The Changes Of Hydrolytic Enzyme Activities During The Straw Composting At High Tempurature And Static State

The compost of agricultural waste materials is the process that under the function of microorganism,the organic matter turn into well-rotted manure by the way of the organic matter being mineralized and humus and harmless.In the process of the function of microorganism,not only massive the nitrogen,phosphorus and potassium compounds that are useful to plant are produced,also new high polymer organic matter---humus is synthesized.Because the process is the reaction of enzyme pressing,this is produced by microorganism,study the changes of enzymes activity is helpful to explain the process and mechanism of composting well and offer important scientific value.The changes of the activity of the cellulose,sucrose,urea enzymes,protein enzyme,temperature,water content,electric conductivity,and pH had been studied during an aeration composting process in a static state using substrate of mixed wheat straw,maize straw and urea with and without adding microorganism agent.Three treatments of adding microorganism agents actived glucose(G+J),adding microorganism agents(J) and without microorganism agents(CK) were made in wheat straw and urea composting process.Two treatments of adding microorganism agents(J) and without microorganism agents(CK) were made in maize straw and urea composting process. The main results are showed as follows:1.The peak value of the cellulose enzyme activity in the treatment of G+J was observed in 9 d,and was earlier than J and CK for 3 d and 6 d,among them the values were 334.37 mg glucose(g.24h)^-1,271.59 mg glucose(g.24h)^-1 and 236.67 mg glucose(g.24h)^-1 respectively during the wheat straw and urea composting process.There was a large variation in trends of cellulose enzyme activity.While during the maize straw and urea composting process,the peak value of the cellulose enzyme activity in the treatment of J was observed in 9 d,and was earlier than CK for 3 d,among them the values were 352.11 mg glucose(g.24h)^-1 and 285.51 mg glucose(g.24h)^-1 respectively.The trend of cellulose enzyme activity adding microorganism agents was the same as that without microorganism agents. 2.The peak value of the sucrose enzyme activity in the treatment of G+J was observed in 9 d,and was earlier than J and CK for 3 d and 6 d,among them the values were 1582.64 mg glucose(g.24h)^-1,1455.18 mg glucose(g.24h)^-1 and 625.06 mg glucose(g.24h)^-1 respectively during the wheat straw and urea composting process.And the peak values of sucrose enzyme activity in the treatments of G+J and J were 2.53 times and 2.33 times than CK,respectively.It represents that adding microorganism agents can enhance the sucrose enzyme activity and accelerate the mineralization of agricultural wastes.While during the maize straw and urea composting process,the trend of sucrose enzyme activity was in accordance with the temperature during the period of 4 d and 12 d,and the sucrose enzyme activity fell with the decrease of temperature.3.The urea enzyme activities of three treatments were lower than 20.00 mg NH₃ (g.24h)^-1 after 23 d during the wheat straw and urea composting process.The average activities of urea enzyme of three treatments were 50.69±26.17 mg NH₃(g.24h)^-1,34.68±7.58 mg NH₃(g.24h)^-1 and 25.20±5.08 mg NH₃(g.24h)^-1,respectively.Adding microorganism agents can enhance the urea enzyme activities.The average urea enzyme activity was (215.50±49.96) mg NH₃(g.24h)^-1 in treatment of J in maize straw and urea composting process,much higher than CK(F=18.73,P＜0.05).It illustrates that adding microorganism agents can enhance the urea enzyme activity and accelerate transformation of amide compounds.4.In the wheat straw and urea composting process,the activities of protein enzyme decreased with rise of temperature in 2 d in three treatments,so,high temperature can restrain protein enzyme activities.The average activities of protein enzyme were(9.63±1.37) NH₂(g.24h)^-1 and(8.38±0.98) NH₂(g.24h)^-1 in treatment of J and CK during maize straw and urea composting process.And the coefficient of variation were 14.23%11.69%,respectively. The reason maybe that maize straw had little raw protein,so it can induce little substrate.5.The highest temperature for G+J,J and CK were 66℃,67.1℃and 59.5℃, respectively.The rank of time for temperature higher than 50℃was:G+J(240 h)＞J(120 h)＞CK(96 h) during the wheat straw and urea composting process.The highest temperature were 73.3℃and 65.9℃for J and CK and the rank of time for temperature higher than 50℃was:＞J(240 h)＞CK(192 h) during the maize straw and urea composting process.Water content decreased in wheat and maize straw and urea composting process.The values of EC were 2.69 ms/cm,2.32 ms/cm and 2.30 ms/cm for three treatments in 12 d during the wheat straw and urea composting process.The value of EC of the treatment adding microbial inoculants was higher than that without microbial inoculants during the maize straw and urea composting process.And the values of EC were 26.59 ms/cm and 23.26 ms/cm.The value of pH increased in 2d,and decreased in 4d,and then on the rise in wheat straw and urea composting process.The same situation was detected in maize and urea composting process. Lower pH values and small range of changes in pH values were founded in two different agricultural materials adding microbial inoculants.