Temperature And Moisture On Soil Humus Formation And Transformation

In this paper, simulating experiment method indoors was used to study the effect of different temperature and water condition on soil humus from the dynamic state perspective. The transformation law with time was learned among the carbon amounts of soil microorganism ,the amounts and state of organic materials, the formation of humus and its chemical and optical properties. The soil microorganism's important effect on formation of every component of humus had been made clear. Then the change law and transformation mechanism of humic acids (HA) and fulvic acids (FA) was discussed and searched during soil humification in different environment condition. All of studies had provided not only theoretical foundation for demonstrating the relationship among the formation and transformation mechanism of soil humus, environment condition and regulating soil fertility, but also new information for Soil Biochemistries' study. The results as follows:After the addition of corn stalk, the carbon value of soil microorganism quantity was high and then decreased with the prolonged incubation time. Low temperature could decrease vitality of microorganism and consumption of soil microorganism carbon quantity and then be in favor of carbon accumulation of microorganism quantity. With the temperature raised, the carbon consumption of microorganism quantity increased with the decomposition speed accelerating and its content decreasing. Increasing soil moisture content could induce fast transformation of soil microorganism carbon quantity with low soil moisture content and decrease vitality of microorganism, finally cause microorganism carbon quantity to decompose lowly and accumulate.The content of soil and water-soluble organic carbon decreased gradually with corn stalk decomposition. Low temperature, excessive high and low moisture content could cause anoxia, so districted movement of microorganism and induce soil organic carbon and then the content of soluble organic carbon increased. The most appropriate decomposition speed of soil organic materials was 25℃-55℃.The optimal moisture content was in a range of 70%-90% of field maintaining water quantity.With temperature increasing, the decomposition and transformation function enhanced. It demonstrated that low temperature could be in favor of the accumulationof HE .With temperature raised, Hu would transform into extractable components and its content would decrease. Being soiled condition could be in favor of decomposition ofHu.High temperature is in favor of the formation of HA but the decomposition of FA. It is showed that temperature and water are the most factors to HE and HA, but they do not effect PQ. Maybe the process of decomposition and formation of HE and HA are complicated, and that is why people are perplexed at the formation order of HA and FA.After the addition of corn stalk, the molecular of HA would became simple. With the corn stalk decomposition continuously, they became complex. At low temperature, the complication of HA was weak, but when temperature was high, would enhance. Being soiled and drought condition would be favorable for the simple ofHA.It was showed that both of temperature and water were the important environment factor which could effect on the formation and transformation of humus. When temperature and water condition was different, the composition and character of humus would be different too.