Abstract

In order to discuss the effect of soil fertility on components transformation and energy change of corn stalk during decomposition, carborundum tube was used to study the decomposition of corn stalk buried in different soils with high, medium and low fertility for 480 days. The decomposition rate and change of energy state of corn stalk were revealed. The results showed that the fractions of alcohol-benzene soluble and water soluble decreased in the decomposition process. The concentration of semi cellulose and cellulose increased firstly and then decreased. However, the concentration of lignin increased. The change of energetic state of corn stalk throughout the whole process could be divided into three stages such as fluctuating stage, decreasing stage and stable stage. Totally, the humification was a process of energy release and the relationship of combustion heat and components of corn stalk could be expressed by linear regression. For 480 days of decomposition, the decomposition rate was highest in soil with medium fertility and lowest in soil with low fertility among three type of fertility. The decomposition of water soluble factions and lignin were promoted in medium fertile soil. However, alcohol-benzene soluble fractions, and semi cellulose and cellulose fractions were decayed accelerated in soil with high fertility. Furthermore, more humic substance was formed and energy state of decayed corn stalk was high in soil with high fertility. 
 
Key words: Corn stalk, energetic state, decomposition rate, soil fertility.