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Northwest University of Science and Technology (2003)

Soil Quality Evolvement Mechanism in the Process of Vegetation Restoration in Semiarid Hilly Region

Liu Meng Yun

Titre : Soil Quality Evolvement Mechanism in the Process of Vegetation Restoration in Semiarid Hilly Region

Auteur : Liu Meng Yun

Grade : Master’s Theses 2003

University : Northwest University of Science and Technology

Résumé
In this study, Ningxia yellow test area, the application of restoration ecology, soil science and related disciplines in the basic theory in Southern Ningxia Mountain (yellow test area) in Ningxia different land use types on soil quality and its occurrence, The development and evolution of the system. Through field investigation, soil sample collection and laboratory analysis, a comprehensive and systematic study of Ningxia yellow test area of ??soil particles, reunion performance, tight situation, conventional and chemical properties and soil enzyme activities, the initial establishment of soil quality evaluation system, in order to establish effective type of vegetation cover to improve soil quality and rational use of land resources to provide the basis for decision making. A different land use patterns of soil physical properties varied significantly. Soil bulk density : surface orchard gt ; agricultural land gt ; natural grass gt ; artificial grass gt ; shrub land ; shrub land with the increase of planting years and gradually reduce the total porosity is gradually increased. Of soil particles : sand content of the shrub land than other land types ; shrub land with the extension of the planting years, the clay content tend to increase soil texture by the sand gradually becomes sticky ; natural grassland silt, clay content than other land high-use types, the strong improvement of the role of soil particles ; clay content of agricultural land subsurface than the surface, reflecting the soil erosion to reduce the surface clay soil particles to coarse ossification. Total soil aggregates : natural grassland gt ; shrub land gt ; orchard gt ; agricultural land gt ; artificial grass ; for different types of land, shrub land and natural grassland conducive to the formation of large particle aggregates, while the agricultural land smaller the particle size of the aggregates formed by the artificial meadow and orchard. Soil micro-aggregates : shrub land and grassland soils 1-0.01 mm micro-higher aggregate content, and orchard low ; shrubs and grass for the formation of soil micro-structure ; orchard surface microstructure of water-stable soil the worst , shrubs and artificial grass. (2) the different land use patterns of soil chemical properties significantly different. Soil organic matter : natural grass, a higher content of shrub land and agricultural land, orchards minimum ; shrub land for the improving effect of the soil than other land use types significantly increased the organic matter content, but also increase the amount of effective soil nitrogen supply, followed by natural grass and artificial turf, and the orchard is not only less organic matter content, vegetation can provide an effective nitrogen amount at least. Soil nitrogen : shrub land followed by artificial grassland and agricultural land, orchards minimum ; shrub land soil nitrogen accumulation function ; improving the results of the natural grass on total soil nitrogen is relatively stable. Soil available P : surface orchard gt ; agricultural land gt ; natural grass gt ; artificial grass = shrub land ; agricultural land and orchards in the section changes more violent ; natural grassland relative ease. lt ; WP = 5 gt ; soil potassium : agricultural land and orchards with higher levels of artificial grass, followed by the lowest shrub land ; shrub land with the prolongation of the recovery phase, and available K increased ; the orchard trend contrast . Cation exchange capacity : shrub land, artificial grass and natural grass CEC content higher than agricultural land, orchards minimum ; shrub land with the prolongation of recovery time, cation exchange capacity gradually increase. The soil mineralogical composition : the development of a high degree of natural grassland and agricultural land, the process of soil formation to a degree of desilication, rich Al-Fe phenomenon. (3) soil biological activity is also significantly different. Natural grassland soil enzyme activity, followed by shrubs, woodland and pasture, orchards and agricultural land, low ; long year of shrub land soil enzyme activity is higher than a year short of orchards changes are not large. The initial establishment of soil quality evaluation system, come to change the order of the tested soil quality index shrub woodland gt ; natural grass gt ; agricultural land gt ; artificial grass gt ; orchards, shrub land recovery of soil amelioration of the most significant followed by natural grassland, and orchard on Soil poor.

Présentation (Dissertation topics)

Page publiée le 7 octobre 2014, mise à jour le 21 septembre 2017