摘要
选用浙江省杭州地区的青紫泥田、泥质田和粉泥田等三种具代表性的水稻土作供试土样,研究了钾容量强度比(K-Q/I)和铵容量强度比(NH_4-Q/I)的相互关系及K^+对NH_4-Q/I或NH_4^+对K-Q/I的影响.结果表明:三种土壤对K^+的亲和力远比对NH_4^+的亲和力强.K^+对NH_4^-Q/I或NH_4^+对K-Q/I的影响,受(Ca+Mg)_(ex)降低、专性吸附NH_4^+-K^+比改变和陪补离子等综合作用.前两种使AR^(NH_4)或AR^K趋向提高.陪补离子的作用,青紫泥田和泥质田中,K^+使AR^(NH_4)趋向提高,而粉泥田相反.三种土壤中NH_4^+使AR^K趋向下降.三种土壤都因加K^+而提高AR^(NH_4)值,但粉泥田主要发生在低AR^(NH_4)值,受专性吸附影响,其它作用影响较小.加NH_4^+使青紫泥AR^K提高、泥质田AR^K降低、粉泥田在低AR^K时提高而高AR^K时降低;NH_4^+使AR^K提高主要由专性吸附引起,使AR^K下降是由陪补离子的影响超过其它两种总影响引起.
Three representative paddy soils in Hangzhou area of Zhejiang Province were collected to study the relationships between K-Q/I and NH4-Q/I,and the effect of K+ on NH4-Q/I and NH4 + on K-Q/I curve was discussed. Experimental results showed that the affinity of the soils was much higher for K+ than for NH4 + . The effect of K+ on NH4-Q/I curve or NH4+ on K-Q/I curve was essentially a comprehensive balance of the decrease in (Ca+Mg)ex,the change in the ratio of NH4+/K+ specifically sorbed on the exchanger and the complementary ion effect. The first two factors tended to increase ARNH4 or ARk and the complementary ion effect was more complicated. For instance,K+ increased ARNH4 in the blue clayey paddy soil and fluviogenic loamy paddy soil but decreased it in the silt loamy paddy soil. As far as the three soils are concerned, the addition of NHf4+ decreased ARk value whereas the addition of K+ increased ARNH4 value,except that increase in ARNH4 occurred only at low range of ARNH4 .suggesting the dominant influence of the specific adsorption of K+. The addition of NH4+ increased ARk for the blue clayey paddy soil but decreased ARk for the fluviogenic loamy paddy soil,and for the silt loamy paddy soil it increased ARk at low range of ARk and decreased the ARk value at high range of ARk. The former was presumably attributed to the specific adsorption while the latter was due to the complementary ion effect.
关键词
水稻土
交换平衡
容量强度比
钾
铵
paddy soil
exchange equilibrium
quantity to intensity ratio
potential buffer capacity.
