Effect of Potassium Application on Yield and Soil Potassium Balance in Maize and Wheat Rotation System

In order to instruct the suitable potassium fertilizer application for maize and wheat production in Henan province,the effect of different potassium fertilizer rate and application technology on yield of maize and wheat,potassium use efficiency and soil potassium balance were studied on high,medium and low potassium supplying soils during 2010-2012.Results showed that maize grain yield were increased by 4.76%~12.49%,7.56%~16.08% and 7.01%~22.61%,respectively,wheat grain yield increased by 6.87%~13.87%,11.19%~18.57%and 18.71%~27.49%,respectively after potassium fertilizer application in high,medium and low potassium soils.Potassium use efficiency of wheat was higher than that of maize in three sites,partial productivity of potassium fertilizer was in the order of high potassium sitemedium potassium sitelow potassium site,while potassium recovery efficiency of high potassium site and agronomy efficiency of low potassium site were higher than that of other sites.When potassium rate was 90or 135kg·hm-2,wheat and maize got the good effect with two-times application.When potassium rate was 45kg·hm-2,it should be applied as basal in maize and top dressed in wheat.When potassium application rate was higher than 45kg·hm-2 on the medium and low potassium soils,basal application could maintain soil potassium balance,but in high potassium site potassium could be surplus when potassium application rate was over 90 kg·hm-2.when potassium fertilizer was applied in two times,potassium balance index was lower,but the soil available potassium was higher.It suggested that the suitable potassium fertilizer application rate with high grain yield and high use efficiency were about 45,90,135kg·hm-2 for high,medium and low K soil,and the good effect was got with two-times application.