Agyarko-Mintah Eunice, Cowie Annette, Van Zwieten Lukas, Singh Bhupinder Pal, Smillie Robert, Harden Steven, Fornasier Flavio
School of Environment and Rural Science, Agronomy and Soil Science, University of New England, Armidale, NSW 2351, Australia; Ministry of Food and Agriculture (MOFA), Accra Metropolitan Assembly, Ghana.
School of Environment and Rural Science, Agronomy and Soil Science, University of New England, Armidale, NSW 2351, Australia; NSW Department of Primary Industries, Trevenna Rd., Armidale, NSW 2351, Australia.
Waste Manag. 2017 Mar;61:129-137. doi: 10.1016/j.wasman.2016.12.009. Epub 2016 Dec 29.
The poultry industry produces abundant quantities of nutrient-rich litter, much of which is composted before use as a soil amendment. However, a large proportion of nitrogen (N) in poultry litter is lost via volatilisation during composting, with negative environmental and economic consequences. This study examined the effect of incorporating biochar during composting of poultry litter on ammonia (NH) volatilisation and N retention. Biochars produced at 550°C from greenwaste (GWB) and poultry litter (PLB) feedstocks were co-composted with a mixture of raw poultry litter and sugarcane straw [carbon (C):N ratio 10:1] in compost bins. Ammonia emissions accounted for 17% of the total N (TN) lost from the control and 12-14% from the biochar-amended compost. The TN emitted as NH, as a percentage of initial TN, was significantly lower (P<0.05) i.e. by 60% and 55% in the compost amended with GWB and PLB, respectively, relative to the control. The proportion of N retained in the finished compost, as a percentage of initial TN, was 84%, 78% and 67% for the GWB, PLB and nil biochar control, respectively. Lower concentration of dissolved organic C (DOC) together with higher activity of beta-glucosidase and leucine-aminopeptidase were found in the GWB-amended compost (cf. control). It is hypothesized that lower NH emission in the GWB-amended compost was caused not just by the higher surface area of this biochar but could also be related to greater incorporation of ammonium (NH) in organic compounds during microbial utilisation of DOC. Furthermore, the GWB-amended compost retained more NH at the end of composting than the PLB-amended compost. Results showed that addition of biochar, especially GWB, generated multiple benefits in composting of poultry litter: decrease of NH volatilisation, decrease in NH toxicity towards microorganisms, and improved N retention, thus enhancing the fertiliser value of the composted litter. It is suggested that the latter benefit is linked to a beneficial modification of the microbial environment.
家禽养殖业产生了大量营养丰富的垫料，其中大部分在用作土壤改良剂之前会进行堆肥处理。然而，家禽垫料中的很大一部分氮（N）在堆肥过程中会通过挥发而损失，这会带来负面的环境和经济影响。本研究考察了在禽畜粪便堆肥过程中添加生物炭对氨（NH₃）挥发和氮保留的影响。由绿色废弃物（GWB）和家禽粪便（PLB）原料在550°C下制备的生物炭与生家禽粪便和甘蔗秸秆的混合物（碳（C）:氮比例为10:1）在堆肥箱中共同堆肥。氨排放占对照中总氮（TN）损失的17%，而在添加生物炭的堆肥中占12 - 14%。以NH₃形式排放的TN占初始TN的百分比显著更低（P<0.05），即相对于对照，添加GWB和PLB的堆肥中分别降低了60%和55%。最终堆肥中保留的氮占初始TN的百分比，GWB、PLB和无生物炭对照分别为84%、78%和67%。在添加GWB的堆肥中（与对照相比）发现溶解有机碳（DOC）浓度较低，同时β-葡萄糖苷酶和亮氨酸氨肽酶的活性较高。据推测，添加GWB的堆肥中较低的NH₃排放不仅是由于这种生物炭的比表面积较大，还可能与微生物利用DOC过程中铵（NH₄⁺）更多地掺入有机化合物有关。此外，在堆肥结束时，添加GWB的堆肥比添加PLB的堆肥保留了更多的NH₄⁺。结果表明，添加生物炭，尤其是GWB，在禽畜粪便堆肥过程中产生了多重益处：减少NH₃挥发、降低NH₃对微生物的毒性以及提高氮保留，从而提高了堆肥垫料的肥料价值。建议后一种益处与微生物环境的有益改变有关。
