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通过对民勤绿洲巴丹吉林沙漠边缘25条农田防护林带的详细调查,研究农田防护林对林带生态环境要素影响和林下作物的生长状况。结果表明:1)农田防护林对林下作物叶面积有显著影响(P<0.05),主要集中在林下1倍树高范围内;2)农田防护林土壤含水量和土壤温度均有显著影响,随着与林带距离的增加,不同深度土壤含水量呈增加趋势(F=4.446,P=0.001),而土壤温度的变化随距林带的距离的增加而降低(F=32.430,P=0.000);3)农田防护林对作物产量的影响距离树高1/2倍处单位面积产量与对照组比较明显降低(P(0.05),与1倍、3倍树高处相比,也明显降低(P(0.05),在距离树高3倍处,农田产量达到最大值。与无防护林对照样地平均单位产量比较,农田防护林间距较大的农田平均单位产量与对照样地比较增产8.84%,但是农田防护林间距较小的农田出现减产现象,减产约7.49%;4)随着距离的增加两个高度防护林的防风效能均逐渐增大(F=482.749,P=0.000),距离地面100cm林带的防风效能明显高于距离地面200cm的防风效能(P(0.05)。
Through the detailed investigation of 25 farmland shelterbelts on the edge of Badain Jaran Desert in Minqin Oasis, the impact of farmland shelterbelt on the eco-environmental factors of forest belts and the growth of understory crops were studied. The results showed that: 1) The farmland shelterbelts had a significant effect on the undergrowth leaf area (P <0.05), mainly in the range of 1 times the tree height. 2) Both the soil moisture content and the soil temperature in the shelterbelts significantly affected (F = 4.446, P = 0.001). However, the change of soil temperature decreased with the distance from the forest belt (F = 32.430, P = 0.000); 3 ) The effect of farmland shelterbelt on crop yield was significantly lower (P (0.05)), and the yield per unit area at 1/2 times the height of tree was significantly lower than that of the control (P (0.05) ), And the farmland yield reached the maximum at 3 times of the tree height.Compared with the average unit yield of unprotected forest land, the average yield of farmland with larger farmland shelterbelts increased by 8.84% compared with the control plots, but the spacing of farmland shelterbelts 4) As the distance increases, the windbreaking efficiency of two high shelterbelts gradually increases (F = 482.749, P = 0.000), and the windbreaking efficiency of the shelterbelt at 100cm above the ground is significantly higher Windproof performance at a distance of 200 cm from the ground (P (0.05)).