滨海旱地潮土供钾能力研究

Study on the potential of potassium supply in coastal upland soil

采用化学测定和生物耗竭试验，研究不同肥力旱地潮土供钾能力。结果表明：潮土土类的三个土种在土壤供钾强度、供钾容量、供钾潜力、生物吸钾量、连续种植后土壤钾的下降量，均以半夜阴地＞夜阴地＞黄泥翘土壤；而土壤钾缓冲容量、钾最大吸附量的排序则相反。连续密集种植的生物试验结果表明，土壤供钾以土壤缓效钾部分占７８～８９％，而土壤速效钾供钾只占１９～２２％。土壤速效钾降低至一定程度后不会持续下降而维持在耗竭水平值，在临界点以后，主要依赖土壤缓效钾供钾。旱地潮土供钾能力都不能满足作物生长的需要，不施钾肥作物的吸钾受到限制，其含钾量、相对生物产量明显下降，连续施用钾肥能产生较大的增产效应。

The potential of potassium supply in coastal upland soil was studied adopting chemical analysis method and the green house experiment of biological exhausting. Results showed that the intensity, capacity and potency of potassium supply, the plant absorption quantity for potassium and the soil potassium decreasing quantity while successive intensive planting, were ranged in the order of banyeyindi<yeyindi<huangniqiao soil species, while the potassium buffer capacity and potassium adsorption of soil was on contrary. The result of successive intensive planting indicated that soil unexchangable potassium account for 78～89% of soil potassium supply to plant, and soil exchangable potassium only account for 19～22% of that. The soil available potassium never continuously decrease to zero, but it maintained on exhausted level value. When the exhausted level is reached unexchangable potassium is mainly supply source of soil potassium to plant. Supplied potassium of coastal upland soil tested was not enough so that potassium content and biomass of plant without K treatment obviously decreased. Potassium application in coastal soil increased biomass and yield of crops.