合理密植产量高,这是人们熟知的农业生产措施。实践同样证明,柑桔也要合理密植才能高产(见表一)。但是,柑桔是多年生果树,随着树龄的长大而树冠也迅速扩大,树冠增长至枝叶交叉封行后,就显得过密不合理了。柑园密蔽后,因影响通风透光,内部枝叶干枯,结果位置由中下部转到顶端平面,树势和产量都急剧下降。为了解决密植封行后的问题,我们于一九七○年搞间伐试验,七一年起进行大量间伐,四年共伐去柑树近万株,虽然结果柑树减少3.8%,而每年总产量都比间伐前增加40%以上。我们认为采 Reasonable dense planting high yield, which is well-known agricultural production measures. Practice also proved that citrus should be close planting density to high yield (see Table I). However, citrus is a perennial fruit tree, with the age of the canopy and the crown has also rapidly expanded, canopy growth after the cross-seal of branches and leaves, it seems too close unreasonable. After the citrus orchard is closed, the branches and leaves are drained due to the effects of ventilation and light, and the results are transferred from the middle and lower parts to the top plane. In order to solve the problem after the Dacia seal, we conducted a series of thinning tests in 1970 and a large number of thinning measures since July 2001. Nearly 10,000 trees of citrus trees were harvested in four years. Although the results were 3.8% less, Output increased more than 40% before thinning. We think mining