<正>对徐淮平原杨树林带胁地段内小麦产量的变化规律进行分析。结果表明,农田林网内的小麦产量存在着明显的减产区、平产区和增产区。林带侧0.4H(H为林带平均高度)范围内为减产区,0.7H左右为平产区,0.7H以外为增产区;林带对其北侧和西侧小麦的影响严重,且影响范围较大,而在林带南侧和东侧的小麦所受胁地影响较轻;林木冠幅(平均投影面积)对近林带处小麦的产量影响较大。在影响农作物产量的主要因素中,树冠遮荫对小麦的生长发育有着更加明显的抑制作用;林带断根措施可有效防止根系从农田土壤内吸收水分和养分,能够在一定程度上降低林带树木根系的胁地影响。

Based on the analysis to the influence disciplinarian of poplar shelter forest belts on the output of wheat,the paper shows that the wheat output nearby the shelter forest belts are changed much because of the belt influence.There exist reduction area,increasing area and normal area of wheat output from shelter forest belts to the farmland.In the range from the belt to 0.4 H,the wheat output is decreased.And the output is the same as comparison area in the range from 0.4 H to 0.7 H.But the output is increased greatly in the range from 0.7 H to the farmland.The outputs of wheat at south and east sides of shelter forest belts are influenced lightly,but they are strongly at north and west sides.Among the influent factors,the projection area of tree crown has a great affect on wheat output.The coverage of crown can restrain the wheat output obviously.Root system cutting measures can protect the tree roots growing into farmland.The negativeeffect of shelter forest belts on wheat output can be decreased efficiently.