鸟粪石结晶反应在猪粪和玉米秸秆堆肥中的应用

Application of Struvite Crystallization on Co-composting of Swine Manure and Cornstalk

控制堆肥化过程中的氨气排放是减少堆肥氮素损失的关键,应用鸟粪石结晶原理,以氢氧化镁[Mg(OH)2]和磷酸(H3PO4)作为固定剂,按照摩尔比为1∶1,摩尔数为初始氮的15.4%添加到猪粪和玉米秸秆的堆肥物料中,通过26d的密闭式底部强制通风静态堆肥.结果发现,添加固定剂的堆肥处理B中铵态氮含量显著提高,堆肥结束时,NH4+-N含量为10.7g·kg-1,是未添加固定剂的处理A的3倍,全氮含量为36.9g·kg-1,比处理A提高10g·kg-1.同时,固定剂的添加促进了有机质的分解,堆肥结束时处理B的有机碳降解率比处理A高2%,发芽率指数表明,处理B的腐熟度(96%)高于处理A(82%).扫描电镜(scanning electron microscopy,SEM)及X射线能谱(energy dispersive X-ray spectroscopy,EDS)分析证实了堆肥产品中有MgNH4PO4.6H2O的存在.说明通过添加Mg(OH)2和H3PO4,可以改变堆肥的理化性质,促进堆肥的降解和腐熟,并通过鸟粪石结晶反应将堆肥中的铵态氮固定下来,有效提高了堆肥的营养价值.

Aimed at controlling the nitrogen loss caused by the ammonia gas emission during composting, the mixtures of magnesium hydroxide [Mg（OH）2 ] and phosphoric acid （H3 PO4 ） were added into composting materials of swine manure and cornstalk. After 26 d composting, ammonical nitrogen and total nitrogen were improved obviously, which were 10.7 g·kg^-1 and 36.9 g·kg^-1 respectively in amended treatment （B） ,while they were 7.7 g·kg^-1 and 26.8 g·kg^-1 in un-amended trial. By analysis of the total organic carbon,it suggested that amendments accelerated the degradation of organic matter, germination index test showed the maturity of trial B（96% ） was better than trial A（82% ） in final compost. The scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS） analysis confirmed the existence of struvite （MgNH4PO4·6H2O）. These results indicated that Mg （OH）2 and H3PO4 could accelerate the degradation of organic matter, and reduce the ammonia emission by struvite crystallization reaction.