农林间作对防风固沙林生长量的影响

黄淮海平原的沙地立地条件差,防风固沙林和农田防护林常因生长不良而达不到预期的防护作用,难以消除风蚀对农业生产的影响。在白榆人工林内进行的农林间作试验表明:不同的间作类型和不同的间作年限,均对防风固沙林的生长有显著影响;连续间作1～5年,林木年均高生长可提高40.43％～78.7％,胸径年均生长量可提高25.71％～89.11％,一般连续间作3～4年,林木即可进入稳定生长期,而以造林后的前两年作用最大;不同的间作物作用不同,比较理想的间作物是油菜、花生、豆类等低秆作物。

Effects of Intercropping Crops and Forest On the Growth of Forest for Wind-Breaking and Dune-Fixing

Because the site factors of Huang-Huai - Hai Plain are poor, the wind - breaking and dune -fixing forest or the shelter -forest can not grow well for protecting the farmland as expected. So it is difficult to e-liminate the effects of wind erorion on agricultural production. Experiments of intercropping crops and forest trees carried out in artificial white elm forest show that different intercorpping types and numbers of years have obvious effects on the growing of wind-breaking and dune-fixing forests; that continuously intercorp-ping for one to five years can increase growth in length by 40. 4 to 78. 7 percent, growth in diameter by 25. 7 to 89. 1 percent annualy. Generally, trees can enter into a steady growing period after three to four continuously intercropping years, and the first two years have most effects. Different intercropping crops have different effects. Ideal crops are rape, peanut and beans which have low stalks.