Dynamics Of Physicochemical Properties And Enzyme Activities In The Manure Compost Process

At present,composting is an efficient and sustainable way for solid wastes utilization,get widespread attention in domestic and overseas.The domestic and foreign scholars have been paying attention to the research of the physical,chemical and biological changes during the composting process.At present,researchers are mostly confined to the laboratory simulation test or outdoor small piles test,while little for the material changes of organic fertilizer production.We want to reveal the changes of the material’s physical and chemical property and the dynamic changes of enzyme activity in the organic fertilizer production by the observation of the organic fertilizer production process.Furthermore,we can offer reference to other research of exploring the indices in the process of organic fertilizer production.In the actual production process of organic fertilizer,compost pile temperature increased firstly and then decreased.The beginning of the compost pile temperature was 40°C,higher than ambient temperature.The initial water content of three compost piles were different(from 53%to 64%).The water content of the end of the organic fertilizer composting was distributed from 20%to 30%.Water content had significant relationships with ammonia nitrogen content,organic carbon content,urease activity and nitrate reductase activity.There was no significant change of pH in the composting process(unstable fluctuations from 7.6 to 8.3).In the warming period and high temperature period,the organic carbon content of the three piles decreased fast,but three piles respectively increased in one day(35th day,25th day and 26th day).The content of organic carbon became stable at around 270 g/kg.Ammonia nitrogen content in the composting process had been declining.It is different from the result of the indoor simulation test that there is an increased first and then decreased process.This is because that the compost pile in actual condition was turned frequently and a large amount of ammonia volatilization but no formation of ammonia nitrogen.Nitrate nitrogen was low at the beginning of compost but a significant increase in 5th day and became stable in 12th day.Urease activity and nitrate reductase activity had been declining in the composting process.Urease activity had significant relationships with the content of ammonia nitrogen and organic carbon content and nitrite reductase activity also had significant correlation with moisture content and organic carbon.Nitrate reductase was first increased and then decreased during the composting process.Moisture content,organic carbon content and ammonium nitrogen content in the whol e composting process have been falling.Enzyme activity also decreased as thetrend.The whole composting process is accompanied by the reaction of microbial and material consu mption.So we should give full consideration to the moisture content of material,material p roportion and composting cycle coordination before the compost.