河套灌区的农田防护林建设,大部分是按渠系配置,每年四月下旬在灌水渠上用大苗造林。但由于农业用水多在五月中旬以后,造林后不能立刻浇水。加上风大、干旱、蒸发强烈,新栽树苗往往发生抽梢现象。即使有些苗木靠自身的水分萌芽展叶,终因为失水而萎蔫。最好的结果也只能从根部重新萌蘖。活是活了,但是林木高低不一,林相不整齐,经济效益、防护效益差,达不到一次成林、快速成林的目的。 The construction of farmland shelterbelt in Hetao Irrigation District is mostly configured according to canal system. Afforestation is carried out with large seedlings on irrigation channels in late April each year. However, since agricultural water is mostly used in mid-May, watering can not be done immediately after afforestation. Coupled with the wind, drought, strong evaporation, the newly planted saplings often happen shoot tip phenomenon. Even if some seedlings nurture the leaves by their own moisture, and eventually wilted due to water loss. The best result can only be sprouted again from the roots. Live is alive, but different levels of forest, forest is not neat, economic benefits, poor protection benefits, reach a forest, rapid succession purposes.