添加过磷酸钙对乡村有机废弃物太阳能辅助好氧堆肥氮素保持的影响

Effects of Superphosphate Addition on Nitrogen Retention in Solar-assisted Aerobic Composting of Rural Organic Wastes

太阳能辅助好氧堆肥可以实现较好的腐殖化效果,但环境温度过高易造成氮素损失。为实现太阳能辅助猪粪好氧堆肥的氮素保持效果,选择猪粪和杂草作为堆肥原料,以水稻秸秆为调理剂,设计2个堆体,即堆体1添加2.5%磷酸钙,堆体2添加5%过磷酸钙,进行为期20 d的好氧堆肥。通过分析理化性质和微生物群落变化,探究氮素保持效果。结果表明,堆体1铵态氮含量从1.40 mg·g^(-1)下降到1.34 mg·g^(-1),堆体2则从1.13 mg·g^(-1)上升到1.27 mg·g^(-1),结束堆肥时2个堆体硝态氮含量分别为0.29和0.33 mg·g^(-1),氮损失分别为22.64%和17.44%,堆体2的氮素保持效果更好,添加5%过磷酸钙有更好的保氮效果。2个堆体全磷含量分别增加26.9%和9.3%,随着过磷酸钙添加量的增加,有效磷含量有所降低,分别降低2.3%和18.3%。2个堆体种子发芽指数(GI)均大于100%,C/N值也达到腐熟要求。随着反应的进行,致病菌种〔松鼠葡萄球菌(Staphylococcus sciuri)、阴沟肠杆菌(Enterobacter cloacae)和铅黄肠球菌(Enterococcus casseliflavus)〕丰度趋于0。堆体2的pH更低,细菌群落丰度和多样性更高,氨挥发更少。堆体2中反硝化菌〔假黄色单胞菌属(Pseudoxanthomonas)、极小单胞菌属(Pusillimonas)、黄杆菌属(Flavobacterium)〕丰度低于堆体1,热酸芽孢杆菌(Bacillus thermolactis)、胺芽胞杆菌(Ammoniibacillus agariperforans)和地衣芽孢杆菌(Bacillus licheniformis)等保氮菌种丰度得到提高,有利于氮素保持。

Better humification can be achieved by solar-assisted aerobic composting.However,nitrogen loss is a simple consequence of the high composting temperature.This experiment designed two piles with pig manure and weeds as the composting raw materials and rice straw as the conditioner,and added 2.5%superphosphate to Pile 1 and 5%superphosphate to Pile 2 for 20 days in order to achieve the nitrogen retention effect of solar-assisted aerobic composting of pig manure.Physical and chemical characteristics as well as changes in the microbial population were examined to better understand the impact of nitrogen retention.The results show that the ammonium nitrogen content of Pile 1 decreased from 1.40 mg·g^(-1)to 1.34 mg·g^(-1),while the range of Pile 2 increased from 1.13 mg·g^(-1)to 1.27 mg·g^(-1).At the end of composting,the nitrate-nitrogen contents of the two piles were 0.29 and 0.33 mg·g^(-1)with the nitrogen loss ratios of 22.64%and 17.44%,respectively,indicating improved nitrogen retention in Pile 2 and better ammonia retention with the addition of 5%superphosphate.The total phosphorus of the two piles increased by 26.9%and 9.3%,and the available phosphorus content decreased by 2.3%and 18.3%,respectively with increased addition of superphosphate.The two piles′seed germination index(GI)exceeded 100%,and the C/N value also complied with the criteria for decomposition.The abundance of pathogenic species(Staphylococcus sciuri,Enterobacter cloacae,and Enterococcus casseliflavus)decreased to zero as the response developed.Pile 2 had a lower pH,a more diverse and abundant bacterial community,and less ammonia volatilization.Denitrifying bacteria(Pseudoxanthomonas,Pusillimonas,Flavobacterium)in Pile 2 was lower than that in Pile 1.At the same time,the abundances of nitrogen-preserving bacteria such as Bacillus thermolactis,Ammoniibacillus agariperforans and Bacillus licheniformis were increased,which was beneficial to nitrogen retention.