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当前,在营造杨树速生丰产林中,为了灌溉,必须在造林前对林地进行平整,并打井、修渠,修建必要的水利工程。这项投资较大,如一个轮伐期一亩地总投资二百元,它通常占25—30元,若把轮伐期内的灌溉费用再加进去,那么所占比例更大。所以,在不影响生长的前提下,减免灌水是节约投资,降低成本的途径之一。据报导,国外有深栽不浇水的事例,目前我国有些单位也在研究。我们是在1980年春进行深栽试验的,同年秋季对地上、地下部分均进行了调查。1981年秋又对地上部分的生长作了测量。现仅就两年的生长情况初报如下。
At present, in the cultivation of poplar fast-growing and high-yielding forests, in order to irrigate, it is necessary to level the forest land before planting and to dig wells, repair channels and construct necessary water conservancy projects. This investment is quite large. If a total investment of 200 yuan per mu for a rotation period is usually 25-30 yuan, the proportion will be even greater if irrigation costs during the rotation period are added. Therefore, without affecting the growth of the premise, reducing irrigation is one of the ways to save investment and reduce costs. It is reported that there are some cases of deep planting without watering in other countries. At present, some units in our country are also studying. We conducted a deep planting test in the spring of 1980. In the autumn of the same year, we investigated both above and below ground. In the autumn of 1981, the growth of the aerial part was measured. Now only the first two years of growth reported as follows.