节点文献
陕西吴起退耕地土壤种子库与地上植被研究
Soil Seed Banks and Aboveground Vegetation of Rehabilitated Farmland in Shannxi Province
【作者】 朱文德；
【导师】 魏天兴；
【作者基本信息】 北京林业大学 ， 自然地理学， 2011， 硕士
【摘要】 本研究以黄土高原北部水蚀风蚀交错区陕西吴起县典型退耕地作为研究对象,以不同退耕年限、不同坡向的退耕地作为研究样地,通过对退耕年限分别为0年(农地)、2年、3年、8年、9年、12年(此样地分别选取阴坡和阳坡作为对比研究)、20年和30年的退耕样地的地上植被状况和土壤种子库进行野外实地调查、取样和室内萌发实验,通过对土壤种子库基本特征、地上植被特征的比较研究分析,得到以下结果：(1)该研究区样地土壤种子库种子萌发数量的时间分布格局并非随着退耕年限的增加呈上升趋势,而是呈先增大后减小的峰值变化,密度值变动于467.0±34.4～4283.0±312.2粒/m2之间,其中退耕年限为8年和9年样地的土壤种子库密度最大。(2)在以上不同退耕年限样地的土壤种子库萌发土实验中,0～5cm土层中可萌发种子密度变动于367.0±36.0～2833.0±224.0粒/m2之间,5～10cm土层的土壤种子库密度变动于100.0±14.9～1450.0±104.2粒/m2之间,0～5cm土层的土壤种子库密度是5～10cm土层的2～3倍。(3)研究区土壤种子库可萌发种子的植物组成以双子叶植物占多数,其种子的萌发数量平均为1136粒/m2,而单子叶植物种子萌发数量为713粒/m2,仅占种子萌发总数的38.5%。(4)在地上植被中共统计到6科15属的25种植物,其中主要植物物种为禾本科植物(7种)和菊科植物(7种),豆科植物(4种)、蔷薇科植物(5种)次之；从植物的生活型分析,多年生草本植物出现的比例最高,半灌木植物比例次之,一、二年生草本植物的比例则最低。研究区退耕地土壤种子库中主要以铁杆蒿、达呼里胡枝子、针茅、赖草等一些演替前期的物种为主。土壤种子库和地上植被均无木本出现,因此,要加快研究区退耕地植被恢复的进程,应适当引进一些演替后期物种以缩短恢复和演替时间,在该地区进行植被重建过程中,需要人为加入建群树种种源,促进黄土高原北部水蚀风蚀交错区的植被恢复。
【Abstract】 In this study, typically rehabilitated farmland in wind erosion crisscross region of Shaanxi Wuqi is selected as research subjects in northern Loess Plateau. The study was conducted on the farmland in different years and aspects, through the years were 0 of rehabilitated farmland (agricultural land),2,3,8, 9,12 (this kind of shady and sunny places were selected as the comparative study),20 and 30 years of rehabilitated farmland plots on the ground vegetation and soil seed bank for the field site survey, sampling and laboratory germination experiments on the basic characteristics of the soil seed bank, aboveground vegetation.characteristics and comparative similarity analysis, the preliminary results are showed below:(1) The seed germination of soil seed bank distribution pattern in the study area is not rising with the years of rehabilitated farmland, but at first increased and then decreased peak trend, density changes in 467.0±34.4～4283.0±312.2 grains/m2, which is the highest density of soil seed bank in rehabilitated 8 and 9 years.(2) In the experiment, germinable seed density in 0～5cm soil changes between 367.0±36.0 and 2833.0±224.0 grains/m2; 5～10cm soil layer changes between 100.0±14.9 and 1450.0±104.2 grains/m2. Soil seed bank density of 0-5cm layer is about 2 times than that of 5～10cm.(3) The soil seed bank germination of plants are formed by the majority of dicotyledonous plants, the number of seed germination 1136 grains/m2, while the number of monocot plant seed germination for the 713 grains/m2, only account 38.5% of the total number.(4) Statistics on the ground vegetation in the CPC are 6 families and 15 genera,25 species of plants, mainly are Gramineae plant species (7), Compositae (7 species) and legumes (4 species), Rosaceae (5) are the second one; From the type of plant life, the highest proportion of perennial grasses appeared, followed by half the proportion of shrub plants, the lowest proportion is biennial herbs.The soil seed bank are mainly Artemisia gmelinii, Lespedeza, Stipa grandis, Leymus and other early successional species in rehabilitated farmland. There are both no woody plants in the soil seed bank and abovegroud. Therefore, to speed up the research area vegetation restoration process, it should be properly introduce some later successional species to shorten recovery and succession time. In the revegetation process, planting colonization provenance artificially to promote the vegetation restoration of water erosion of wind erosion crisscross area in the north loess plateau.