微生物生理群在猪粪秸秆高温堆肥碳氮转化中的作用

在自制的强制通风静态堆肥反应箱中,猪粪与秸秆以鲜重7∶1的比例进行了堆肥化实验,在堆制的23 d里根据堆温变化分阶段采集堆肥样品,利用MPN法测定了堆料中纤维素分解菌和氮素微生物生理群的数量变化,同时测定了相应的碳、氮含量。结果表明,纤维素分解菌在稳定腐熟阶段较多,对于后期有机碳的降解和腐殖质含量的增大起了很大的作用,在堆制的23 d里,腐殖质增加了2.4%。整个堆制过程中,氨化细菌的数量最大且与氨气释放浓度和铵态氮含量呈显著正相关,都在高温期增加,降温期后减少,氨化细菌的数量在高温期的增加率远高于降温期后的减少率,而铵态氮在高温期的增加率远低于在降温后期的减少率,铵态氮总体上减少了74.1%;亚硝化细菌数量与硝态氮呈正相关;反硝化细菌数量在降温期上升幅度较大,堆制结束时为堆制初期的13倍,且与堆肥中硝态氮含量呈正相关;硝态氮含量增加了87.5%;堆肥后期硝态氮的增加可能与堆肥中存在能进行硝化作用的反硝化细菌有关。固氮菌数量在堆制结束时达堆制初期的2.61倍,主要在降温期增加较多,对堆肥中有机氮的形成起很大作用。

Function of microbial physiological group in carbon and nitrogen transformation during a swine manure-straw compost

Fresh swine manure and wheat straw were mixed at a 7∶1 ratio and then composted in a self-built,static forced-air composting box(90 L).During the period of 23 days,temperature was monitored every day and compost samples were taken at 0,4,17,and 23 d after the start of the experiment.The amounts of cellulose-decomposing microorganism,ammonifiers,nitrifiers,denitrifiers,nitrogen-fixing bacteria were determined with the method of MPN and the concentrations of water-soluble organic carbon,organic carbon,humics,ammonium(NH+4-N),nitrate(NO-3-N),organic N(Org-N) and NH3 were also measured.The results indicated that cellulose-decomposing microbes increased significantly at the stable compost stage and played a significant role in the degradation of carbon and the increase of humics acid.During the period of 23 days,the humics acid concentration increased by 2.4%.Ammonifiers had the greatest amount during the period of 23 days and had a significant positive correlation with the concentrations of NH+4-N and NH3.They all increased at the high temperature period and decreased at the cooling stage of composting.The ammonifiers amount increasing rate at themophilic period was much higher than its reducing rate at the cooling period,while the NH+4-N contents showed the opposite trend and the NH+4-N concentration decreased by 74.1% during the composting.The amount of nitrifying bacteria and denitrifiers all had positive correlation with NO-3-N contents during the composting.The denitrifiers increased significantly at the cooling composting stage and its amount after cooling stage was 13 times higher than its at the initial stage.The NO-3-N concentration increased by 87.5% after composting.The reason of NO-3-N concentration increase might be partly explained by the relation with nrtirfication of denitrifiers.The azotobacter amounts increased 2.61 times during the composting,which had a significant increase in the cooling stage and it played an important role in the forming of org-N.