连续施钾对黑土钾素动态变化的影响

采用定位方法研究黑土连续施用钾肥对土壤钾素动态变化及产量的影响。结果表明 ,连续 7年施钾肥玉米仍表现明显的增产效果 ,不施钾肥耕层土壤速效钾含量逐年降低 ,导致掠夺式生产 ;不施钾肥耕层土壤缓效钾含量明显下降 ,施钾肥土壤缓效钾略有下降 ,起到一定的缓解作用。施K2 O 1 1 2 .5kg/hm2 ,钾的平衡系数为 0 .96,说明钾的投入和消耗基本平衡 ;施K2 O2 2 5kg/hm2 ,钾的平系数为 1 .3 4,说明钾肥投入大于作物携走的钾 ,外源钾在土壤中有较大的剩余。

Inflaence of successive application of Potnsh on the Dynamic Change of Potassinm in Black Soil

The method of fixed site field was adopted in the experiment for the study of potassium fertilizer application on the effect of dynamic change of potassium content in the soil of cultivated layer. The result showed that with potash application continuously for 7 years, it still showed a positive effect on corn yield. The result also showed that without potash application the available K content in the soil decreased significantly, the soil fertility was plundered by crop production like this. Without potash application the slow released K content in the soil decreased obviously, but with potash application it decreased slightly. With potash application at the rate of K 2O 112.5 kg/hm 2, the balanced coefficient of potassium content in the soil was 0.96.It means that the input and out put of potassium was nearly equal. With potash application at the rate of K 2O 225 kg/hm 2, the balanced coefficient of potassium content in the soil was 1.34. It means that the input of potash was more than that of out put, the potassium fertilizer has some surplus in the soil.