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练塘公社林家草大队在搞农田基本建设的基础上,从1972年起就开展了植树造林。目前,农田四周已绿树成荫,实现了农田林网化。林带共植白榆树、水杉1558株,平均树高10～12米,总活立木蓄积量约106立方米。林网化还有利于提高作物的产量。对此,我们于1980～1981年进行了气候效应测定和后季稻、三麦、早稻产量的观察研究,结果如下: (一)气象效应:1.林网能降低风速。树木在着叶期内降低风速40％,落叶期降低25％,始叶期降低30％以上。后季稻期间风速减弱程度最大的是在主风方向背风面,林带树高的3～10倍处和在迎
Liantong commune Linjiancao brigade engage in farmland capital construction on the basis of starting from 1972 on afforestation. At present, the farmland has been tree-lined around to achieve the network of farmland forest. White altair trees planted with forest, Metasequoia 1558, the average tree height of 10 to 12 meters, the total live stump volume of about 106 cubic meters. Lin network also helps to increase the crop yield. In response, we conducted a climatic effect measurement and post-crop rice, three wheat, early rice yield observation from 1980 to 1981, the results are as follows: (a) meteorological effects: 1. Lin network can reduce wind speed. Trees reduce the wind speed by 40% during the leaf period, 25% during the deciduous period, and more than 30% during the early leaf stage. The wind speed weakened in the latter part of rice is the leeward in the main wind direction, the tree height 3 ~ 10 times and in the welcome