不同类型土壤N、K的转化特征

Transformation characters of nitrogen and potassium of different soils

土壤硝化力主要受土壤ｐＨ值制约，红壤硝化力最强，冲积土次之，滨海盐土最弱．土壤对ＮＨ＋４和Ｋ＋的固定，主要决定于粘粒矿物的类型和含量．红壤固定容量小，保肥稳肥能力弱，Ｎ素损失量高；冲积土和滨海盐土固定容量大，保肥稳肥能力强，Ｎ素损失少．提高供Ｋ水平，将会促进Ｎ素释放，抑制铵固定．而提高土壤Ｎ素水平，由于Ｎ素转化的复杂性。

Soil nitrification was dominated by soil pH, the nitrification of red earth was the strongest among 3 soils, the second was alluvial soil, and the nitrification of marine soil was the weakest. Fixation of NH + 4 and K + in the soil was determined by the contents and types of clay minerals. The red earth possesed low capacity of K + and NH + 4 fixation, and low N K holding capability, Thus the loss of nitrogen was high. Contrary, alluvial soil and marine soil possesed high capacity of K + and NH + 4 fixation, and high N K holding capability, the loss of nitrogen was low. Increasing K supply would promote nitrogen release and suppress NH + 4 fixation. But rasing N supply had no effect on release and fixation of K + due to the complicated transformation of nitrogen.