我省各地对于苗木越冬防寒,积累了丰富的经验,目前,主要采取如下几种方法:(1)覆土防寒法此法适用于油松、樟子松、红松、沙松等针叶树的一年生幼苗,或板栗、核桃等抗寒能力较弱的阔叶树幼苗的越冬防寒。具体做法:覆土防寒要在土壤结冻前2—3天进行。先用犁将垄沟(或步道)趟起,然后将碎土向垅(床)面一方覆盖,使苗梢向一边倾倒,不要从苗上头向下盖土。覆土厚度要超过苗梢3—4厘米,盖后耙平,并将垅(床)两侧的暄土拍实,覆土前宜侧灌一次水,以利保墒,防止春旱。覆土要覆匀、埋严,以免土壤透风引起冻害。覆土后要经常检查,发现露苗及时补盖。待翌春起苗前一周,分两次撤去覆土,这样有利于苗木逐渐适应环境条件的变化。撤土不宜过迟,否则覆土化冻下沉,粘附苗木影响生 At present, we mainly adopt the following methods: (1) Cover soil cold-proof method This method is suitable for the annual seedlings of conifers such as Pinus tabulaeformis, Pinus sylvestris, Pinus koraiensis, Pinus sylvestris and so on. , Or chestnut, walnut and other hardy cold hardwood seedlings overwinter cold. Specific practices: Cover soil cold to 2-3 days before freezing in the soil. Plow the furrows (or trails) first, and then cover the ground with one side of the bed so that the tip of the trees will fall to the side. Do not cover the soil from the top of the seedlings. Cover soil thickness to more than 3-4 cm Miao, rake flat cover, and 垅 (bed) Xuan soil on both sides of the filming, soil cover before a lateral irrigation water to facilitate soil moisture, to prevent spring drought. Covered soil should be uniform, buried Yan, so as to avoid soil damage caused by air permeability. After the casing should be checked regularly and found that Lumiao timely cover. To be picked up the next spring before the emergence of seedlings, remove soil twice in two, so conducive to seedlings gradually adapt to changes in environmental conditions. Soil withdrawal should not be too late, otherwise soil subsidence thawing, adhesion of seedlings affect students