多年定位施肥对紫色土钾素形态变化的影响

在西南农业大学国家紫色土肥力与肥料效益监测基地上 ,研究多年定位施肥对紫色土钾素形态变化的影响。研究结果显示 :施钾各处理 0～ 2 0cm和 2 0～ 40cm土层土壤水溶性钾、非特殊吸附态钾、特殊吸附态钾下降不明显 ,基本能保持在试验初期 ( 1991年 )的水平上 ,不施钾处理则呈现明显下降趋势 ,这表明施钾能维持紫色土速效钾 (水溶性钾 +非特殊吸附态钾 +特殊吸附态钾 )的平衡。不论施钾与否 ,各处理 0～ 2 0cm和 2 0～ 40cm土层土壤非交换性钾、矿物钾呈下降趋势 ,其中不施钾处理土壤非交换性钾下降更明显

The Effect of Long-term Fix-point Application on the Potassium Forms in Purple Soil

The experiment, whose purpose was to study the effect of long-term fix-point applied fertilizer on the change of potassium forms in purple soil, was carried out on the National Purple Soil Fertility and Fertilizer Efficiency Monitored Base in Southwest Agricultural University. The results are the following: Water soluble K, nonspecifically absorbed K and specifically absorbed K in surface soil (0～20cm) and subsoil (20～40cm) are balanced in all applied K treatments, while having an obvious descending trend in nonapplied K treatments. These results show fast available K (water soluble K+nonspecifically absorbed K+specifically absorbed K) in purple soil is balanced by applying potassium. Nonexchangeable K and mineral K in the two layers (0～20cm and 20～40cm) have a descending trend in all treatments, and the former decreases more in nonapplied K treatments than in applied treatments.