POTASSIUM RELEASE KINETICS AND PLANT-RESPONSE IN CALCAREOUS SOILS
POTASSIUM RELEASE KINETICS AND PLANT-RESPONSE IN CALCAREOUS SOILS
复制标题
DOI：
10.2136/sssaj1985.03615995004900020019x
复制
发表时间：
1985-01-01
影响因子：
2.9
通讯作者：
WESTFALL, DG
中科院分区：
文献类型：
--
作者：
HAVLIN, JL;WESTFALL, DG
通过室内和温室试验，研究了石灰性土壤钾素供应和非交换性钾素释放的动力学特征。在12个土壤中分别种植紫花苜蓿（Medicago sativa L.）在温室中进行584 d（16次扦插）。产量，钾的吸收，并在NH 40 Ac [乙酸铵]交换性钾的变化进行了监测。在实验室（7000 h浸提）测定了每种土壤< 0.25 mm粒级的Ca树脂浸提钾。根据温室和实验室数据计算了非交换性钾释放量。累积释放到钙树脂的钾的数学描述的幂函数方程和经验常数有关的苜蓿产量，钾吸收，和交换性钾水平。粘土土壤具有长期的植物有效钾供应，而轻质地土壤没有。经16次扦插后，粘土、壤土和砂土的交换性钾含量分别下降了44%、33%和58%。两种独立的方法测量非交换性钾释放高度相关（r = 0.91）。钾释放也高度相关的初始NH 4 OAc-K和累积或相对K吸收和产量。幂函数动力学方程的截距和斜率常数与苜蓿产量、吸钾量和初始交换性钾呈显著正相关。NH 4 OAc-K土壤试验是这些土壤长期供钾的适当措施。
Greenhouse and laboratory experiments were conducted to characterize the K supply and nonexchangeable K release kinetics in calcareous soils. Twelve soils were exhaustively cropped with alfalfa (Medicago sativa L.) in the greenhouse for 584 d [day] (16 cuttings). Yield, K uptake, and changes in NH4OAc [ammonium acetate] exchangeable K were monitored. Ca resin extractable K was determined in the laboratory (7000 h extraction) on the < 0.25 mm fraction of each soil. Nonexchangeable K release was calculated from the greenhouse and laboratory data. Cumulative K release to Ca-resin was mathematically described by a power function equation and the empirical constants related to alfalfa yield, K uptake, and exchangeable K levels. Clay soils had a long-term supply of plant available K while light-textured soils did not. After 16 cuttings the exchangeable K levels in the clay, loam and sand textured soils declined 44, 33 and 58%, respectively. Both independent methods of measuring nonexchangeable K release were highly correlated with each other (r = 0.91). K release was also highly correlated to initial NH4OAc-K and to cumulative or relative K uptake and yield. Intercept and slope constants of the power function kinetic equation were significantly correlated to alfalfa yield, K uptake, and initial exchangeable K. The NH4OAc-K soil test was an adequate measure of long-term K supply in these soils.