1840.34-2538.30, 1920.00-2640.00mg/100g soil respectively. The available K constitute 11.42% of nonexchangeable K,0.53% of lattice K and 0.15% of total K. The water soluble and exchangeable K are 8.2% and 91.8% of available K respectively. All the potasslum forms were positively correlated with organic matter, also, exchangeable and nonexchangeable K with silt and clay, exchangeable K with nonexchangable K,exchangeble and nonexchangeable K with organic K. But organic, watersotuble, exchangeable, nonexchangeable, lattice and total K are negative correlation with sand. The process of potassium releasse accord with power equation(y=ax^-b). Content of potassium releasse gradually increased from north to south in loess region. Cultivated horizon of young soils (yellow cultivated loessial soil, irrigating warped soil) and dark Herlu soil are higher than other horizon in potassium release content. But clay-rich horizou of dark Heilu soil gnd dark Lou soil are higher than other horizon.