不同碳氮比下牛粪高温堆肥腐熟进程研究

为有效处理奶牛场养殖粪污,建立以之为原料的牛粪有机肥高效堆肥工艺,本文通过工厂堆肥试验,以牛粪为主料,以蘑菇渣、稻壳为辅料,设置C/N=15、C/N=25、C/N=35三个处理,研究不同碳氮比原料高温堆肥过程中堆体温度、pH值、EC、C/N和养分等理化指标的变化。结果表明,C/N=25堆体达到的温度最高,达到最高温度所需时间最短且保持65℃以上时间最长。堆肥过程中各处理pH值变化基本一致,均是先升高后降低再升高最后趋于稳定,各处理EC都是先波动上升后在波动中逐渐下降并趋于稳定。各处理堆体在堆肥过程中,C/N也都呈现逐步减小的趋势,并最终保持稳定。至堆肥结束时,各处理C/N分别11.7、15.0和21.3。各处理铵态氮含量逐渐下降,硝态氮含量逐渐增加,至堆肥结束时,铵态氮的损失量分别为80.7%、36.6%和46.7%,硝态氮含量分别增加到0.61 g kg~(-1)、0.50 g kg~(-1)、0.41 g kg~(-1)。堆肥结束时,各处理胡敏酸类、富里酸类等物质成为DOM的主体部分,N1、N3处理发芽指数大于50%但小于85%,N2处理发芽指数大于85%。各处理堆肥全磷、全钾含量在堆肥结束时比堆肥初始均有所增加。因此,牛粪高温堆肥能有效处理奶牛场养殖废弃物,且C/N=25时堆肥效果最佳。

Fermentation Process under High Temperature Composting of Cow Manure with Different C/N Values

The research aimed at exploring the optimum ratio of raw material (cow manure) to auxiliary materials (mushroom residue and rice husk) at high temperature compost to effectively deal with the manure waste from cattle farm.Three treatments were set as research materials with C/N value of 15 (N1),25 (N2) and 35 (N3) to investigate the effects of C/N values on the variations of physicochemical indices including stack temperature,pH value,electronic conductivity (EC),C/N,and nutrients during the composting process.Results showed the highest temperature was reached in the shortest time and the temperature above 65 ℃C was kept for the longest time in N2 treatment.During composting process,pH value showed similar trend of ascending-descending-ascending and then tended to be stable at all the treatments.And EC value increased firstly and then decreased to stable value.The C/N value gradually decreased to stable value of 11.7,15.0 and 21.3,respectively,in the treatments of N1,N2 and N3 at the end of composting.The contents of ammonium nitrogen gradually decreased by 80.7％,36.6％ and 46.7％,respectively,while those of nitrate nitrogen increased to 0.61 g kg-1,0.50 g kg-1 and 0.41 g kg-1,respectively,in the treatments of N1,N2 and N3 at the end of composting.Dissolved organic matter was mainly from humic acids and fulvic acids at the end of composting.Germination index in N1 and N3 treatments was about 50％ ～ 85％,while it was more than 85％ in N2 treatment.Moreover,total P and total K increased in all treatments at the end compared with the beginning of composting.The high-temperature composting of cow manure and auxiliary materials could effectively transformed this kind of waste to organic fertilizer,especially when the C/N value was 25.