日光温室栽培土壤供钾状况及K-Ca吸附交换特性研究  

Quantity and intensity of potassium and its exchange relationship with calcium in sunlight greenhouse soils

作　　者：陈竹君[1] 王益权[1] 周建斌[1] 刘晓军[1] 周博[1] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《植物营养与肥料学报》2009年第5期1078-1084,共7页Journal of Plant Nutrition and Fertilizers

基　　金：西安市农业科技攻关项目(GG04094);西北农林科技大学2006年拔尖人才支持计划;西北农林科技大学科研专项(04ZM097)资助

摘　　要：研究了陕西关中地区不同日光温室栽培土壤钾素供应状况及土壤K^+、Ca^(2+)离子吸附交换特性。结果表明,日光温室栽培的土壤钾素Q/I曲线及参数与大田栽培土壤明显不同。温室栽培(土娄)土和潮土钾素活度比(AR_0)较相应大田土壤分别提高了14.8和6.9倍,土壤对外源钾的缓冲能力下降;从K^+和Ca^(2+)+Mg^(2+)的交换自由能看,温室栽培土壤存在钾素过多,K^+和Ca^(2+)+Mg^(2+)离子比例失调问题。不同K^+/Ca^(2+)摩尔比下,随着K^+、Ca^(2+)总浓度的提高,大田及温室栽培土壤对K^+、Ca^(2+)的吸附量均呈线性增加趋势,温室栽培土壤K^+吸附率及两种土壤Ca^(2+)吸附率均呈对数增加趋势。K^+/Ca^(2+)为2:1时,K^+吸附量远大于K^+/Ca^(2+)为1:2.5时的吸附量;K^+/Ca^(2+)为2:1时,温室栽培土壤Ca^(2+)均呈解吸状态。土壤对K^+、Ca^(2+)离子吸附的相对选择性随K^+/Ca^(2+)比例及溶液离子总浓度的变化而变化。K^+/Ca^(2+)为2:1时,土壤对K^+的相对吸附选择性大,K^+/Ca^(2+)为1:2.5时,温室栽培土壤对Ca^(2+)的相对吸附选择性显著增加。加入土壤K^+的比例和数量过高,非但未提高K^+离子的活度,还造成胶体上Ca^(2+)离子的大量解吸,由此可能带来的日光温室土壤胶体稳定性降低及养分不平衡的问题值得关注。Quantity and intensity of potassium and its exchange with calcium in sunlight greenhouse soils are studied in Guanzhong Plain, Shaanxi. Compared to open field soils, the soils under sunlight greenhouse cultivation have different curves of quantity and intensity of potassium （Q/I）. The activity ratios between K^＋, and Ca^2＋and Mg^2＋ ions of the two greenhouse soils （i.e., manural loess soil and fluvo-aquic soil） are about 14.8 and 6.9 times higher than the corresponding field soils, respectively. The buffer capacities of the greenhouse soils to add K^＋ are lower than those of the field soils. The changes of Gibbs free energy of K^＋, and Ca^2＋ and Mg^2＋ exchange （ΔG） of the greenhouse soils indicate there are excessive accumulation of K^＋ ion and imbalances of K^＋ with Ca^2＋ and Mg^2＋ ions in the soils. As increase of concentrations of K^＋ and Ca^2＋ ions in solution, amounts of adsorbed K^＋ and Ca^2＋ ions by the two soils under both greenhouse and field conditions are increased in a linear pattern, and the adsorption rate of K^＋ ion of the greenhouse soils and adsorption rate of Ca^2＋ ion for both the greenhouse and field soils follows a exponential pattern. When the ratio of K^＋ to Ca^2＋ ions added into soils is 2：1, amounts of adsorbed K^＋ by soils are higher than those of 1：2.5 of K^＋ to Ca^2＋ ions, and Ca^2＋ ion in the greenhouse soils is desorbed. The selectivities of soils to K^＋ to Ca^2＋ ions are changed with the ratios and concentrations of K^＋ to Ca^2＋ ions in the solutions. K^＋ ion is preferential adsorbed when the ratio of K^＋ to Ca^2＋ ions added into soils is 2：1, while, Ca^2＋ ion is preferential adsorbed when the ratio of K^＋ to Ca^2＋ ions is 1：2.5. When over-addition of K^＋ ion into the greenhouse soils occurs, activity of K ion is not increased, and Ca^2＋ ion is largely desorbed. This may affect the soil structure and make the imbalance of nutrients in the greenhouse soils.

关 键 词：日光温室土壤 钾素Q/I曲线 K—Ca交换特性 

分 类 号：S158[农业科学—土壤学]