论文部分内容阅读
我国北方地区,冬季气候寒冷,春季风大干旱,气温变化剧烈,对一些针叶树和抗寒力弱的阔叶树幼苗,要采取有效的防寒技术措施。严寒对苗木的危害,有直接的冻害,也有间接的冻拔、冬季旱害等。前者多为早、晚霜造成的;后者冻拔是由于土壤中的水分冻结,体积膨胀,将苗木的根部拔起而使苗木死亡,主要发生在潮湿苗圃地,而冬季旱害则是由于风大苗木水分蒸腾大,得不到补充而发生干枯或死亡。预防苗木受霜冻和寒风危害可分别采用如下的几项技术措施。 1、用草或落叶覆盖苗木。
In the northern part of our country, cold weather in winter and severe spring monsoon have severe changes in temperature. For some coniferous trees and hardy weaker hardwood seedlings, effective cold-proofing and technical measures should be taken. Cold on the hazards of seedlings, there are direct frost damage, but also indirectly frozen, winter drought and so on. The former is caused mostly by morning and evening frost. The latter is due to freezing and volume expansion of the water in the soil, which leads to the death of the nursery stock mainly in moist nurseries. In winter, drought is caused by wind Large nursery stock water transpiration, without supplementation and dry or died. Prevention of frost and cold damage by seedlings can be used as follows several technical measures. 1, grass or leaves covered with seedlings.