Fluorescence characteristic changes of dissolved organic matter during municipal solid waste composting

Dissolved organic matter（DOM） of municipal solid waste（MSW） consists of minerals, water, ash and humic substances, and is known to enhance plant growth. In this study, inoculating microbes（Z J, MS） were used in municipal solid wastes composting, and composting implemented a industrialized technology. During composting, dissolved organic matter was extracted from the compost and purified. The spectral characteristics of dissolved organic matter was determined by fluorescence emission, excitation, and synchronous spectroscopy. Fluorescence emission, excitation, and synchronous spectra characterized by different relative fluorescent intensities and peaks over time. Fluorescence spectra were similar to that of fulvic acid in sewage sludge, indicating the presence of dissolved organic matter with aromatic structures and a high degree of molecular polymerization. Compared with the controls with no microbial inoculation, the microbe-inoculated treatments exhibited the increase of aromatic polycondensation, in the following order： MS ＋ ZJ 〉 ZJ 〉 MS 〉 CK.

Applying organic amendment enriches nutrient status of municipal solid waste compost and its application enhances tuber yield and nutrient concentrations of potato

Elevated price of chemical fertilizers and poor nutrient content in conventional organic sources such as municipal solid waste(MSW)compost necessitate the production of nutrient enriched compost which could serve as a potential alternative organic fertilizer option.We studied three types of amended compost that were prepared by mixing 20%mustard oil cake(MOC)and 30%poultry manure(PM)or cow dung or sugarcane press mud(SPM)with 50%MSW compost.Trichoderma viride was inoculated into every type of compost.The rate of amended or unamended MSW compost application was 10 t ha^(−1).The use of different amendments improved the nutrient level of MSW compost,of which the N increment was remarkable,ranging from 1.14%N(unamended compost)to 2.9%–3.22%N depending on the types of amendment.A field experiment was conducted to evaluate performances of the amended MSW composts on the yield and nutrient content of potato(variety BARI Alu25).All compost treatments except the sole MSW compost treatment produced significantly higher tuber yields than the sole fertilizer treatment.The press mud based MSW compost+fertilizer treatment produced the highest tuber yield of 31.6 t ha^(−1)(65%increase over 100%fertilizers and 57%increase over 100%compost treatment).The tuber N concentration varied from 0.128%to 0.594%,P from 0.018%to 0.035%,K from 0.213%to 0.313%and S from 0.020%to 0.053%,with the highest result recorded with press mud+fertilizer treatment.The use of amended composts had residual effects on soil N,P,K and S contents.Thus,the treatment containing 50%fertilizer+50%compost mixture(MSW:MOC:SPM in a ratio of 5:2:3)performed the best followed by PM amended compost.It is concluded that integrated use of 10 t ha^(−1) organic amended MSW compost with chemical fertilizers can ensure higher crop yield,nutrient content and sustained soil fertility in nutrient-deficient sub-tropical soil.