苏南白土钾素供应状况的研究

STUDY ON THE POTASSIUM STATUS OF THE WHITISH SOILS IN SOUTHERN JIANGSU PROVINCE

本试验通过对江苏省苏南地区12种白土进行盆栽试验和室内培养,并以兴化县黑粘土作对照,用一般化学方法和电超滤方法研究白土的供钾状况。试验结果表明:白土的供钾数量、供钾速率均较低;其固钾能力较强,但被固定的钾可在短期内为作物重新吸收利用;被强烈耗竭后,白土的交换性钾在非淹水条件下短期内难以恢复到原有水平。在研究缺钾土壤时,电超滤的方法比一般化学提取方法更好。

In order to make recommendation for proper application of potassium fertilizer tosoils short of potassium supply,this research was carried out to characterize thepotassium supply of 12 whitish soils of Southern Jiangsu Province by the methods ofconventional chemical extraction and electro-ultra-filtration(EUF).Results of the potexperiment and incubation show that the amount of available K and the rate of K supplyof whitish soils are much lower than the check soil(Xinghua Black Clay Soils).Ability offixation is also stronger,but the fixed K may be released within a short time.Exchangeable K of thoroughly exhausted whitish soils,if not submerged afterwards,willremain at a low level in at least 40 days.EUF is a more valuable method than chemicalextraction to evaluate the potassium status of whitish soils.