Effect of different initial C/N ratio of cow manure and straw on microbial quality of compost

Abstract

Purpose The effect of different initial carbon to nitrogen (C/N) ratios on the prevalence of Salmonella spp., fecal coliforms and helminth eggs over composts produced from several mixtures of maize straw (S) and dairy manure (M) was investigated. Methods Four C/N ratios (21, 22, 27, and 38) were evaluated, including one with manure only (C/N 21). The composting process was performed under field conditions in northern Mexico. Results The process lasted 51 days; Salmonella spp. was reduced 1-2 log (> 94%) in most treatments, except for the C/N ratio of 27 which achieved < 1 log reduction (about 35%). Fecal coliforms elimination was 3-4 log (> 99%) in all treatments while helminth eggs achieved < 1 log (72-87%, depending on treatment). In this study, the mixture with initial C/N ratio of 22 (25% S + 75% M), which had the lowest amount of straw, resulted in the highest elimination of Salmonella spp., fecal coliforms, and helminth eggs. This mix complied with current Mexican sanitary regulations for compost use. The composts produced from the other C/N ratios complied only with the limits for one or two of the microorganisms that were analyzed. Conclusions The initial C/N ratios in compost from straw and manure influences microbial reduction. The final C/N of the mixes ranged from 14 to 16, indicative of stable compost. Compared to fecal coliforms, Salmonella spp. and helminth eggs were more resilient.

Evaluation of compost quality from municipal solid waste integrated with organic additive in Mizan–Aman town, Southwest Ethiopia

“…The lower compost temperature was recorded in T5 (26.4 ± 1.0 °C). Similarly, a research reported that temperature fluctuation in the compost pile overtime related to consumption of organics by microorganisms [ 30 ]. In general, in all treatments an increase in temperature was observed at the early weeks (2–4 weeks) and a temperature decline at later weeks (5–10 weeks) of the composting period.…”

Static composting of cow manure and corn stalk covered with a membrane in cold regions

“…The C/N and the water content of the composting mixture were about 30:1 and 60%, according to the research studies and our laboratory compost results ( Sánchez et al, 2017 ; Macias-Corral et al, 2019 ). Here, 1.592 tons of cow dung, 2.556 tons of grounded straw, and 1.852 tons of water were mixed.…”

“…In composting environments, it will take a long time to obtain the same results. It took about 4 days to inactivate Salmonella when the composting temperature was higher than 55°C [Marilyn et al, 2009; Macias-corral et al, 2019 ]. E. coli could be eliminated in 25 days when the composting temperature was between 45 and 55°C ( Wichuk and McCartney, 2007 ; Macias-corral et al, 2019 ).…”

“…It took about 4 days to inactivate Salmonella when the composting temperature was higher than 55°C [Marilyn et al, 2009; Macias-corral et al, 2019 ]. E. coli could be eliminated in 25 days when the composting temperature was between 45 and 55°C ( Wichuk and McCartney, 2007 ; Macias-corral et al, 2019 ). As a result, certain requirements for composting temperature and duration were proposed in order to meet the hygienic standards.…”

Utilization of Blood Meal, Slaughterhouse Waste and Bio Gas Slurry into Fertilizer

“…In addition, in the fourth week, through physical observation, ground lice and worms were found. [23] stated the application of organic fertilizer containing blood meal facilitates the development of earthworms. At the end of the composting period, the mixture of ingredients has dark colored and smelly soil.…”