Abstract: The effects of different distribution format of soil nutrients were analyzed on the aboveground quantitative characteristics of Artemisia scoparia Waldst.et Kitag.community which was uniform in vegetation distribution.The experimental site was divided into plots,then the diammonium phosphate was applied to the plots by two kinds of manners,homogeneous vs.heterogeneous,in spatial distribution of soil nutrients.The results show that plant height and biomass were greater in plots with heterogeneous soil nutrients than those in homogeneous under same fertilization intensity.Plant height was 31.94 cm in heterogeneous plots and 27.41 cm in homogeneous distribution under high fertilization intensity.Plots with fertilization had more biomass yield in comparison with the control.Although the biomass in heterogeneous plots were significantly higher than that in control,the difference between homogeneous plots and control was not significant,which indicate that spatial heterogeneity of soil nutrients could increase the aboveground primary productivity of community to some extent.Plant density was decreased by heterogeneous fertilization,but increased by homogeneous fertilization.Plant density was 121/m² in heterogeneous plots and 291/m² in homogeneous plots.Under the high fertilization intensity,plant community’s diversity index(H) in heterogeneous plots was 0.752 2±0.40,which was greater obviously than homogeneous plots(H=0.4002±0.31) and control(H=0.3147±0.24).Simpson dominance index in heterogeneous plots was 0.484 7±0.20,which was lower than homogeneous fertilization plots(λ=0.8182±0.15) and control(λ=0.8228±0.11).Under same fertilization intensity,heterogeneous distribution of soil nutrients increased the species diversity and evenness and decreased the dominance ratio of community.

Key words: Fertilization, Heterogeneity, Homogeneity, Species diversity

摘要： 选择植被分布较均匀的猪毛蒿(Artemisia scoparia Waldst. et Kitag.)群落作为样地划分小区,在空间呈均匀和异质2种分布方式将(NH₄)₂HPO₄肥料施入小区中,以分析土壤养分的分布方式对群落数量特征的影响。结果表明:同一施肥强度下,肥料在土壤中呈斑块状异质分布比均匀分布更能促进植被的高度和生物量的增加。高施肥强度下,肥料呈异质分布时植被平均高度为31.94 cm,呈均匀分布时为27.41 cm;施肥区植株生物量显著高于CK(P<0.05),而均匀施肥区植株生物量与CK间未达显著水平,说明一定范围内,土壤养分的异质性更能提高群落地上部生产力。异质施肥降低了植株的平均密度,为121株/m²;而均匀施肥提高了植株的平均密度,为291株/m²。异质施肥区植物群落Shannon-wiener(H)指数为0.752 2±0.40,显著高于均匀施肥区和CK(分别为0.400 2±0.31,0.394 7±0.24);Simpson(λ)优势度指数为0.484 7±0.20,显著低于均匀施肥区和CK(分别为0.818 2±0.15,0.822 8±0.11)。并且,同一施肥强度下,土壤养分呈异质分布,可以提高样地植物群落中的物种多样性和均匀度,降低群落的优势度。

关键词: 施肥, 异质性, 均匀性, 物种多样性