This study was conducted to produce high-quality compost using both cow manure and wood ash that can specifically be used to increase the fertility of soils in tropical regions. Increased proportions of wood ash were co-composted with cow manure. During composting, the composts produced presented the classical composting temperature curve and attain a thermophilic composting phase (about 60 oC). After 117 days of composting, the produced composts (CMA 0%; CMA 5%; CMA 10% and CMA15%) had a C/N ratio between 16 and 30, and their pH, was basic, indicating maturity. They were rich in minerals (Mg; Ca; K+; and Na+) and poor in heavy metals (Zn; Cu and Pb). Wood ash addition raise the fungal communities except for CMA 0% and did not impair significantly on bacteria communities; however, addition of high amounts of wood ash could reduce the metabolism of the microbial communities including cellulase activity that showed a proportional decrease according to the added amount except for CMA 15%. The composts showed a germination index greater than 80% at all concentrations, indicating the absence of phytotoxicity. Therefore, co-composting of cow manure with wood ash (<15%) allowed to obtain a good organic fertilizer with higher liming potential, nutrient content, and less hazardous material which could be used in farms to remediate acidity of tropical soils.

Page No.: 13-19 Volume: 15, Issue 1, 2020 ISSN: 1816-9155 Agricultural Journal Copy Right: Medwell Publications Abstract: A field study was conducted to assess the potential of cattle manure wood-ash compost in order to in order to improve soil fertility and productivity in two areas in the centre region of Cameroon distant of 200 km. The farms were amended with four type of compost, C1 (100% cattle manure compost), C2 (95% cattle manure with 10% wood ash admixture), C3 (90% cattle manure compost and 10% wood ash admixture) and C4 (85% cattle manure compost and 15% wood ash admixture). Soybean was the growing plant during the experiment which lasted three months. After the harvesting, physical, chemical, biological and plant parameters were evaluated. The compost significantly increased soil pH, electrical conductivity, total organic carbon, total nitrogen, concentrations of Ca, Mg, K, Na and total phosphorus. The composts also had a stimulatory effect on the total soil bacteria and fungi, cellulase and protease activities. Improvement soil physical, chemical and microbial parameters enhanced biomass production and yield. In summary, cattle manure wood-ashcomposts could be used for alleviating soil acidity and improve soil fertility of tropical acid soils. Future, research is needed to address its sustainability in a long-term study.

A greenhouse study was conducted to assess the potential of green waste wood ash compost on a tropical acid soil. Four types of compost (prepared with 0, 5, 10 and 15% of wood ash prior composting) were used to amend an Oxisol from the centre region of Cameroon. The different composts were mixed with the soil in 1/4 proportions (w/w); the experimental design was a completely randomized block with three replicates per treatment. The different treatments were planted with soybean (Glycine max L.) for three month growing period. Compost amendment increased the soil pH, organic carbon, total nitrogen and total phosphorus. Bacterial and fungal biomass together with cellulase and protease activities also increased in amended soil. Following soil chemical, physical and chemical parameters, plant growth and yield also improved in compost treated sols. However, compost prepared with 15% wood ash additive showed trends of inhibition of the soil microbiota. It can be concluded that green waste wood ash compost could be used as a suitable soil fertilizer for tropical acid soils, although precautions are to be taken when using these composts prepared with addition of wood ash ≥ 15%.

A comparative study was conducted to (1) assess the potential of raw sewage used for urban agriculture to disseminate bacterial resistance in two cities of different size in Cameroon (Central Africa) and (2) compare the outcome with data obtained in Burkina Faso (West Africa). In each city, raw sewage samples were sampled from open-air canals in three neighbourhoods. After DNA extraction, the microbial population structure and function, presence of pathogens, antibiotic resistance genes and Enterobacteriaceae plasmids replicons were analysed using whole genome shotgun sequencing and bioinformatics. Forty-three pathogen-specific virulenc e factor genes were detected in the sewage. Eighteen different incompatibility groups of Enterobacteriaceae plasmid replicon types (ColE, A/C, B/O/K/Z, FIA, FIB, FIC, FII, H, I, N, P, Q, R, T, U, W, X, and Y) implicated in the spread of drug-resistance genes were present in the sewage samples. One hundred thirty-six antibiotic resistance genes commonly associated with MDR plasmid carriage were identified in both cities. Enterobacteriaceae plasmid replicons and ARGs found in Burkina Faso wastewaters were also present in Cameroon waters. The abundance of Enterobacteriaceae, plasmid replicons and antibiotic resistance genes was greater in Yaounde, the city with the greater population. In conclusion, the clinically relevant environmental resistome found in raw sewage used for urban agriculture is common in West and Central Africa. The size of the city impacts on the abundance of drug-resistant genes in the raw sewage while ESBL gene abundance is related to the prevalence of Enterobacteriaceae along with plasmid Enterobacteriaceae abundance associated to faecal pollution.

A metagenomic study was conducted to investigate the impact of raw wastewater use for irrigation in urban agriculture on the development of bacterial resistance in soil. Soil samples were collected in two African countries, from three different cities (each with irrigated and non-irrigated plots). Basic physical and chemical analysis were conducted, and the presence of selected antibiotic residues was assessed. Microbial DNA was extracted, quantified and sequenced. Microbial population structure and function, presence of horizontally transferable antibiotic resistance genes and Enterobacteriaceae plasmids replicons were analysed using bioinformatics. The relative prevalence of Proteobacteria and Bacteroidetes and sequence reads coding for microbial adaptation and growth were higher in irrigated fields; 33 and 26 transferable ARGs were found in irrigated and non-irrigated fields sequence reads, respectively. Extended spectrum β-lactam genes identified in irrigated fields included bla CARB-3, bla OXA-347, bla OXA-5 and bla Rm3. Concentration of sulfamethoxazole, ciprofloxacin and enrofloxacin in soils influenced the selection of antibiotic resistance genes encoding resistance against amphenicol, β-lactams, and tetracyclines. Ten Enterobacteriaceae plasmid amplicon groups were identified in the fields, five were common to both, two (IncW and IncP1) and three (IncY, IncFIB and IncFIA) were found in irrigated and non-irrigated fields, respectively. In conclusion, wastewater irrigation affected both soil microbial diversity and functions. Irrigated fields have more diverse transferable antibiotic resistance genes, including ESBL genes that encode resistance to β-lactams antibiotics, except cephamycins and carbapenems. Even more, critical concentrations of antibiotic residues select for multiple and cross resistance. The findings from African cities show that wastewater irrigation in urban agriculture presents a serious public health risk for farmworkers and consumers by spread of bacterial resistance.

A study was conducted to investigate the impact of raw wastewater use for irrigation on dissemination of bacterial resistance in urban agriculture in African cities. The pollution of agricultural fields by selected antibiotic residues was assessed. The structure and functions of the soil microbial communities, presence of antibiotic resistance genes of human clinical importance and Enterobacteriaceae plasmid replicons were analysed using high throughput metagenomic sequencing. In irrigated fields, the richness of Bacteroidetes and Firmicutes phyla increased by 65% and 15.7%, respectively; functions allocated to microbial communities' adaptation and development increased by 3%. Abundance of antibiotic resistance genes of medical interest was 27% greater in irrigated fields. Extended spectrum β-lactamase genes identified in irrigated fields included blaCARB-3, blaOXA-347, blaOXA-5 and blaRm3. The presence of ARGs encoding resistance to amphenicols, β-lactams, and tetracyclines were associated with the higher concentrations of ciprofloxacin, enrofloxacin and sulfamethoxazole in irrigated fields. Ten Enterobacteriaceae plasmid amplicon groups involved in the wide distribution of ARGs were identified in the fields. IncQ2, ColE, IncFIC, IncQ1, and IncFII were found in both farming systems; IncW and IncP1 in irrigated fields; and IncY, IncFIB and IncFIA in non-irrigated fields. In conclusion, raw wastewater irrigated soils in African cities could represent a vector for the spread of antibiotic resistance, thus threatening human and animal health. Consumers of products from these farms and farmers could be at risk of acquiring infections due to drug-resistant bacteria.

High-throughput sequencing data of soil microbial communities in non-irrigated and irrigated soils with raw sewage in African cities are presented in this report. These data were collected to study the potential of wastewater use in urban agriculture to disseminate bacterial resistance in soil. Soil samples were collected in three cities in two African countries. Each city had two sectors (irrigated and non-irrigated). After collection, biomass samples were purified, DNA from soil was extracted, quantified and sequenced using multiplex Illumina high-throughput sequencing. The sequence count of the six metagenome datasets ranges from 3,258,523,350 bp to 4,120,454,250 bp; the mean sequence length post quality control average was 149 +/- 3 bp. The mechanisms of resistance encoded by the identified antibiotic resistance genes (ARGs) in the metagenomic data were dominated by antibiotic inactivation enzymes (64.7% and 71.9%), followed by antibiotic target replacement (14.7% and 12.5%), antibiotic target protection (11.8% and 9.4%) and efflux pumps (6.3% and 8.8%) in bacterial DNA isolated from irrigated and non-irrigated fields, respectively. The datasets will be useful for the scientific community working in the area of bacterial resistance dissemination from the environment. They can be used for further understanding of bacterial drug-resistance gene prevalence and acquisition in wastewater irrigated soils. The data reported herein was used for the article, titled "Raw wastewater irrigation for urban agriculture in three African cities increases the abundance of transferable antibiotic resistance genes in soil, including those encoding Extended spectrum beta-lactamase (ESBLs)" Bougnom et al. (2020) [1]. (C) 2019 The Authors. Published by Elsevier Inc.

State of art metagenomics were used to investigate the microbial population, antibiotic resistance genes and plasmids of medical interest in wastewater used for urban agriculture in Ouagadougou (Burkina Faso). Wastewater samples were collected from three canals near agricultural fields in three neighbourhoods. Assessment of microbial population diversity revealed different microbial patterns among the different samples. Sequencing reads from the wastewaters revealed different functional specializations of microbial communities, with the predominance of carbohydrates and proteins metabolism functions. Eleven pathogen-specific and 56 orthologous virulence factor genes were detected in the wastewater samples. These virulence factors are usually found in human pathogens that cause gastroenteritis and/or diarrhoea. A wide range of antibiotic resistance genes was identified; 81 are transmissible by mobile genetic elements. These included seven different extended spectrum β-lactamase genes encoding synthesis of four enzyme families, including two metallo-β-lactamases (blaAIM-1 and blaGES-21). Ten different incompatibility groups of Enterobacteriaceae plasmid replicons (ColE, FIB, FIC, FII, P, Q, R, U, Y, and A/C), and 30 plasmid replicon types from Gram-positive bacteria. All are implicated in the wide distribution of antibiotic resistance genes. We conclude that wastewater used for urban agriculture in the city represents a high risk for spreading bacteria and antimicrobial resistance among humans and animals.

ADVERTISEMENT RETURN TO ISSUEPREVViewpointNEXTWastewater for Urban Agriculture: A Significant Factor in Dissemination of Antibiotic ResistanceBlaise P. Bougnom†‡ and Laura J.V. Piddock*†View Author Information† Institute for Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.‡ Department of Microbiology, University of Yaounde 1, P.O. Box 812, Yaounde, Cameroon*E-mail: [email protected]Cite this: Environ. Sci. Technol. 2017, 51, 11, 5863–5864Publication Date (Web):May 10, 2017Publication History Received10 April 2017Published online10 May 2017Published inissue 6 June 2017https://pubs.acs.org/doi/10.1021/acs.est.7b01852https://doi.org/10.1021/acs.est.7b01852newsACS PublicationsCopyright © 2017 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views4406Altmetric-Citations48LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (663 KB) Get e-AlertscloseSUBJECTS:Agriculture,Antimicrobial agents,Bacteria,Food,Wastewater Get e-Alerts

Groundnut (Arachis hypogea L.) production is a key farming activity in Cameroon, since it substantially contributes to human nutrition, economic wealth of farmers and soil fertility. Most cropping systems in sub Saharan Africa are limited by low soil fertility and subjected to the slash-and-burn agriculture. A study was conducted to investigate the potential of cattle manure ash, derived from cooking activities as soil conditioner in order to improve soil fertility and groundnut performances in two sites in the Adamawa region (Cameroon). The results showed that cattle manure ash slightly increased soil pH, soil moisture, SOM, Corg and C/N ratio in amended plots. Cattle manure ash improved nodule weight and increased arbuscular mycorrhizal fungi colonization in one site, that was translated to better N assimilation, and dry weight of both groundnut varieties used in the study. Future studies are needed to evaluate the full potential of cattle manure ash application, alone and/or associated with others organic wastes for sustainable agriculture in the tropics.

Biodynamic (organic) and integrated apple orchards can differ in their soil chemical and microbiological properties which may have implications for disease control and long-term soil fertility. Soil samples were collected from three different apple orchards (each with biodynamic and integrated plots) during three different seasons. Physical and chemical characteristics of the soils under the two management systems did not show clear differences. Basal respiration and microbial biomass were higher in organic farms, while the metabolic quotient in organic farms was lower (or equal in one case) to that of integrated farms. There were also seasonal variations. Principal component analysis of the DGGE banding patterns of dominant fungal communities revealed no influence of the farming practices. Analysis of the bacterial communities with the COMPOCHIP microarray showed that certain probes targeting bacteria known to be degraders of biocides were predominantly found in integrated farming plots, while no difference between the two management practices concerning the presence of plant growth promoting rhizobacteria was evident. In conclusion, despite the reduced use of chemicals in integrated farming (compared to conventional), soil microbial properties (CO2 production and biomass) were different to those found in biodynamic farming, while the microbial spectrum did not significantly change.

A field study was conducted to investigate the potential of residues from renewable energy production for fertilizing pastures. Six treatments including manure or biogas sludge, each combined with wood ash at 0, 1 and 3 t ha(-1) were applied at the same N equivalent (190 kg N ha(-1)). Three soil samplings and two cuttings were carried out within one growing season (4 months). Plots amended with biogas sludge had a higher EC and total N, those amended with wood ash at 3 t ha(-1) scored higher soil pH, EC and C/N ratio. K concentrations increased in plots amended with biogas sludge. Basal respiration, microbial biomass, metabolic quotient and C-mic/C-org from the differently treated soils were not influenced neither by the nature of the organic waste nor the amount of wood ash added. The time of sampling (seasonal effects) was found to influence the soil pH, EC and all the microbial parameters. A higher forage yield and lower proportion of leguminous plants was observed for soil treated with anaerobic sludge.It may be concluded that the combination of anaerobic sludge and wood ash has a double positive effect, both on some selected soil chemical parameters as well as on total forage yield. The results obtained need to be confirmed in long term experiments, and the best practice for a combined application still needs to be worked out. (C) 2012 Elsevier Ltd. All rights reserved.

Infertility of acid soils is a major limitation to crop production on highly weathered and leached soils throughout the world. The main characteristics of these soils are their low pH, low levels of organic matter, Ca, Mg, P, or Mo deficiency, Al or Mn toxicity, or both, and very low mineralization and nitrification rates. Lime is generally recommended to correct soil acidity, but lime is unaffordable for resource-poor farmers in the tropics. Many alternatives have been proposed, and among them products from organic waste materials, e.g., composts, have proven to be an efficient alternative to the use of lime. Wood ash is a potential source of trace elements, nutrients, and lime. Wood ash could be used as an additive to fertilizer, and wood ash admixture to organic wastes prior to composting is known to improve compost quality and may reduce the amount of compost required to raise the pH to suitable levels. Wood ash compost as a liming agent as a replacement for lime could potentially aid in remediating acidity and base deficiency as well as boosting the soil microbial pool in tropical agricultural soils.

In a greenhouse study we investigated the potential of wood ash amended composts to ameliorate acid tropical soils. Three composts (produced with 0%, 8% and 16% wood ash admixture, respectively), and two acid tropical soils, an Oxisol and an Ultisol from Cameroon were used for that purpose. In this paper we report the effects on the soil microbiota at the end of the cropping cycle (100 days soybean plus 100 days fallow). Principal coordinate analysis of denaturing gradient gel electrophoresis patterns of ammonium oxidizing bacteria (AOB) indicated that they were stimulated by addition of compost. AOB communities of the compost treated soils differed from the control ones, and no significant differences among the different composts were found in both soils. Soil type clearly influenced the AOB community. Ester-linked phospholipid fatty acids increased in compost treated soils, up to an ash amendment of 8%. The ratio of cyclopropyl-to-monoenoic precursor (cy19:0 to 18:1 omega 7), which has been proposed as an indicator of stress conditions, decreased upon compost addition and did not differ among the treated soils. Community level physiological profiling indicated an increase in activities after addition of compost, the effect was most distinct for the compost with 16% ash.Based on these results, compost with moderate close of wood ash is considered beneficial to the soil microbiota and could thus be used for ameliorating tropical acid soils. (C) 2010 Elsevier B.V. All rights reserved.

Within the framework aiming at assessing the potential risk of the use of wood ash amended composts to tropical acid soils, a greenhouse experiment was conducted with two acid soils (Oxisol and Ultisol) collected from Cameroon and amended with three types of compost 3:1 (w/w) prepared with 0, 8 and 16% wood ash prior to composting, respectively. They were planted with soybean (Glycine max L) for 100 d. Addition of organic waste composts increased soil pH, SCM, WHC, EC, total C and N. Concentrations of exchangeable Al and NH(4)(+)-N decreased while those of NO(3)(-)-N and phosphorous increased. The exchangeable cation (Ca, Mg, Na and K) and micronutrient (Zn and Cu) concentrations increased while concentrations of Fe and Mn decreased. The C/N ratio of treated soils ranged from 12 to 14. Soil pH, concentrations of Fe and Mn were higher; EC and nitrate concentration were lower under ash compost amendment. Eight percent ash amendment to compost yielded best results in many aspects. Concentration of exchangeable Al was most decreased in soils treated with compost without ash. Plant biomass production was not significantly enhanced by compost amendment.This lack of an effect may be attributed to a soil pH (> 7.7) beyond the optimum for soybean (6.2). Summarising the results, composts with ash addition could serve the purpose of ameliorating acid tropical soils, albeit the optimal amendment rates still need to be addressed in future research. (C) 2009 Elsevier B.V. All rights reserved.