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The Research of Existing Characteristics and Chemical Stability of Typical Soil Organic Matter in Chongqing

Author: YangYi
Tutor: WeiShiQiang
School: Southwestern University
Course: Environmental Engineering
Keywords: soil organic matter diameter Classification density fractionation C02 emissions chemical stability
CLC: S158
Type: Master's thesis
Year: 2011
Downloads: 178
Quote: 0
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Abstract


Soil organic matter storage shed of soil Nutrient, has an important role in improving soil structure and the soil temperature and enhanced water and fertilizer, is a important indicator of measuring soil fertility. simultaneity, combinated with pesticides, heavy metals and affect the biological activity of these pollutants and migration-leaching conditions. Soil is an important global carbon storage vault, in the form of organic matter carbon account up 1500Pg, is 3 times of the atmosphere. The carbon’s cycling and turnover is closely linked with global climate changes and ecological environment. The cycle and turnover of soil organic matter is great significant important to food and environmental safety. Therefore, soil organic matter is both the focus concerns for sustainable development of agriculture and the important requirement for protection of ecological environment safetySoil organic matter not only exist differences in the quantity.but also vary in composition and properties, Thus,it is significant different in regulation of soil fertility, pollution-purification ability and in the aspects of the role as soil carbon storage(carbon sinks). The turnover of soil organic matter involves a series of complex biotransformation processes.On one side, Foreign organic substances Continue to enter the soil, form stable soil Carbon by Soil degradation and transformation;on the other side, the original organic matter continue to leave the soil as a result of microbial decomposition and mineralization. The stability of organic matter in soil varies greatly from its cycling and turnover rate. In recent years, stable carbon isotope analysis assessed the degradation extent of soil organic matter, carbon-turnover in soil and studies history of C3/C4 vegetation change in the application is becoming more and more mature, but the method is a long period, consuming large, and can only mark the average short lifetime of soil organic matter, simultaneity.Low-energy ion radiation would also cause potential harm to human health, making it certain restrictions on the applicationIn this study, by chemical oxidation comparing chemical stability in four types of soil organic matter in Chongqing at the different density. different particle size and different forms is used to analysis the correlation between the soil basic properties and chemical stability of soil organic matters, analysis and comparison antioxygenic property in different densities of particles of the soil organic matter, labile organic matter in different particle size, different forms of chemical stability of soil organic matter, provide a scientific basis for the management of soil organic matter and assessment of soil carbon sinks.The results suggested that as follows:(1) methods of potassium permanganate for assessment of organic matter chemical stability should be in a certain range of concentrations, which oxidized apt-oxidized components in soils while KMnO4 concentrations was less than 0.1 mol.L-1. Meanwhile, KMnO4 concentration was 0.3mol.L-1 could reflect the differences of anti-oxidization of organic matters among various soils. In addition, the chemical stability of organic matters from six soils followed the order:humus layer of yellow soil in JinYun mountain>purple alluvial soil> alluvial soil of JiaLing riverside>grey-brown alluvial soil> mineral yellow mud> purple soil of grey-brown-purple mud; (2) chemical stability was found have significant correlationship with pH, content of organic matters, total nitrogen, available nitrogen and available phosphorus;Method of hydrogen peroxide could be used to better reflect the anti-oxidation capability of organic matters in different density fractions of soils, which showed the capacities of grey-brown alluvial soil, purple alluvial soil and mineral yellow mud increased with acidity increasing, thereinto AOC of low fraction organic matter (LFOM) was higher than of heavy fraction organic matter (HFOM) in grey-brown alluvial soil and purple alluvial soil, however, this similar results were not observed between LFOM and HFOM in mineral yellow mud and humus layer of yellow soil in JinYun mountain. In addition, oxidation rate of organic matter in farmland soil was found to have a consecutive increase with acidity increasing, however the rate of organic matter from forest soil, which showed less than 50%.The research of labile organic matter indifferent size of soil particles discovered that:(1) the total soil organic matter and labile organic matter have a significant difference among different types of soils, with those of JinYun mountain being the highest; the percentage of labile organic matter accounted for total soil organic matter followed the order:mineral yellow mud> humus layer of yellow soil in JinYun mountain> grey-brown alluvial soil> purple alluvial soil; (2) labile organic matter is the highest in 0.25-0.5mm sized aggregates in grey-brown alluvial soil and purple alluvial soil; labile organic matter is almost the same in different sized aggregates in mineral yellow mud; labile organic matter is the highest in 0.5-1mm sized aggregates in humus layer of yellow soil in JinYun mountain (3) the distribution of labile organic matter in different-sized aggregates of soils is dominantly affected by their mass distributions in the soils.The study of the content of Ca-SOC and Fe(AI)-SOC suggested that Ca-SOC and Fe(AI)-SOC was found have significant positive correlationship with chemical stability while KMnO4 concentrations was 0.05mol.L-1(Rca=0.963, RFe=0.956, p<0.01);Fe(AI)-SOC was found have positive correlationship with chemical stability while KMnO4 concentrations was O.1mol.L-1 (RFe=-0.828, p<0.05);while KMnO4 concentrations was O.3mol.L-1, the relationship between Ca-SOC, Fe(AI)-SOC and chemical stability was manifest negative,it Showed that Ca-SOC and Fe(AI)-SOC have less antioxidant capacity than soil organic carbon with alumino-silicate clay minerals.The Simulation of concentration of CO2 emission form four typical soil organic matter suggested that concentrations of CO2 emissions from grey-brown alluvial soil,purple alluvial soil,mineral yellow mud is the largest during the medium term of Culture; but concentrations of CO2 emissions from humus layer of yellow soil in JinYun mountain is the largest during prior period term of Culture; The concentrations of CO2 emissions from grey-brown alluvial soil,purple alluvial soil,mineral yellow mud increase d with the increase of the number of training days,but the reverse was humus layer of yellow soil in JinYun mountain; chemical stability of humus layer of yellow soil in JinYun mountain Less than grey-brown alluvial soil,purple alluvial soil,mineral yellow mud purple alluvial soil.

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CLC: > Agricultural Sciences > Agriculture as the foundation of science > Soil > Soil fertility (soil fertility )
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