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Effects of Organic Material and Temperature and Soil Moisture on Organic Carbon Decomposition of Black Soil

Author: ZhangLei
Tutor: Wei
School: Northeast Agricultural University
Course: Crop Cultivation and Farming System
Keywords: Black soil Soil organic carbon decomposition Organic material temperature Soil moisture
CLC: S158
Type: Master's thesis
Year: 2004
Downloads: 245
Quote: 1
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Abstract

The incubating experiments were conducted in laboratory to study the effects of organic material on soil organic carbon decomposition in black soil with different organic carbon content. To quantitatively investigate the relationship of temperature and soil moisture with soil organic carbon decomposition, CO2 released rate and the change of soil organic carbon content were measured from three soils of different soil organic carbon content under the condition of different temperature and soil moisture. The result showed: CO2 released rate from the soil with organic material was obvious increasing, and the increasing range of 5% and 3% treatment was much higher than that of 2% and 1% treatment. The increase of CO2 released rate was fast at the beginning and fluctuation was also significant, becoming stable at the later stage. The relatively value increased with the amount of organic material and the soil organic carbon content, namely samples 6,5,4,2 adn 1.The value of sample 3 was much higher than the others’ because its physical and chemical properties were different. The quantity of soil organic carbon after the incubation was related to the amount of organic material applied to the soil from samples 1 to 5, but not sample 6. Complex quantity and additional complex quantity of every treatment were all increasing with the raising of the amount of applied organic material from samples 1 to 5. The two values of sample 6 were decreasing. The proper quantity applied organic material into soil was separately 2%、3%、2%、5%、2% level from sample 1 to sample 5. The organic material applied into soil at this level not only transferred organic material into soil nutrition but also decreased the amount of CO2 released from the decomposition of organic material. The proper quantity of applied organic material into the soil was at the 5% level if sample 6 would be exploited into agricultural soil, because it would control the decreasing tendency of soil organic carbon at this level.Under the same moist condition, CO2 released rate was high at the beginning （1～20d）, and the relatively value was 35℃, 25℃,15℃ and 5℃. CO2 released rate was gradually became stable with the incubation time (>20d). Under the same temperature condition, CO2 released rate of every moist treatment were all high at the beginning and gradually declined. The value was positive related to the moist content（30%～90%WHC）when the value was stable. And under the same temperature and moist condition, the relatively value of CO2 released rate was increasing with the soil organic carbon content. <WP=10>Complex organic carbon content was declining with the increasing of soil moisture（30%～90%WHC）at 5℃ and 15℃ in low organic carbon content, and it was much higher than others’ with 75%WHC at 25℃ and 35℃. Complex organic carbon content was declining with the increasing of soil moisture（30%～90%WHC）at 5℃ and 25℃ with middle organic carbon, and it was much higher than others’ with 60%WHC at 15℃ and 35℃. It was advantageous to increase the complex organic carbon content with ≤75%WHC at 5℃ with high organic carbon; The complex organic carbon content was different with soil moisture when the temperature was ≥15℃.The interaction of temperature and soil moisture conformed to the function: .The decisive coefficient was very significant and it conformed to the practice very well. It could be shown by the analysis faction: the quantity of CO2 released from soil would rise with increasing temperature and soil moisture（30%～90%WHC）. Under certain condition, it would forecast the soil organic carbon decomposition with the function. Graduate student：Zhang Lei Supervisor：Prof．Wei Shi Major：Crop Science

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