摘要
采用幼苗密集种植、尼龙网分隔根-土界面的方法研究小麦根际微区土壤交换性钾与缓效钾的动态变化。结果表明,小麦根际微区内,仅在根表的1 mm 范围内交换性钾呈现相对富集,其他部分的交换性钾呈亏缺状况,其亏缺率与亏缺范围因土壤质地和施钾量的不同而有改变。砂土钾的迁移速率大于轻壤土。前者的亏缺区也大于后者,增施钾肥后根际交换钾的亏缺率增大,加速了钾向根表的迁移和供应。此外,小麦根际微区的缓效钾也呈现亏缺状况。
The distribution of exchangeable-K and slowly available-K in rhi- zosphere of wheat were studied by box-cultured experiment with thick planting seedling,and nylon sieve net was used to screen interface of too system and soil. The result shown that the depletion of exchangeable-K was found in almost all the rhizosphere except the distance of 1mm from root surface where the re- lative accumulation of exchangeable-K occured.The Percentage and distance of exchangeable-K depletion depended on the grades of soil texture and rates of Po- tassium fertilizer applied.The distance of depletion in soil is wider in the sandy soil than in the light-loam soil.The application of potassium fertilizer increased the movement of K from bulk-soil to root-surface,and improved the capacity of soil supplying potassium to wheat roots.The experiment also indicated that there was slight depletion of slowly available-K in the proximity of roots of wheat.
关键词
小麦
根际
交换钾
缓效钾
rhizosphere of wheat
bulk-soil
depletion
accumulation
exchangeable-K
slowly available-K
