重金属污染弃耕农田次生演替植物群落组成特征

On the Composition Characteristics of Plant Communities in Abandoned Farmland Heavy Metal Pollution Secondary Succession

为了探讨铜(Cu)镉(Cd)混合污染弃耕农田演替修复能力,同时为筛选耐酸耐Cu、Cd污染的耐受性及富集性强的植物提供依据.2014年冬季至2015年夏季对韶关市曲江区沙溪镇的坝心村和大东村断水弃耕前的农田、藕田、池塘和水渠进行了弃耕演替植物群落结构的调查,分别对共抽取5 000样方样地达到面积5 ha,共鉴定16科38种植物.弃耕后因水源及人为干扰因素导致弃耕田往沼泽湿地与旱地2个方向演替,撂荒隔断水源的水田变为旱地,弃耕后靠近水源的水田演替成沼泽湿地,湿地植物群落以芦苇、芦竹挺水多年生植物为主,构成湿生草本植物阶段演替阶段;旱地植物群落组成与弃耕年限相关,弃耕时间短(5年内)的植物群落以一年生植物为丰富,垂直分布不明显;弃耕时间长(10年内)的以多年生草本为优势,垂直分布呈现多年生丛生草本植物为顶层,底层为苔藓植物和一年生阴生植物.飞蓬、胜红蓟、牛筋草、铺地黍、野葛藤、斑茅及苎麻成为旱地演替的优势植物.

In order to explore the ability of copper （Cu） cadmium （Cd） to contaminate the restoration ability of abandoned farmland, and to provide a basis for screening plants with tolerance to acid and Cu tolerance, Cu pollution and strong enrichment. The investigation of the plant community structure of abandoned farmland, farmland, lotus field, pond and canal was carried out in Shaxin Village and Dadong Village, Shaxi Town, Shaoguan City, from 2014 winter to 2015 summer respectively. The area of the plot reached an area of 5 ha, and a total of 38 species of 16 families were identified, and the waterlogged and man-made disturbances caused the abandoned tillage to become the marsh wetland and dryland. The wetland plant community is mainly composed of perennial plants, such as reed and arundin, which constitute the stage of succession of wet herbaceous plants. The composition of dryland plant community is related to the abandonment period, with the short time of abandonment （less than 5 years） , one-year-old plants take dominance without clear vertical distribution; with the time of abandonment （less than 10 years）, perennial herbaceous plants take dominance, with clear vertical distribution with perennial herbaceous plants as the top and the bryophytes and one-year-old plants grown against the sunlight at the bottom. Flying Pine, Red Thistle, Antelope Grass, Prickly, Pueraria lobata, Ophiopogon japonicus and Ramie become dominant plants in dryland succession.