Studies On The Nitrogen Transform And Reducing Nitrogen Loss During Composting

Aerobic composting is an important way to transform solid organic wastes to high quality organic fertilizer. It not only can solve the environment pollution of large-size livestock husbandry, but also have importance function in developing organic fertilizer, maintaining and increasing soil fertility, stimulating continues development of Agriculture. Whereas rate of nitrogen losing during composting has been high to be 50%. It is important significant study how to reduce nitrogen loss and to enhance the organic fertilizer nutrient.Opening static composting test of natural ventilation with the ratio of C/N 12.4, 17.4, 31.2, 35.2, Closing static composting test of forced aerated with the ratio of C/N 17.8, 23.6, 26.0, 33.7, 36.2 and a large-scale composting with the ratio of C/N 20.64 using poultry manure and agriculture waste as raw composting material was conducted to quantify various kinds of nitrogen form transform and lose way at different composting stage. The results indicate that low ratio of C/N in the process of composting make total absolute N present a downward trend, but high ratio of C/N have upward trend; The NH4-N and Org-N in Composting course have remarkable change. NO3-N will produce on later stage of composting course, and have vary change trend in different composting mode; The loss way of N is volatile of NH3 which come from NH4-N, the stage of increasing temperature and high temperature stage of composting is the major losing period and will be a well period to reduce the losing of N.The some fixation materials selected of reducing N loss in composting file have be tested including sulfate, chloride and compound substance with magnesium hydroxide and phosphate acid. About adding quantity and rate and mode of fixation materials has been studied through the simulating composting test under basic parameter. Magnesium sulfate (3.9%), earthworm manure (7.8%) and peat (9.8%) were suitable to reduce N loss in composting pile with over 70% of N fixation rate, at the same time, the elements of those materials can increase nutrient content of compost production. Serials of mixture materials with magnesium hydroxide and phosphate acid according to rates have high effect of fixation of N to reach over 85% of N fixation rate on synthesizing MgNH4PO4 which produce a new org-inorganic compound fertilizer.