Location:Home > Engineering science > Environmental Engineering > Study on Soil Organic Matter and Nitrogen Content and Distribution Characteristics of Three Gorges Reservoir Water-Level-Fluctuation Zone
Details
Name

Study on Soil Organic Matter and Nitrogen Content and Distribution Characteristics of Three Gorges Reservoir Water-Level-Fluctuation Zone

Downloads: []
Author
Tutor: WangKunPing
School: Chongqing University
Course: Environmental Engineering
Keywords: Three Gorges Reservoir,Water-Level-Fluctuation Zone,organic matter,Nitrogen
CLC: X833
Type: Master's thesis
Year:  2012
Facebook Google+ Email Gmail Evernote LinkedIn Twitter Addthis

not access Image Error Other errors

Abstract:
After Three Gorges reservoir impoundment, the near-shore land became a specialecosystem that was alternately affected by land and water. In recent years, theecological environment of Three Gorges reservoir was becoming worse and worse, suchas pollution of coastal water and algal blooms. So the affect of water-level-fluctuationzone (WLFZ) soil to water can not be ignored. The14sampling points investigationwas carried out at Chongqing section of three gorges reservoir area on April2010, July2010, September2010, April2011, June2011and September2011. The soil organicmatter and nitrogen content were analyzed. The conclusion is as follows:1) The main soil types of three gorges reservoir WLFZ were purple soil, yellowsoil and alluvial aquic soil. Soil pHs mainly were neuter and weak alkali. Soil EH isbetween-75.00mV and81.20mV, so most of the soils were in an anaerobic environment.2) The mean value of soil organic matter content in the study area is12.31¡À5.20g/kg. There was no significant difference between different type soils. The YangtzeRiver tributary sampling sites organic matter content (12.90¡À5.41g/kg) was higher thanthe Yangtze River trunk stream sampling sites organic matter content (10.84¡À4.40g/kg).Three gorges reservoir water storage led to the increasing of soil organic matter contentand the decreasing of soil organic matter content variation. During the submergedperiod, soil organic matter content increased2.77g/kg while the variation decreasedfrom42.5%to39.7%. At2010dry period soil organic matter content decreased whileincreased at2011dry period. The WLFZ soil organic matter content is greater thannon-submerged soils.3) The mean value of soil total nitrogen content in the study area is1.221¡À0.378g/kg. There was no significant difference between different type soil. The YangtzeRiver tributary sampling sites total nitrogen content (1.220¡À0.304g/kg) was higher thanthe Yangtze River trunk stream sampling sites organic matter content (1.134¡À0.301g/kg).Three gorges reservoir water storage led to the decreasing of soil total nitrogen contentand the variation. During the submerged period, soil total nitrogen content decreased0.257g/kg while the variation decreased from46.4%to24.6%. At2010dry period soiltotal nitrogen content increased while decreased at2011dry period. The differences oftotal nitrogen content between WLFZ soils and non-submerged soils were very small. 4) Guangyangdao tributary soil transformable nitrogen content abided by thefollowing order: WAEF-N> OSF-N> IMOF-N> IEF-N. Other basins soil transformablenitrogen content abided by the following order: OSF-N> WAEF-N> IMOF-N> IEF-N.There was not a significant difference among the various soil transformable nitrogencontents. Transformable nitrogen content of the three type soils are OSF-N> WAEF-N>IMOF-N> IEF-N. Soil non-transformable nitrogen ratio (63.7%) is higher thantransformable nitrogen ratio (36.3%). OSF-N and WAEF-N are two main forms oftransformable nitrogen, accounting for44.2%and36.3%respectively. There was not asignificant difference between WLFZ soil transformable nitrogen content and non-submerged soils.5) Different type soils and different basin soils were analyzed. The results showthat WLFZ soils presented to be "carbon sink" and "nitrogen source" during submergedperiod. Soil organic matter and nitrogen content were quite different from each otherbetween two dry periods. WLFZ soils presented to be "carbon source" and "nitrogensink" at2010dry period while are "carbon sink" and "nitrogen source" at2011dryperiod. The reason of the differences between the two dry periods may be due to thesubmerged time increased and dry time reduced of soil samples of September2011.Pearson correlation analysis was used to see the correlations of organic matter, nitrogenand chemical properties of soil. The results showed that the soil physical and chemicalproperties had no correlation with carbon and nitrogen content, that was mainly becauseof complicated cases of soil carbon and nitrogen input, output, transformation and otherfactors.This work was sponsored by the subject of ¡°Research on the characteristics of thepollution load and the impact on water environment for the WLFZ¡± of Major NationalWater Special Project (2009ZX07104-003-02).
Related Dissertations
Last updated
Sponsored Links
Home |About Us| Contact Us| Feedback| Privacy | copyright | Back to top