垦复干扰对糙花少穗竹秆径分布的影响

Effects of reclaiming disturbance on diameter distribution of Oligostachyum scabriflorum

应用4种分布函数对6个垦复糙花少穗竹林样地全部立竹及其各龄级的秆径分布进行拟合,并以1个未垦复样地为对比,结果表明,各样地拟合效果最好的均是Weibull分布.垦复样地的立竹总体平均秆径和幼龄竹平均秆径均大于未垦复样地.垦复样地的秆径分布峰度值均较大,秆径各径阶分布相对集中而有利于竹林管理.各样地的总体秆径分布偏度均为正值,分布曲线右偏,但垦复样地的幼龄竹秆径分布则为左偏,秆径结构还需进一步调整.各种垦复措施相比,劈山和多次浅翻均在短时间内提高了大径阶立竹的数量,不利于长期地力维持;而浅翻施肥和全锄使立竹秆径偏度为正值且大小适当,是效果较好的垦复措施.

Analysis with 4 kinds of distribution functions on culm diameter distribution of Oligostachyum scabriflorum in 6 reclaimed plots, compared with 1 wild plot showed that Weibell distrbution model was the fittest for all plots. The average culm diameters of total stand bamboos and young bamboos in reclaimed plots were larger than that in wild plot. Larger kurtosis of culm diameters in reclaimed plots meant that the culm diameter grades fastened on the averages and were beneficial to management. Skewness of culm diameters of total stand bamboos in all plots was positive and the distribution curves leaned to right, but the curves of young bamboos leaned to left, which indicated the need of more regulation of culm diameter configuration. Cleaving down the shrubs and digging in surface for several times increased the frequency of larger diameter grade in shot time and were unfavorable to continuable soil fertility. Digging in surface with fertilization and hoeing down the herbs were good reclaiming methods by causing the positive and appropriate values of skewness.