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绥德地区约有占总土地面积20%的荒坡。依据土地利用规划,主要作为宜林地,用以造林。这类土地较本地区的农耕地埂为破碎、干旱、陡峻瘠薄,为黄土或红色土,生有白草、狗尾草、鬼箭、阿尔泰紫莞、草木樨状紫云英、高蔓草藤、旱卢苇藁属,羊厌厌、杜柳、达乌里胡枝子等杂草灌木,因而在造林技术上,尚存在着一定的问题。今就有关造林季节、树种、方法等几方面的问题研讨如下。一、造林季节:应依据各个季节的降水、土壤水分、霜冻及树种的造林特性来选择适宜的造林季节。本地区全年降水约400～500公厘,初霜约在十月中旬,终霜在四月中旬,十一月中旬士地开始结冻,三月中旬解冻。全年降水分布及土壤水分(0～30公分及0～10公分)变化情况如下:
Suide area about 20% of the total land area of the barren slope. According to land use planning, mainly as a forest land, for afforestation. This type of land is shattered, arid and steeply barren, and is loess or red soil, with white grass, Setaria viridis, ghost arrows, Altai Purple Wand, Alnus cremastogyne, Prunella vulgaris, drought Lu reticulata, sheep dislike, Du Liu, Lespedeza dahurica and other weed shrubs, so in afforestation technology, there are still some problems. Now on the afforestation season, species, methods and other aspects of the issue discussed below. First, the reforestation season: According to the various seasons of precipitation, soil moisture, frost and afforestation characteristics of species to choose the appropriate reforestation season. The annual precipitation in the region is about 400-500 mm. The first frost is about mid-October. The frost begins to freeze in mid-April and mid-November, and thawed in mid-March. Annual precipitation distribution and soil moisture (0-30 cm and 0-10 cm) changes are as follows: