深松土对玉米根系生长发育的影响

田间试验与调查研究表明：吉林省大部分玉米产区土壤有坚实的犁底层存在，此层位于地表下约２０ｃｍ，其坚硬度约为耕层的３倍，厚度范围为７～１１ｃｍ。采用深松措施打破犁底层，可明显地降低土壤的坚硬度，增加土壤的蓄水保水能力，改善根系生长的生态条件，促进根系生长，使根干重显著增加。打破犁底层后，各层土壤中根量分布都有明显的下移趋势，而且能提高玉米生长后期的根系活力和抗逆性，使玉米百粒重增加２．６％～３．１％。深松后第二年也有增产后效的作用（增产７．８％～８．６％），并且胜于当年（增产６．２％～８．０％），深松土同时结合深施肥效果更佳。

Effect of Subsoiling on Root Growth of Maize

The field experiments and investigation showed that in the most corn-planting areas of Jilin province there existed a solid plough pan, which usually lays at the depth of about 20 cm, with a thickness of 7～11 cm, a solidity of three times as that of plough layer. It was proved that breaking the plough pan by subsoiling improved the ecological conditions with a significant reduction of solidity, an increase of soil capacity on water depositing and holding. So subsoiling promoted the growth of corn root system, and the dry weight of roots increased obviously. The distribution of corn roots in various soil layers tended to go down after the measure,which increased root activity and led to a better drought resistance in the late period of corn growth and the increase of about 2.6 ％ to 3.1％ grams per 100 grains. The total increase of corn yield ranged from 6.2％ to 8.0％ in the first year but from 7. 8％ to 8.6％ in the following year. These effects were even evident when breaking plough pan was combined with a deep application of fertilizer.