Dynamics of organic fractions of cow manure plus wheat straw during decomposition with microbial inoculation.

More than 4 billion tons of livestock and poultry manure were discharged annually at present in China which has became a serious threat to the environment.The production of organic fertilizer through composting of the manure in the present of straw is an effective method for handling livestock waste.The objective of this study was to investigate changes in the organic fractions in cow manure-wheat straw com-post during decomposition with and without microbial inoculation.The experiment included three ratios of cow manure to wheat straw:100∶0,75∶25,and 50∶50.These mixtures were inoculated with efficient cellulose-lignin degrading bacteria,and uninoculated samples were used as control.The decomposition lasted 28 days.The results showed that the concentration of the alcohol soluble fraction decreased gradually dur-ing decomposition,whereas the concentration of the water soluble fraction increased during the first 14 days and then decreased.Semi-cellu-lose and cellulose concentrations fluctuated but decreased slightly across time,whereas the lignin concentrations increased.There was a drop in the concentration of total organic carbon(TOC)and a rise in the humic substance carbon to TOC ratio.The humic acid to fulvic acid(H∶ F)ratio increased across time,but it was always less than 1.0,suggesting that fulvic acid was more than humic acid during humification pro-cess.Addition of wheat straw to manure increased the accumulation of lignin,and a high proportion of cow manure in the mixture was benefi-cial to the formation of humic substances;inoculation with microorganism resulted in faster decomposition of organic fractions and more for-mation of humic substances.