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该文以１０ａ生旱地毛白杨用材片林为试材，分析了河北平原农区旱地片林改造的必要性。试验结果表明：投资年均效果系数林地为２．３６，介于相同土壤类型的农田（１．４５）和梨园（２．８９）之间。平均年纯收入以林地最低，为２９２５元／ｈｍ￣２，农田为３３８８元／ｈｍ￣２，是林地的１．１６倍，梨园为１９１５９．５元／ｈｍ￣２，是林地的６．５５倍。７～１０ａ生的４年间，林地纯收入分别只有农田的７３％、８５％、５３．８％和２６％。片林改造后的间作地纯收入为６１１５元／ｈｍ￣２，是同年度林地纯收入的４．６５倍。林地水分和光照试验表明，造成林木生长减慢和牧草无法生长的主要原因是土壤水分亏缺。
In this paper, 10 000 dryland Populus tomentor woods as test materials, analysis of the necessity of the transformation of dry land in Jilin plain. The test results show that the average annual coefficient of investment of forest is 2.36, which is between that of the same soil type (1.45) and pear orchard (2.89). The average annual net income to the lowest forest, 2925 yuan / hm ~ 2, farmland 3388 yuan / hm ~ 2, 1.16 times the woodland, pear orchard 19159.5 yuan / hm ~ 2, 6.55 Times In the four years from July to October 10a, the net income of forestland was only 73%, 85%, 53.8% and 26% of the farmland respectively. The film after the transformation of the intercropping net income of 6115 yuan / hm ~ 2, 4.65 times the net income of the same year. Woodland water and light tests showed that the main reason for the slow growth of forest trees and the unfertility of pasture was soil water deficit.