黑土地区钾肥对大豆产量效应的研究

黑龙江省有机质含量一般低于４％的黑土，在施用一定氮肥、磷肥和有机肥的基础上，增施适量的钾肥，大豆产量均有明显提高。大豆施钾肥，在气候干旱和降水偏多的条件下，均影响钾的有效性。在干旱的年份施钾肥能提高大豆的抗旱能力；钾在积温较高地区比积温偏低的地区，对大豆增产贡献大；有机质含量较低（２％）的土壤，在氮肥、磷肥和有机肥不同数量配比下，钾肥的效应随氮、磷肥用量增加而提高。氮肥、磷肥投入水平高时，不施钾肥或供钾不足，严重影响氮肥和磷肥的增产效应。在氮肥、磷肥投入较低时，钾肥的增产效应也不能充分发挥。氮磷钾肥之间存在明显的正交互作用。对于我省土壤肥沃度中等或较低的地区，必须实行氮磷钾平衡施肥，才能获得较高的大豆产量。

STUDIES ON EFFECT OF POTASSIUM FERTILIZER ON SOYBEAN YIELD IN BLACK SOIL REGION

Soybean yield from black soil containing below 4% organic matter in Heilongjiang Province can be remarkably improved when certain amounts of N, P and manure are applied and proper rate of K fertilizer is supplementcd. Potassium application will influence its availability under dry climate and too much precipitation. In dry years pofassium. application can improve soybean drought resistance. In highly accumulated temperature region potassium can make more contribution to soybean yield than in lowly accumulated temperatare region. In the Soil with organic matter content below 2% the effect of K increasts with the increasing applieation of N and P. High applieation of N and P with no or unsufficient potassium fertilizer will seriouly affect yieed-increase effcet of N and P, while low applieation of and P, will not make the most of yield-increuse effcet of potassium. There is a positice interrelationship anong N, P and K. Therefore, in arder to get high soybean yilld from the soil With OrganiC matter content below 4% it is necessary to practise batanced application of N, P and K.