Dissertation > Excellent graduate degree dissertation topics show

Soil Enzymatic Activity in Different Grassland Types on the Western Slopes of the Helan Mountains, China

Author: QinYan
Tutor: FuHua
School: Lanzhou University
Course: Grassland
Keywords: Grassland type Soil enzymatic activity Environmental factor Seasonal variation Exclosure practice
CLC: S812.2
Type: Master's thesis
Year: 2007
Downloads: 215
Quote: 6
Read: Download Dissertation

Abstract


Soil enzymatic activity is one of the most important indexes of biological activities in the grassland ecosystem. In this study, we conducted different grassland types at different altitudes along Helan mountain range, in Alxa, Inner Mongolia, China. On the basis of field investigation and laboratory analysis, we studied the distribution characteristics of soil urease, saccharase, alkaline phosphatase and catalase activities among the different grassland types. Furthermore, the relationship between soil enzymatic activities and soil properties, vegetation characteristics, and climatic factors, and the effects of seasonal change and exclosure practice on soil enzymatic activities were investigated in this paper. The results of this study are shown as follows:（1） The soil enzymatic activities declines with decreasing altitude and followed by the order: alpine meadow> mountainous steppe> desert steppe> steppe desert, which is significantly different in the 0-10cm layer. The variation ranges of soil urease, saccharase, alkaline phosphatase and catalase activities among different grassland types are in 0.01-0.37 mg NH4-N g-1 soil. 3h-1、3.90-99.29 mg glucose g-1 soil 24h-1、0.04-1.48 mg P. g-1 soil 12h-1 and 1.44-5.66 ml KMnO4. g-1 soil, respectively. The soil enzymatic activities are gradually reduced following the soil vertical section.（2） The four kinds of soil enzymatic activities were all correlated with annual average temperature, rainfall, plant cover, plant productivity, soil microbial biomass carbon and nitrogen, organic carbon content, total nitrogen, water content, pH. Soil enzymatic activities preferably reflect the soil and vegetation conditions. They can be used as the biological indicators of the grassland degradation degree in the study region. Stepwise regression analysis showed that soil microbial biomass carbon and rainfall were the key factors affecting soil enzymatic activities in the study region.（3） Results showed that it was significantly different among the four kinds of soil enzymatic activities in mountainous steppe, desert steppe and steppe desert. Soil urease activity probably was more sensitive to temperature fluctuation, and it reached the highest in July; Soil saccharase activity continuously went up from April to September, and it reached the highest at the time of good hydrothermal condition in September. Soil alkaline phosphatase and catalase activities showed a decreasing trend in mountainous steppe, but an increasing trend in steppe desert.（4） Soil urease was obviously affected by grazing and exclosure. By exclosure practice for 5 years, soil urease activity has increased by 22.5% at mountainous steppe. So soil urease maybe used as a sensitive indicator of the soil rescovery about degenerated grassland. Comparatively, the effects of grazing and exclosure on soil alkaline phosphatase and catalase were not obvious in this study.

Related Dissertations

  1. The Soil Carbon Pool and Soil Respiration during Natural Succession of Mid-subtropical Evergreen Broadleaved Forest,S714
  2. Studies on Reproductive Biology of Mactra Chinensis and Meretrix Meretrix,S917.4
  3. The Research of Six Different Zenia Insignis Chun of Photosynthesis,S792.99
  4. The Seasonal Evolution of CO2 Source/ sink between Autumn and Winter in Jiaozhou Bay,P734.22
  5. Antarctic Ozone and Vertical Structure of Atmosphere,P421.33
  6. The Influencing Study of Environmental Factors on Freshwater Algae Growth in Yellow River,X173
  7. Forecasting of Fishing Ground for Ablacore (Thunnus Alalunga) in the South Pacific Ocean,S931
  8. The Speciation, Levels and Potential Impacted Factors of Atmospheric Mercury in Hefei, Central China,X51
  9. Study on Fine Root Dynamics of Caragana Korskinskii Seedlings in Loess Plateau Area, Northwest Shanxi,S793.3
  10. Relationship between Soil Respiration and Environmental Factors under Different Land Use Conditions,S714
  11. The Study of the Seasonal Variation Characteristic of the Atmospheric Aerosol and Its Chemical Composition in Guiyang City,X513
  12. Numerical Simulation of the Effect of the Sea Level Variation on Tidal Wave in the East China Sea,P731.23
  13. Distribution Characteristics of Biogenic Elements in the Yellow Sea and Comparison of Properties between the Southern and Northern Yellow Sea Cold Water Masses,P731.1
  14. Seasonal Variation of Gut Cyanophyta Contents and Liver GST Expression of Four Freshwater Fishes in Tropical Xiangang Reservoir (Huizhou, China),S917.4
  15. 3S-based Research on the Grassland Resources of Shuluun Huh Banner,Q948.1
  16. The Study of Benthic Algae in Xinghai Bay, Dalian,Q948
  17. Effects of Different Environmental and Biological Factors on the Growth and Toxin Production of Chattonella Marina,X55
  18. Leaf Water Potential of Spring Wheat and Field Pea under Different Tillage Practices and Their Relationship with Environmental Factors,S643.3
  19. The Dynamic Studies on Grassland Vegetation Types and Characteristic in Etuokeqian Banner,S812
  20. Study on Influence of Seminal Germination of Four Psammophytes about Environmental Factors,S718.4
  21. Study on Tree Canopy Environmental Factors and Physiological Changes of Kiyomi Tangor Trees Covered by Polyethylene Film in Winter,S666.4

CLC: > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > General Animal Science > Grassland Science,prairie school > Grassland soil science
© 2012 www.DissertationTopic.Net  Mobile