In Morocco, the potential of agricultural waste is estimated at 34.7 MT/year. Composting is an effective way for waste management. If badly monitored, it can affect the environment. Initial C/N ratio (C/Ni) and aeration appear to be major factors impacting the composting process. This work studied the effect of C/Ni and turning frequency (TF) on the olive pomace and turkey manure co-composting process and on the final compost quality. The study concerned the Moroccan agricultural region Chaouia-Ouardigha where these two by-products are abundant and not valued. Six heaps (H1 to H6), at three levels of C/Ni (20, 22, 28) and two levels of TF (once and twice a week), were studied. Statistical tests showed that the studied factors had no significant effects on pH, total nitrogen, electrical conductivity, and cation exchange capacity (CEC). However, C/Ni had a significant increase of 60% in nitrates. Varying from 20 to 22 or from 22 to 28, C/Ni reversed its significant effect on final C/N and CEC/organic carbon. TF reduced significantly OM and final C/N by about 22% and 9% respectively. The dendrogram showed that the six heaps could form at the end two groups: group 1 (four heaps) and group 2 (two heaps) with a similarity of about 75 and 90 respectively. C/Ni of 22 and TF of twice a week seem to be an optimum to produce a final compost of better quality. This work shows that (1) C/Ni and TF significantly impact several final quality parameters of composts from olive pomace and turkey manure, and (2) composting has a strong effect of reducing the variability between heaps initially different to produce very similar final composts.
Olive oil and turkey livestock activities in Morocco generate huge quantities of olive pomace and turkey manure, which cause soil, water, and environmental pollution. Composting is a suitable solution for these bio-wastes. This work aimed to study co-composting parameters evolution of three-phase olive pomace (OP) and turkey manure (TM) and evaluate final composts’ quality. Four heaps (OP+TM+wheat straw) were composted at different initial carbon-nitrogen (C/N) ratios (20 and 28), moistened as needed, and turned manually once or twice a week in the open air. The studied parameters have experienced ups and downs over time depending on different phases of composting and according to the initial heaps’ composition. Final composts were stable and mature with pH around neutrality, significant total nitrogen and nitrate content enhancement, and a significant reduction in organic matter for the two heaps with final values higher than 43.66%. There was a significant decrease in the C/N ratio for all heaps with final values between 11 and 13, proving the composts' stability. The increase in CEC (Cation exchange capacity) was significant with final values > 90.76 meq 100g-1, proving good humification as well as that of CEC/Organic carbon ratio (CEC/OC) with final values >1.7 proving final composts’ maturity. These results are beneficial firstly for Moroccan small-scale olive oil factories and poultry livestock farming, as it confirms the effectiveness of low-cost heap composting to manage their by-products. Secondly, farmers can use the obtained compost as an organic amendment to improve the soil's physicochemical properties and increase productivity.
Article InfoThis study aimed to investigate the co-composting time effectiveness as well as the effect of the initial Carbon/Nitrogen ratio (C/N)i variation on the hygienization of olive pomace and turkey manure. Six different heaps, at 3 levels of (C/N)i ratios: 20, 22 and 28, were installed and monitored during 6 months and assessed at three steps: At the beginning, the end of thermophilicphase and the end of curing-phase. The microbial monitoring concerned 5 microbial pathogens contents, used as hygiene microbial indicators, namely: Sulphite-Reducing Anaerobes (SRA), Escherichia Coli (E. Coli), Total Aerobic Mesophilic Flora (TAMF), Staphylococci, and Salmonella spp. Initially, the mixtures showed high TAMF and Staphylococci loads. Meanwhile, SRA and E. coli populations were relatively low and Salmonella spp. was not detected. The microbial assessment showed a significant effect of composting time on the reduction of pathogens load, except for SRA where its population has increased significantly, while the (C/N)i had a non-significant effect on pathogen content of the end-product. The final values expressed as colony-forming unit per gram (CFU g -1 ), were as follow: Sulfite-reducing Anaerobes (≤3.1 x 10 3 CFU g -1 ), E. Coli germ used as an indicator of faecal contamination (<4 x 10 1 CFU g -1 ), Total aerobic mesophilic flora (≤1.4 x 10 6 CFU g -1 ), Staphylococci (<10 CFU g -1 ) and non-detection of Salmonella spp. Finally, the seed germination tests were carried out on three different seeds: lentils (Lens culinaris), barley (Hordeum vulgare) and durum wheat (Triticum turgidum) showed that the use of the compost extract is favourable for seed germination with germination index (GI%) values exceeding 85%. These results confirm the non-phytotoxicity and maturity of the composts.
The environmental issues related to olive oil by-products and turkey manure are continuously increasing. This ecological hazard could be mitigated by the composting process. This study aimed to investigate the effect of the initial carbon to nitrogen ratio (C/N) and aeration rate (turning frequency (TF)) on mineral contents (P, K, Ca, and Na) and their leaching in the soil surface. Olive pomace (OP) and turkey manure (TM) were co-composted to prepare six mixtures at three levels of initial C/N (20, 22, and 28) and two levels of TF (once and twice a week). The results revealed a substantial effect of TF, twice a week, resulting in a loss of 36.5%, 36%, and 27% for K, Ca, and Na contents, respectively, whereas TF, once a week, preserves the maximum of nutrients in heaps with good compost maturity.The initial C/N of 28 had significantly reduced P and K by 14% and 13%, respectively, and had increased Ca and Na contents by 85% and 30 %, respectively. The leaching of almost all the studied minerals has been demonstrated after composting. Exchangeable cations have been leached more under heaps with higher C/N ratios with TF of once per week, whereas P leaching has been recorded at the maximum level under the heap with an initial C/N of 20 and turned twice weekly. The resulting composts have generally displayed good mineral quality.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.