稻麦轮作下施钾效应及钾肥后效

STUDY ON CONTEMPORARY AND RESIDUAL EFFECTS OF POTASSIUM FERTILIZER UNDER ROTATION OF WHEAT AND RICE

分别在缺钾的宁镇丘陵区白土与太湖平原地区低位白土类型水稻土上进行的钾肥试验表明:一季钾肥(KCI)最佳用量为150～300kg/hm^2。当季小麦可增产16.8%～22.6%:随着钾肥用量的增加。单位钾肥的谷物增产量及当季钾肥利用率随之下降;但4～6季稻麦的钾肥总利用率为90.3%～98.6%,钾肥具有明显的后效,肥料钾在土层中淋移较少,淋移程度与施钾量及剖面质地有关.相同品种和管理措施下,在不施钾情况下,作物吸钾量与产量均随种植次数增加而明显降低.

Different amounts of potassium (KCI) fertilizer were applied to paddy whitish soils deficientin K in hilly land and Taihu region of south Jiangsu under the rotation of wheat and rice.The results showedthat the most adequate KCI application for the first crop was 150～300kg/hm^2,which brought about anincrease of wheat yields by 16.8%～22.6%.As the KCI fertilizer applied in the first crop increased,the in-crease of grain output owing to lkg KCl application and the utilization rate of K fertilizer in the first cropdeereasd,while the total utilization rate in the whole rotation of 4～6 crops reached 90.3%～98.6%,indi-cating the evident resudual effect of K fertilizer.K fertilizer was less leaching and transported in soil layerswithin 50cm vertically.