论文部分内容阅读
在水稻集约栽培中,缺钾常成为限制高产的因素。许多文献推荐在最后一次整地时施钾和磷作为底肥。日本最早发现,当钾肥作为追肥或分施能大大提高产量。追施钾的较好时间是抽穗前35—40天左右。最近在印尼和菲律宾,进行了一系列试验,在四次不同时间的处理中,以最大分蘖期施钾产量最高。稻株刚移栽时,对钾的需要量很小,在最大分蘖期和抽穗期之间达到了高峰。钾肥的有效性在植物早期生长阶段常是最高的。水稻幼苗的根与老的根能更有效地吸收钾。钾的吸收与根的呼吸有关系。随着时间推移,淹育土壤中氧气含量减少。老根氧的排泄越来越少,根吸收钾的能力就减小。
Intensive cultivation of rice, potassium deficiency often become a limiting factor for high yield. Many references recommend applying potassium and phosphorus as a base fertilizer at the last site preparation. Japan first discovered that when potash fertilizer as a top dressing or application can greatly increase production. The best time to topdress potassium is 35-40 days before heading. Recently a series of experiments were conducted in Indonesia and the Philippines where potassium was applied at maximum tillering stage at four different times of treatment. Just transplanting rice plants, the demand for potassium is small, reached the peak between the maximum tillering and heading. The effectiveness of potash is often the highest in the early stages of plant growth. Roots and roots of rice seedlings absorb potassium more efficiently. Potassium absorption and root respiration have a relationship. Over time, oxygen content in flooded soils diminishes. Root excretion of oxygen less and less, the ability of the root to absorb potassium is reduced.