土壤酸化对农田杂草群落组成的影响

为了探究土壤酸化对农田杂草群落多样性影响,选取安徽农业大学大杨镇高新技术农业园实验区,通过定位土壤酸化实验,采用随机区组设计和样方法,对不同酸化土壤(pH=6.8、6.3、5.5、4.6,对照pH=7.2)处理下农田杂草的植物种类、高度、密度和频度等指标进行了测量与分析.结果 表明:(1)实验区农田内共有杂草11科、16属、19种,禾本科杂草优势度随着土壤酸化程度增加而增加,荔枝草(Saluia plebeiaR.Br)和红蓼(Polygonum orientale L)等非禾本科杂草数量随土壤酸化程度下降而减少.(2)与对照区相比,农田杂草群落Shannon-Wiener多样性指数、Simpson多样性指数、Margalef物种丰富度指数和Pielou均匀度指数随土壤酸化程度增加均显著降低(P＜0.05).(3)对照区域(pH=7.2处理条件)与其他酸化处理的杂草群落Shannon-Wiener多样性指数差异极显著(P＜0.01).(4)pH=6.8和6.3的处理与pH=5.5和4.6的处理间杂草科、属、种的组成差异显著,相似性低,酸化严重的区域间(pH=5.5与DH=4.6的处理)杂草物种组成相似性更高,相似度达0.67.可见,土壤酸化对农田杂草群落组成具有明显影响.

Effects of soil acidification on weed community composition in farmland

Soil acidification affects plant species composition and diversity of weed communities in farmlands. In this study, an in-situ experiment with randomized group design and sample method was carried out in the High-tech Agricultural Garden at Yang Town, Anhui Agricultural University to examine the differences in species richness, density, and dominance of weeds as well as other species diversity indices under different levels of soil acidification treatments (with soil pH values being manipulated to be 4.5, 5.5, 6.3 and 6.8) compared to the control (pH=7.2). The results showed that:(1) There are 19 weed species belonging to 16 genera of 11 families across different acidification treatments, the dominance of grass weeds increased with the increase of soil acidification, while the number of non-grass weeds such as Saluia plebeia R. Br and Polygonum orientale L. decreased with the decrease of soil acidity.(2) The Shannon-Wiener diversity index, Simpson dominance index, Pielou evenness index and Margalef richness index of the farmland weed community all decreased gradually with the increase of acidification degree, and the poundage differences were significant (P<0.05).(3) In the control area (pH=7.2 treatment conditions), the diversity index of Shannon-Wiener community was significantly different from that of other acidified weed communities (P<0.01). (3) The composition of weed families, genera and species was significantly different between the treatments with pH=6.8 and 6.3 and the treatments with pH=5.5 and 4.6, with low similarity. The composition of weed species was more similar between the regions with severe acidification (pH=5.5 and pH=4.6), with a similarity of 0.67. So, soil acidification has obvious effect on weed community composition in farmland.