长期不同施肥对青海小麦产量和土壤钾素的影响

以连续实施20年的长期定位施肥试验为研究对象,探讨长期增施钾肥和秸秆还田对青海东部农业区春小麦产量及农田土壤钾素的影响.结果表明：春小麦10年累计产量各处理从大到小排序为NPK＋ 50％ ST＞ NPK＞ NPK＋100％ ST＞ NP＋100％ ST＞ NP＋ 50％ ST＞ NP,长期施肥条件下春小麦产量有年际波动,增施钾肥和秸秆还田能够增加或维持春小麦产量;长期单施氮磷化肥,土壤速效钾含量有下降趋势,增施钾肥和或秸秆还田,能够明显提高土壤速效钾含量,增幅达到13.5％～260％,增加土壤钾素含量,提高土壤钾库贮量.长期施肥和秸秆还田具有很好的补充土壤钾素的作用,在当地条件下秸秆还田可以作为替代无机钾肥的重要措施.

Effects of long-term different fertilization on grain yield and soil K in Qinghai Province

A 20 -year fixed site field experiment was conducted to investigate effects of chemical K fertilizer and straw return on grain yield and soil K in eastern agricultural area of Qinghai province, Qinghai - Tibetan Plateau. The results showed that the high to low order of the ten year accumulated yield among treatments was NPK ＋ 50% ST 〉 NPK 〉 NPK ＋ 100% ST 〉 NP ＋ 100% ST 〉 NP ＋ 50% ST 〉 NP although yearly yield was always effeeted by some abnormal climate and rainfall. Application of K fertilizer and straw return sustained and improved grain yield of spring wheat. Long - term application of N, P chemical fertilizer decreased soil available K content, while addition of potash and or straw return increased soil available K significantly by 13.5% -260%. Addition of potassium fertilizer or straw return can increase soil K content and make soil K pool abundant, and straw return may work as substitute of chemical K fertilizer under local agriculture conditions.