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生物措施因子(B)能够定量衡量植被覆盖对土壤侵蚀的抑制作用.本文采用照相法对全国5个水力侵蚀分区的18个小流域的果园植被覆盖季节变化进行监测,并计算了植被盖度和郁闭度,最后计算果园B值.结果表明:果园郁闭度受人为活动影响小,季节变化呈“几”字形分布.果园的绿色盖度和总盖度因地表下垫面的管理不同而表现出不同的季节变化规律.在林下未清理的果园中,各水力侵蚀分区的绿色盖度呈“几”字形分布;5个水力侵蚀分区中,西北黄土高原区植被总盖度呈“几”字型分布,其余几个分区植被覆盖总盖度呈“一”字形分布,随季节变化不明显.在林下清理的果园中,所有水力侵蚀分区的植被盖度季节变化无规律性.东北黑土区果园B因子最小,平均值为0.0066,西北黄土高原区果园B因子平均值最大,为0.1212,北方土石山区、南方红壤区和西南土石山区果园B因子平均值相差不大,分别为0.0548、0.0627和0.0639.
The biological measure factor (B) can quantitatively measure the effect of vegetation cover on soil erosion.In this paper, the seasonal changes of orchard vegetation cover in 18 small watersheds with 5 hydropower erosion areas in China were monitored by photographic methods, and the vegetation cover and Canopy density, and finally calculated the value of orchard B. The results showed that the orchard canopy density was less affected by anthropogenic activities and the seasonal variation was “” “glyph distribution.” Orchard’s green cover and total cover due to the management of surface underlying surface And showed different seasonal variation laws.In the unprocessed forest under orchard, the green cover of each hydraulic erosion area was distributed in “zhe” shape. Of the five water erosion areas, the total cover of vegetation in the northwestern Loess Plateau The distribution of the vegetation coverage in the remaining several subareas showed a “” glyph distribution, which was not obvious with the seasons. In the undergrowth orchard, all the vegetation cover of the hydropower erosion area The degree of seasonal variation is not regular.Because the northeast black soil orchard B factor is the smallest, with an average of 0.0066, Northwest Loess Plateau orchard B factor average of the largest, 0.1212, Northern Rocky Mountain, Southern Red Soil and Southwest Rocky Mountain Orchard B factor average Poor little 0.0548,0.0627 and 0.0639, respectively.