六、浅湿干交替间断灌水水稻一生对水分要求和适应能力是有差别的。有两个时段抗旱力最强：一是苗期，特别是三叶期之前；二是有效分蘖终止期（即够苗期）至幼穗分化前。因为三叶期前，稻苗处于自养为主；有效分蘖终止期，要求控上促下，既有利于根系深扎，又有利于抑制无... Sixth, alternating wet and dry alternating intermittent irrigation Rice’s lifetime requirements and adaptability to water is different. There are two periods of strongest drought resistance: First, the seedling stage, especially before the three-leaf stage; the second is the effective termination of tillering (that is, seedling stage) to pre-spike differentiation. Because of the three-leaf stage, rice seedlings in the autotrophic-based; effective tillering termination, requiring control on the promotion, both conducive to the root deep-tie, but also conducive to the inhibition of ...