长期施钾对东北春玉米产量和土壤钾素状况的影响

 【目的】为探明长期施钾对大田玉米产量和耕层土壤钾素状况的影响。【方法】本文通过在东北三省的代表性土壤上连续13年的定位施钾试验进行研究。【结果】东北3个定位试验点在施用氮磷肥基础上长期施钾对玉米产量的影响差异较大，辽宁13年间（1993～2005）施钾效应不稳定，吉林自第3年（1995年）开始施钾显著增产，黑龙江自定位开始施钾显著增产；辽、吉、黑3点长期施钾条件下作物产量13年平均分别增加9.9%～10.3%、12.6%～13.6%和17.5%～21.7%。辽宁、吉林两点施K2O 112.5 kg•ha-1时土壤-作物系统内钾素处于较明显的亏缺状况，而施K2O 225.0 kg•ha-1时3个定位点钾素均有较多的盈余。长期施钾均能显著增加土壤速效钾含量，且土壤速效钾含量随施钾量的增加而增加，而长期施钾对3个定位点缓效钾含量的影响有所不同。【结论】基于产量、效益和土壤钾素状况，3点的适宜钾（K2O）用量为112.5 kg•ha-1左右。

Effect of Long-term Application of K Fertilizer on Spring Maize Yield and Soil K in Northeast China

Using the 13-year fixed site field trials located at selected locations in three provinces of northeast China, Liaoning, Jilin and Heilongjiang, effect of K fertilizer use on maize yield and soil K status in the plough layer was studied. Results showed that effect of K application on maize yield was quite different between the three fixed sites. In the field trial in Heilongjiang, significant maize yield response to K was found starting in the first year; in Jilin, the significant yield response to K was found starting in year 3; while in Heilongjiang, the maize yield response to K was not very stable from 1993 to 2005. The ranges of yield response to K fertilizer application in the field trials in Liaoning, Jilin and Heilongjiang were 9.9%-10.3%, 12.6%-13.6% and 17.5%-21.7%, respectively. In all three sites, K balance in soil-crop system was negative in the treatment with K2O application rate at 112.5kg/hm2, and remarkable K accumulation in soil was found when K2O application rate was 225.0 kg/hm2. Application of K fertilizer significantly increased soil available K content, and the increase in slowly available K in soil was not significant. Considering maize yield and income and soil K status, suitable, quantity of K fertilizer (K2O) was 112.5 kg/hm2 under present experimental conditions.