土壤钾素的有效性及其评定方法的研究

用生物耗竭试验法研究了在不同供钾潜力土壤上,植物对钾肥的反应,植物对土壤钾和肥料钾的利用。不同供钾潜力土壤的钾素有效性是不同的,通过植物吸收,速效钾和缓效钾均有不同程度的降低,植物吸钾量中部分来自矿物钾,但矿物钾释放量只占矿物钾总量的0.04—1.58%。矿物钾的释放很慢,不能满足植物迅速生长的需要。用阳离子树脂袋法和其它化学方法与生物法进行了比较。用树脂袋法和生物法测得的矿物钾释放量,二者接近。树脂袋法的提取量同水稻和大米草吸钾量也很接近,而且二者的相关性均达到0.916^**树脂袋法较生物法简便。

STUDIES ON AVAILABILITY OF POTASSIUM IN SOILS AND ITS EVALUATING METHODS

Studies on response of crops to potassium, and use of fertilizer-and soil-potassium in soils with different potassium supply potentials were made with successive cropping. The availability of potassium,varied with different potentials of potassium in soils, but both available and, slowly available potassium contents decreased in varying degree with the uptake of potassium by crops. The potassium in plant was partly the potassium released from minerals which constitutes only 0.04-1.58% of total mineral-potassium. The mineral potassium is released too slow to meet the requirement of a crop during the growing season. Comparison between the canon-exchange resin bag method and chemical or biotic methods in determining potassium release from minerals showed that the results obtained by resin bag method and biotic method were quite similar. The amount of potassium extracted by resin bag method was also very close to that taken up by rice or Sparrina artglica (r=0.916^**).It was also indicated that resin had method is more convenient than the biotic one.