不同城乡有机垃圾堆肥碳磷特征分析

Carbon and phosphorus characteristics of different urban and rural organic waste composts

【目的】为我国城乡有机垃圾的养分资源循环利用及其堆肥合理施用提供依据。【方法】选取餐厨垃圾(FW)、园林废弃物(GW)、鸡粪(ChM)和牛粪(CaM)为主要原料的4种堆肥,采用Hedley连续浸提磷分级、红外光谱分析和热重分析等方法,系统分析不同有机垃圾堆肥的碳磷特征。【结果】4种堆肥的磷素含量和组成,有机碳含量、组成和结构均存在明显差异。粪肥堆肥全磷和活性态磷的含量明显高于植物源有机垃圾堆肥(FW和GW),其中ChM堆肥水提取磷(H2O-P)含量最高,CaM堆肥NaHCO3提取磷(NaHCO3-P)含量最高。FW堆肥总有机碳高、但腐殖化系数低(胡敏酸碳/富里酸碳=0.09),水溶性有机碳、小分子有机酸和氨基酸等活性碳含量最高,芳构化程度较低、含有更多的羧酸和多糖结构,热稳定性最差。GW堆肥易氧化有机碳和腐殖酸碳含量最高,芳构化程度和热稳定性高。粪肥堆肥的腐殖酸碳含量低、水溶性碳含量较高,ChM堆肥游离氨基酸含量最高且有机酸种类丰富,CaM堆肥含有一定量的氨基酸和草酸,两种堆肥芳构化程度和热稳定性相近,且居于FW和GW之间。【结论】粪肥堆肥磷含量高、活性碳含量较高,可作为良好的磷源全部或部分替代化肥;餐厨垃圾堆肥磷素含量低,但高活性有机碳含量高,可以发挥以碳促磷作用,提高磷肥有效性;园林废弃物堆肥磷含量低,稳定态有机碳含量高,长期而言,可通过土壤改良提高土壤磷素有效性。通过不同碳磷特征堆肥间及其与化肥的合理配施,可实现碳磷协同和磷养分资源的高效循环利用。

【Objective】The present paper aimed to provide a basis for the recycling of nutrient resources of organic solid waste in urban and rural areas of China and the rational application of compost.【Method】The organic carbon(C)and phosphorus(P)characteristics of four organic waste composts,i.e.,food waste(FW),garden waste(GW),chicken manure(ChM)and cattle manure composts(CaM),were systematically analyzed by Hedley P sequential fractionation method,infrared spectroscopy and thermogravimetric analysis.【Result】The obvious differences in the content and fraction of P and the content and composition of organic C among four composts were observed.The total and labile P content of animal manure composts(ChM and CaM)were significantly higher than those of plant-derived organic waste compost(FW and GW),in which the highest content of water extracted P(H_2O-P)and NaHCO_3 extracted P(NaHCO_3-P)was observed in ChM and CaM composts,respectively.FW compost had high total organic C(TOC),but low humification index(humic C/fulvic C=0.09).Meanwhile,FW compost had the highest content of labile organic C(LOC),i.e.,dissolved organic C(DOC),light molecular organic acids(LMOA)and amino acids(AA),the lower degree of aromatization with more carboxylic acids and polysaccharide structures,and the lowest thermal stability.GW compost had the highest content of readily oxidizable organic C(ROC)and humic substances C(HSC),and a high aromatized structure and thermal stability.Animal manure compost had the lowest HSC content and the medium DOC content.ChM compost had the highest free AA content and rich LMOA species,while the CaM compost contained a certain amount of AA and oxalic acid.Two animal manure composts had a similar aromatization degree and thermal stability,which was between FW and GW.【Conclusion】Manure composts with high P content and labile organic C can be used as a good P source to completely or partially replace chemical fertilizer.FW compost has low P content but high LOC content,which can improve the availability of P fertilizer via promoting P by C.GW compost with low P content and high stable organic C,in the long run,can improve soil fertility,which in turn can enhance soil P availability.Thus,rational application of composts according to their C and P characteristics or combined application of different composts or compost with chemical fertilizers can realize the C and P synergy and the highly efficient recycling of P nutrient resources.