【作者】 李永强；

【导师】 许志信；

【作者基本信息】 内蒙古农业大学 ， 草业科学， 2003， 硕士

【摘要】 本试验分别在内蒙古锡林郭勒盟典型草原带和呼伦贝尔盟草甸草原带对不同撂荒年限的撂荒地植被动态及土壤特性进行了研究，目的是探讨草原区撂荒地植被演替的规律，为撂荒地植被的重建提供理论依据。 在典型草原带和草甸草原带的撂荒地演替过程中，表现出一、二年生杂草、多年生根茎禾草、多年生丛生禾草(或多年生杂类草)各功能群占主导地位依次更替的群落演替序列。随撂荒年限的增加，多年生植物的种类和数量逐渐增加，植物群落功能群构成逐渐丰富，群落间β多样性指数随撂荒时间间隔的增大而逐渐减小。但植被恢复缓慢，撂荒30年仍未达到顶极群落阶段。典型草原撂荒地Shannon-Wiener多样性指数的平均值为1.5481，是天然草地的55％，草甸草原带撂荒地Shannon-Wiener多样性指数的平均值为1.3492，是天然草地的50％。 随撂荒年限的增加，土壤有机质、全氮、碱解氮等主要养分均表现出先降低后增加的趋势；撂荒地有机碳的损失平均达到59.4％；在撂荒地表面0-20cm范围内，0.25-0.05mm粒径的砂粒含量逐渐增加，各撂荒地砂粒平均含量达76.84％，粉粒和粘粒含量逐渐降低，土壤机械组成出现粗化现象。土壤开垦对土壤容重和水分状况也有不同程度的扰动作用。 长远来看，草地开垦经济效益低下，撂荒后又面临土壤养分流失、机械组成粗化、植被恢复缓慢、抗干扰能力弱等诸多生态问题，因此，无论从经济学还是生态学角度，开垦草地得不偿失。更多还原

【Abstract】 Vegetation dynamics and soil characteristics of different period abandoned land was conducted in typical steppe at Xilinguole League and meadow steppe at Hulunbeier League, Inner Mongolia. The results showed:The function community of annual plants, perennial rhizornatous grasses and perennial rosette grasses were appeared at different succession stage of abandoned land in typical steppe and meadow steppe. With the increase of abandoned time, perennial plants increased, the function communities were richer, P diversity index in two communities reduced with abandoned interval, but the vegetation restoration was slow, the land abandoned for 30 years have not got to climax community. The average of Shannon-Wiener diversity index was 1.5481 in typical steppe abandoned land, which was only 55% of natural grassland, while it was 1.3492 in meadow steppe abandoned steppe.The organic matter, total N, hydrolytic N were increased, then reduced with the increase of abandoned time. The loss of organic C got up to 59.4% in abandoned land. In 0-20cm, the sand content of 0.25-0.05mm was increased gradually, the average content of sand in the abandoned land was up to 76.84%, the sand contents of silt and sand was gradually reduced, the soil mechanic compose became coarse. The soil reclamation has different effect upon soil unit weight and water.In the long run, the economy beneficial of grassland claim is lower. The soil nutrition lose, mechanic compose become crude, vegetation restore is slow, the drought resisted ability is poor. Therefore, it is not worth to claim grassland both from economy and ecology point of view.更多还原