中文摘要：

为了研究我国华北平原低肥力土壤条件下秸秆还田和施钾肥对作物产量和钾素平衡的影响,于2008年10月～2011年10月在中国农业科学院高新技术园区国家测土施肥中心实验室试验基地（河北省廊坊市）,通过3年6季的定位试验,比较了施钾与秸秆还田的增产效应、钾素吸收利用和作物-土壤系统的钾素平衡状况。结果表明：在氮、磷肥充足的情况下,施用钾肥（NPK）、秸秆还田（NP＋St）和秸秆还田配施钾肥（NPK＋St）,均有明显的增产效应,表现为NPK＋St〉NPK〉NP＋St〉NP;不同施钾措施在夏玉米上的增产效果优于冬小麦;同一作物秸秆还田结合施钾肥的增产效果最好,降低了年度间的产量变异系数,在获得高产的同时,年际间产量稳定,有利于稳产;施钾肥和秸秆还田可显著提高小麦和玉米的钾素吸收总量;NPK＋St、NPK、NP＋St处理的钾素表观平衡系数分别为1.26、0.42、0.92。秸秆还田和施钾肥有利于钾素的收支平衡,减轻作物对土壤钾素的消耗,缓解土壤钾素肥力下降的程度,可维持土壤钾素肥力的稳定。

英文摘要：

In order to study the effects of potassium fertilizer application and straw returning to soil on the yields of winter wheat and summer maize,crop potassium absorption and soil potassium balance,a field experiment was conducted under low soil fertility condition at the experiment site（located in Langfang city of Hebei Province） of National Laboratory of Soil Testing and Fertilizer Recommendation of Chinese Academy of Agricultural Sciences,North Plain of China from 2008 to 2011.The four treatments were designed with NP（no potassium fertilizer and no straw returning to soil）,NPK（no straw returning to soil）,NP＋St（no potassium fertilizer but straw returning to soil） and NPK＋St（potassium fertilizer application and straw returning to soil）.The experimental design was the randomized complete block with three replications and each plot was 50 m2（10 m×5 m）.Both in winter wheat and summer maize seasons,nitrogen and phosphorus application rates were N 180 kg/ha and P2O5 90 kg/ha,the potassium application rate was K2O 60 kg/ha in the treatments with potassium application,and the crop straw returning to field was managed by all winter wheat residue mulching and summer maize residue incorporation with soil.The results indicate the treatments of NPK,NP＋St and NPK＋St could significantly increase the crop yields with the same N and P application rates,the yield increment effects are NPK＋St 〉 NPK 〉 NP＋St 〉 NP.The different management practices have better yield effects in summer maize season than those in winter wheat season.The treatment of NPK＋St has the highest crop yields and decreases the variation of crop yields in different years,which is benefit to sustain high crop yield.The potassium application and crop returning to soil have no significant effects on the potassium contents in grains or straws of the crops,however,which significantly improves the corps shoot absorption.Indies of potassium balance of the treatments of NPK＋St,NPK and NP＋S are 1.26,0.42 and 0.92,respectively.