Effect of a lime-based bedding conditioner on physical-chemical characteristics and microbiological counts of recycled manure solids.

Bedding materials are aimed at providing a safe and comfortable resting environment for cows. Control of pathogen proliferation in these substrates is crucial to prevent intramammary infections in dairy cows, as these can significantly impact milk quality, cow health, and farm productivity. This is particularly relevant in the case of organic bedding substrates, including manure-derived materials. This study aimed to evaluate the in vitro effect of a lime-based conditioner (LBC), composed of CaCO3MgCO3 and Ca(OH) 2 * Mg(OH)2, at increasing concentrations on the physical-chemical characteristics and bacterial counts of untreated anaerobically digested manure solids (ADMS) and separated raw manure solids (SRMS). Unused ADMS and SRMS were evaluated at four LBC weight-based concentrations: 0 (as untreated control), 10, 15, and 20% of LBC inclusion. The bedding materials were assessed immediately after LBC addition (0 h) and after 24, 72, and 168 h of storage at 28°C. The dry matter content (DM), and pH were measured for all the time points. Standard microbiological methods were used to assess total bacterial counts (TBC), other Gram-negative bacteria, coliforms, Escherichia coli, and streptococci and streptococci-like organism (SSLO). It was observed a linear increase in both DM and pH with increasing concentrations of LBC. Specifically, for each percentage unit increase of LBC, the DM of ADMS and SRMS increased by 0.73 and 0.71%, respectively. Similarly, for each percentage unit of LBC, the pH of ADMS and SRMS increased by 0.15 and 0.19, respectively. Conversely, a linear decrease in TBC, Gram-negative bacteria, coliforms, E. coli, and SSLO was observed with increasing concentrations of the LBC. Manure-derived materials without the inclusion of the LBC had bacterial counts that tended to remain high or increase over time. Otherwise, bedding materials with LBC application had reduced bacterial counts. Based on the results of the present study, it was observed that the higher the concentration of LBC, the more significant the reduction of bacterial counts. Specifically, bacterial recovery was lower when higher concentrations of LBC were applied. Our findings underscore the potential of LBC in effectively controlling environmental bacteria and improving the physical-chemical characteristics of manure-derived bedding materials to improve cow health and welfare.

Effect of Cow Dung Additions on Tropical and Mediterranean Earth Mortars-Mechanical Performance and Water Resistance.

Cow dung (CD) is a material that has been used for millennia by humanity as a stabilizer in earth building techniques in vernacular architecture. However, this stabilization has been little addressed scientifically. In this study, the effect of CD additions was assessed on earth mortars produced with one type of earth from Brazil and two other types from Portugal (from Monsaraz and Caparica). The effect of two volumetric proportions of CD additions were assessed: 10% and 20% of earth + sand. The German standard DIN 18947 was used to perform the physical and mechanical tests, and classify the mortars. In comparison to the reference mortars without CD, the additions reduced linear shrinkage and cracking. An increase in flexural and compressive strengths was not observed only in mortars produced with earth from Monsaraz. In mortars produced with the earth from Caparica, the addition of 10% of CD increased flexural strength by 15% and compressive strength by 34%. For mortars produced with the earth from Brazil, the addition of 10% of CD increased these mechanical strengths by 40%. The increase in adhesive strength and water resistance promoted by the CD additions was observed in mortars produced with all three types of earth. Applied on ceramic brick, the proportion of 10% of CD increased the adherence by 100% for the three types of earth. Applied on adobe, the same proportion of CD also increased it more than 50%. For the water immersion test, the CD additions made possible for the mortar specimens not to disintegrate after a 30 min immersion, with the 20% proportion being more efficient. The effects of the CD on mechanical performance, including adhesion, were more significant on the tropical earth mortars but the effects on water resistance were more significant on the Mediterranean earthen mortars. CD has shown its positive effects and potential for both tropical and Mediterranean earthen plasters and renders tested, justifying being further studied as an eco-efficient bio-stabilizer.

Low-performance diagnosis of covered anaerobic lagoons as a waste management strategy in the intensive dairy industry.

Covered anaerobic lagoons (CALs) are Latin America's main livestock waste treatment systems. Mexico has 680 CALs that present low biogas yields (0.05 m3 m-3 digester d-1) and low COD removal rates (< 60%). This work focused on diagnosing CAL´s low performance in dairy farms by determining and analyzing operational parameters. Seven CALs located in the main dairy basin of Mexico were analyzed. The sampling areas for each CAL were the supernatant, the active zone, settled sludge, and digester inlet and outlet. The variation of the process parameter values corroborated that CALs appeared stratified and not working as expected. The sludge zone, comprising 50-58% of total solids content and 1-15% of total CALs volume, showed an elemental compounds content suitable for organic fertilizer (340, 48, and 5 kg t-1 of C, N, and S, respectively). However, this zone contained, at least, 85% of the slowly hydrolysable material; the methanogenic potential was less than 87 mL CH4 g VS-1, and the C/N ratio ranged from 4.9 to 17, outside of the optimal range. The biogas produced did not exceed 60% of methane content and more than 3000 ppm of H2S. The sludge zone significantly influences the lagoon's dynamics since it is a nutrient sink. Furthermore, the lack of agitation is the leading cause for the low energy yield and the low removal of organic matter rate. This work provides valuable information to address the operational problems within the CALs improving our understanding that shall allow proposing reactivation alternatives.

Multidrug-resistant Escherichia coli strains isolated from swine manure biofertilizer in Brazil.

Escherichia coli is one of the key bacteria responsible for a variety of diseases in humans and livestock-associated infections around the globe. It is the leading cause of mortality in neonatal and weaned piglets in pig husbandry, causing diarrhea and significant harm to the industry. Furthermore, the frequent and intensive use of antimicrobials for the prevention of diseases, particularly gastrointestinal diseases, may promote the selection of multidrug-resistant (MDR) strains. These resistant genotypes can be transmitted through the excrement of animals, including swine. It is common practice to use porcine manure processed by biodigesters as fertilizer. This study aimed to examine the antimicrobial susceptibility, the presence of virulence genes frequently associated with pathotypes of intestinal pathogenic E. coli (InPEC), and antimicrobial resistance genes (ARGs) of 28 E. coli isolates collected from swine manure fertilizers. In addition, the enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) technique was used to investigate the genetic relationship among the strains. Using disk diffusion, the antimicrobial susceptibility profiles of the strains were determined. Using polymerase chain reaction (PCR), 14 distinct virulence genes associated with the most prevalent diarrhea and intestinal pathogenic E. coli (DEC/InPEC) and five ARGs were analyzed. All isolates tested positive for multidrug resistance. There was no detection of any of the 14 virulence genes associated with InPECs, indicating the presence of an avirulent commensal microbiota. Molecular classification by ERIC-PCR revealed that the majority of isolates (27 isolates) coalesced into a larger cluster with a genetic similarity of 47.7%; only one strain did not cluster in this cluster, indicating a high level of genetic diversity among the analyzed isolates. Thus, it is of the utmost importance to conduct epidemiological surveillance of animal breeding facilities in order to determine their microbiota and formulate plans to reduce the use of antimicrobials and improve animal welfare.

How the type of dairy production system affects the nutrient balance from an environmental and economic perspective.

The knowledge of nutrient flow in dairy farms has to be explored to find optimized strategies for efficient nutrient conversion to milk. This study aims to improve the understanding of variances in nitrogen and phosphorus balance and efficiency indicators between dairy farm systems. The study analyzed 67 dairy cattle farms located in the watershed Lajeado Tacongava, Rio Grande do Sul State, Brazil. Selected dairy farms represented three production systems: confined (3 farms); semi-confined (7 farms); pasture-based (57 farms). Input-output nutrient balances were calculated at the dairy system level for nitrogen and phosphorus over a year. Inputs are feed and fertilizer and outputs are milk and meat. The main nitrogen and phosphorus input on the all farms resulted from the feed. The average N and P surplus on pasture-based farms were 352 and 49 kg ha-1 year-1, respectively. In semi-confined systems were 508 and 63 kg ha-1 year-1 and in confined systems were 786 and 70 kg ha-1 year-1. When considering the monetary value of the total N surplus, the averages were US$ 2.615, 4.950, and 12.171 for pasture-based, semi-confined and confined systems respectively. Monetary values of P surplus were US$ 346, 588, and 1119 for pasture-based, semi-confined and confined. The productive aspects that most determined the values of N and P surplus were the total number of lactating cows and the farm area. Results indicate that surplus can partially replace chemical nitrogen fertilizer, except in the confined system, and fully replace phosphorus fertilizer. Confined farms presented values to use surplus as fertilizer greater than the crop demand. For the other production systems, it happens only for phosphorus. Large variability between dairy farms of the same production system and between different production systems was observed. It reflects the inherent productive, economic, and environmental conditions of each farm and system.

Evaluating antibiotic occurrence, degradation, and environmental risks in poultry litter within Argentina's agricultural hub.

This study explores the relationship between poultry farming's antibiotic administration practices and residual antibiotic levels in the litter before its application onto agricultural soils. Twenty-three antibiotics were performed across 19 Argentinean farms representing diverse antibiotic management practices. Analysis revealed up to 20 antibiotics from eight chemical classes in poultry litter samples, with tylosin, enrofloxacin, and salinomycin being the most relevant drugs. Farms with restricted antibiotic use in feed exhibited lower residual concentrations. A self-heating treatment was tested to reduce litter antibiotic levels. Although a 60 % reduction of antibiotics was found after treatment, prevalent compounds persisted at residual levels. Regulatory measures and comprehensive litter treatments pre-application are crucial to mitigate environmental risks. This is the first study that provides insight on the occurrence of >20 drugs in real poultry production scenarios from Latin America and demonstrates how relatively simple treatments can be readily applied to decrease the associated environmental risks.

Understanding nitrogen dynamics in the Brazilian beef industry: A comprehensive decadal analysis.

Brazil stands as a prominent beef producer and exporter, witnessing major transformations and expansions in its production chain over the past 20 years. These changes have prompted concerns regarding waste generation and environmental pressure. This study employs material flow analysis (MFA) to quantify nitrogen flows throughout the cattle slaughter process and subsequent beef consumption in Brazil, spanning from 2011 to 2021. The analysis encompasses co-production streams like leather, tallow, viscera, and blood. Nitrogen use efficiency (NUE) and the nitrogen cascade indicator (NCI) were used to evaluate efficiency and nitrogen accumulation in the production chain. Nitrogen inputs in the system increased by 8.47 %, while beef production rose by 7.29 %. In contrast, per capita beef consumption decreased by 1.29 kg, despite an overall consumption increase of 2.84 %, attributed to population growth in Brazil. Beef exports witnessed a notable surge of 86.03 %. Conversely, human excreta and food waste losses experienced increments of 10.88 % and 2.84 %, respectively. Examining NUE reveals the highest values during the slaughter phase (90 %), followed by processing, transportation, and storage stages (79-88 %). The consumption phase exhibited the lowest NUE values (29-34 %). Regarding the cumulative nitrogen effect, the NCI varied between 77 % and 82 % throughout the study period. This highlights opportunities for enhancing nitrogen use efficiency, particularly by addressing food waste at the consumer level. Notably, the study observes nitrogen accumulation across the Brazilian beef production chain, potentially contributing to the nitrogen cascade effect and heightening environmental pressure. Recognizing these dynamics provides avenues for targeted improvements, emphasizing the need to address nitrogen-related challenges and enhance sustainability in the beef production and consumption landscape.

Livestock waste management for energy recovery in Brazil: a life cycle assessment approach.

Livestock farming has exerted intense environmental pressure on our planet. The high emissions to the environment and the high demands of resources for the production process have encouraged the search for decarbonization and circularity in the livestock sector. In this context, the objective of this study was to evaluate and compare the environmental performance of two different uses for biogas generated in the anaerobic digestion of animal waste, either for electricity generation or biomethane. For this purpose, a life cycle assessment approach was applied to evaluate the potential of anaerobic digestion as a management technology for three different livestock wastes, related to beef cattle, dairy, and sheep in the Brazilian animal production context. The results suggest that the treatment scenarios focusing on biomethane generation were able to mitigate the highest percentage of damages (77 to 108%) in the global warming category when compared to the scenarios without the use of anaerobic digestion (3.00·102 to 3.71·103 kgCO2 eq) or in the perspective of electricity generation (mitigation of 74 to 96%). In terms of freshwater eutrophication, the generation of electricity (- 2.17·10-2 to 2.31·10-3 kg P eq) is more favorable than the purification of biogas to biomethane (- 1.73·10-2 to 2.44·10-3 kg P eq), due to the loss of methane in the upgrading process. In terms of terrestrial ecotoxicity, all scenarios are very similar, with negative values (- 1.19·101 to - 7.17·102 kg 1,4-DCB) due to the benefit of nutrient recovery, especially nitrogen, associated with the use of digestate as fertilizer, which was one of the critical points in all scenarios. Based on these results, it is evident that proper management of all stages of the treatment life cycle is the key to decarbonization and circularity in livestock waste management. The biogas use does not present different effects on the environmental performance of the scenarios studied, demonstrating that the purpose should be chosen according to the needs of each plant or management system.

Unveiling antimicrobial resistance in Chilean fertilized soils: a One Health perspective on environmental AMR surveillance.

Antimicrobial resistance (AMR) poses a significant threat to humans and animals as well as the environment. Within agricultural settings, the utilization of antimicrobial agents in animal husbandry can lead to the emergence of antimicrobial resistance. In Chile, the widespread use of animal-derived organic amendments, including manure and compost, requires an examination of the potential emergence of AMR resulting from their application. The aim of this research was to identify and compare AMR genes found in fertilized soils and manure in Los Andes city, Chile. Soil samples were collected from an agricultural field, comprising unamended soils, amended soils, and manure used for crop fertilization. The selected genes (n = 28) included genes associated with resistance to beta-lactams, tetracyclines, sulfonamides, polymyxins, macrolides, quinolones, aminoglycosides, as well as mobile genetic elements and multidrug resistance genes. Twenty genes were successfully identified in the samples. Tetracycline resistance genes displayed the highest prevalence, followed by MGE and sulfonamides, while quinolone resistance genes were comparatively less abundant. Notably, blaOXA, sulA, tetO, tetW, tetM, aac (6) ib., and intI1, exhibited higher frequencies in unamended soils, indicating their potential persistence within the soil microbiome and contribution to the perpetuation of AMR over time. Given the complex nature of AMR, it is crucial to adopt an integrated surveillance framework that embraces the One Health approach, involving multiple sectors, to effectively address this challenge. This study represents the first investigation of antimicrobial resistance genes in agricultural soils in Chile, shedding light on the presence and dynamics of AMR in this context.

Natural Ecuadorian zeolite: An effective ammonia adsorbent to enhance methane production from swine waste.

Anaerobic digestion (AD) of swine waste allows obtaining renewable energy, biofertilizer and the reduction of environmental impacts. However, the low C:N ratio of pig manure generates high concentrations of ammonia nitrogen in the digestion process, reducing methane production. Zeolite is an effective ammonia adsorbent; thus, in this research the ammonia adsorption capacity of natural Ecuadorian zeolite was studied under different operating conditions. Subsequently, its effect on methane production from swine waste was evaluated using three doses of zeolite, 1.0, 4.0 and 8.0 g, in 1 L batch bioreactors. The results showed that the Ecuadorian natural zeolite has an adsorption capacity of around 19 mgNH3-N gZ-1 when using ammonium chloride solution and, an adsorption capacity between 37 and 65 mgNH3-N gZ-1 using swine waste. On the other hand, the addition of zeolite had a significant effect on methane production (p < 0.01). The zeolite doses that provided the highest methane production were 4.0 and 8.0 g L-1, which led to values of 0.375 and 0.365 Nm3CH4 kgVS-1, compared to the values of 0.350 and 0.343 Nm3CH4 kgVS-1 that were obtained for the treatments without addition of zeolite and using a dose of 1.0 g L-1, respectively. Addition of natural Ecuadorian zeolite meant not only a significant increase on methane production in the AD of swine waste, but also a better quality of the biogas with higher percentages of methane and lower concentrations of H2S.

Response of 'criolla' potato (Solanum tuberosum) cultivar Colombia to mineral organic fertilization

The 'Criolla' potato (Solanum tuberosum) phureja group cultivated in the inter-Andean valleys of the high tropics, is commonly fertilized only with mineral nutrients in conventional production, without the use of soil test and use of organic fertilizers. The purpose of this study was to determine the potential of organic chicken manure as a source of nutrients to increase yield and quality in 'Criolla' potatoes compared to conventional fertilization. Treatments evaluated were organic chicken manure, mineral nutrition based on soil tests, organic manure mixed with mineral nutrition, and conventional nutrition based on farmers' typical nutrition plans. In plant response conventional and mineral treatments mixed with organic matter were the best in leaf area and dry weight of shoot and tuber. Treatment with mineral nutrition mixed with organic manure (2 and 6 t) obtained the largest length of the main stems. The best yield response was obtained with conventional nutrition, while the major size was obtained with mineral and mineral combined with organic treatments. According to the results, the best response was obtained with the application of mineral nutrition in the combination of 6 t ha-1 organic manure.

La papa criolla (Solanum tuberosum) grupo phureja es cultivada en los valles interandinos del trópico alto, comúnmente fertilizada con nutrientes minerales en la producción convencional, sin hacer uso de análisis de suelos y nutrición con fertilizantes orgánicos. El objetivo de este estudio fue determinar el potencial de la materia orgánica de gallinaza, como fuente de nutrientes, para incrementar el rendimiento y la calidad en la papa criolla, comparándola con la nutrición convencional. Los tratamientos evaluados fueron gallinaza, nutrición mineral, basado en análisis de suelos; nutrición mineral, combinada con materia orgánica y un tratamiento soportado en la fertilización convencional, con base en los planes nutricionales, típicos de los agricultores. En las respuestas de la planta, los tratamientos convencionales y minerales mezclados con nutrición mineral obtuvieron los valores más altos en área foliar y peso seco de la parte aérea y el tubérculo. En longitud de tallo, la mejor respuesta se obtuvo con los tratamientos minerales mezclados con materia orgánica (2 y 6 toneladas). La mejor respuesta en rendimiento fue obtenida en la nutrición mineral convencional, mientras que las papas con mayor calibre, se lograron con los tratamientos mineral y mineral mezclado con orgánico. De acuerdo con los resultados, la mejor respuesta en cultivo se puede obtener con la nutrición mineral, en combinación con 6 toneladas de materia orgánica.

Mucuna pruriens cannot develop phytoremediation of tebuthiuron in agricultural soil with vinasse: a morphometrical and ecotoxicological analysis.

Pesticides offer stakeholders cost-effective solutions to control weeds. Nevertheless, such active compounds can manifest as severe environmental pollutants when escaping from agroecosystems into surrounding natural ecosystems, driving the need to remediate them. We, hence, analyzed whether Mucuna pruriens can develop a potential phytoremediator for treating tebuthiuron (TBT) in soil with vinasse. We exposed M. pruriens to microenvironments containing tebuthiuron at 0.5, 1, 1.5, and 2 (standard dose) L ha-1 and vinasse at 75, 150 (industrial recommendation), and 300 m3·ha-1. Experimental units without organic compounds represented controls. We assessed M. pruriens for morphometrical features, such as plant height and stem diameter and shoot/root dry mass, over approximately 60 days. We obtained evidence for M. pruriens not effectively removing tebuthiuron from the terrestrial medium. Such a pesticide developed phytotoxicity, significantly limiting its germination and growth. The higher the dose, the more negatively the tebuthiuron impacted the plant. In addition, introducing vinasse into the system, irrespective of volume, intensified the damage to photosynthetic and non-photosynthetic structures. Equally important, its antagonist action further decreased the production and accumulation of biomass. As M. pruriens could not effectively extract tebuthiuron from the soil, it could allow neither Crotalaria juncea nor Lactuca sativa to grow on synthetic media containing residual pesticide. An atypical performance of such testing (tebuthiuron-sensitive) organisms over independent ecotoxicological bioassays validated inefficient phytoremediation. Hence, M. pruriens could not offer a functional remediative option to treat environmental pollution by tebuthiuron in agroecosystems where vinasse occurs, such as sugarcane-producing areas. Although M. pruriens considered a tebuthiuron phytoremediator as cited in the literature, satisfactory results did not occur in our research due to high concentrations of vinasse in the soil. Therefore, this information requires more specific studies about the influence of high concentrations of organic matter on M. pruriens productivity and phytoremediation performance.

Evaluation of the methanogenic potential of anaerobic digestion of agro-industrial wastes.

Waste management technologies have become a way to generate value-added products. Anaerobic digestion (AD) allows biogas generation by treating organic wastes. In this work, the methanogenic potentials of anaerobic digestion of rumen and chicken manure, two typical agro-industrial wastes from the Colombian Caribbean region, were evaluated. On a first stage, the effect of temperature on anaerobic digestion of manure inoculated with liquid rumen was measured. Results revealed that the thermophilic digestion produces more biogas (up to 47% higher than the mesophilic digestion), but the mesophilic digestion has better biogas quality (up to 20% more methane than the thermophilic digestion). On the second experimental stage, it was assessed the effect of temperature regimen and the addition of fat-oil-grease (FOG) on cumulative biogas production, methane percentage, and physicochemical parameters. It was found that the anaerobic digestion of the rumen with FOG in mesophilic conditions had the best performance in terms of quantity and quality of biogas (2520 NL CH4/kg VS, CH4 93%, H2S 1 mg/L, H2O 16 mg/L). Finally, rumen and manure had methane concentrations above 40% in all cases studied, after 60 days of anaerobic digestion. It was concluded that rumen and manure are good candidates for biogas generation.

Influence of anaerobic biotransformation process of agro-industrial waste with Lactobacillus acidophilus on the rheological parameters: case of study of pig manure.

This study evaluated the rheological behavior of the pig waste biotransformation process to produce lactic acid (LA) and biomass with Lactobacillus acidophilus in a stirred reactor. In addition, cell growth, carbohydrate consumption, and LA production were measured at three different agitation speeds, 100, 150, and 200 rpm at 37 °C, with a reaction time of 52 h. During the development of the process, the kinetic and rheological parameters were obtained using the logistic, Gompertz, generalized Gompertz, Ostwald de Waele, and Herschel-Bulkley mathematical models, respectively. The substrate used was pig manure, to which molasses was added at 12% v/v to increase the concentration of carbohydrates. The results suggest that mass exchange is favorable at low agitation speeds. Nevertheless, the presence of molasses rich in carbohydrates as a carbon source modifies the characteristics of the fluid, dilatant (n > 1) at the beginning of the process to end up as pseudoplastic (n < 1) due to the addition of exopolysaccharides and the modification of the physical structure of the substrate. This effect was confirmed by the Herschel-Bulkley model, which presented a better fit to the data obtained, in addition to finding a direct relationship between viscosity and pH that can be used as variables for the control of bioconversion processes of pig manure into biomass rich in Lactobacillus acidophilus.

Potential of vermicomposting with mixtures of animal manure and vegetable leaves in the development of Eisenia foetida, microbial biomass, and enzymatic activity under semi-arid conditions.

Vermicomposting is the bio-oxidation and stabilization of organic matter involving relationships between the action of earthworms and microorganisms and the activation and dynamics of several enzyme activities. Semi-arid farmers to make (extra) money and organic production, produce their vermicompost using plant residues and animal manure, but there is no information about the final product generated. Thus, this study aimed to analyze the potential of vermicomposting with mixtures of animal manure and vegetable leaves in the development of Eisenia foetida, microbial biomass, and enzymatic activity in the semi-arid region, Brazil. The experimental design applied was randomized block in a 6 × 4 factorial scheme with four replicates, with six treatments (mixtures of cattle manure, goat manure, cashew leaves, and catanduva leaves) and evaluated at four-time intervals (30, 60, 90, and 120 days of vermicomposting). The treatments were placed in polyethylene pots in the same site, environmental conditions, and residues proportions as used by farmers. The characteristics analyzed were the number of earthworms (NE), total earthworm biomass (TEB) and earthworm multiplication index (MI), microbial biomass carbon (MBC), and activities of enzymes ß-glucosidase, dehydrogenase, alkaline and acid phosphatases. The cattle manure vermicomposted shows the highest average values observed for NE, MI, TEB, MBC, and enzymatic activity, regardless of the plant leaves mix. In general, the enzymes activities were found in the descending order of ß-glucosidase > alkaline phosphatase > dehydrogenase > acid phosphatase. The maturation dynamics of vermicompost were characterized by a decline in the microbial population and number and biomass of earthworms in the substrate and consequently a decrease in new enzyme synthesis and degradation of the remaining enzyme pool. Microbial biomass and enzymatic activity were indicators for changes in the quality of vermicompost.

The Use of Raw Poultry Waste as Soil Amendment Under Field Conditions Caused a Loss of Bacterial Genetic Diversity Together with an Increment of Eutrophic Risk and Phytotoxic Effects.

Poultry waste has been used as fertilizer to avoid soil degradation caused by the long-term application of chemical fertilizer. However, few studies have evaluated field conditions where livestock wastes have been used for extended periods of time. In this study, physicochemical parameters, metabarcoding of the 16S rRNA gene, and ecotoxicity indexes were used for the characterization of chicken manure and poultry litter to examine the effect of their application to agricultural soils for 10 years. Poultry wastes showed high concentrations of nutrients and increased electrical conductivity leading to phytotoxic effects on seeds. The bacterial communities were dominated by typical members of the gastrointestinal tract, noting the presence of pathogenic bacteria. Soils subjected to poultry manure applications showed statistically higher values of total and extractable phosphorous, increasing the risk of eutrophication. Moreover, while the soil bacterial community remained dominated by the ones related to the biogeochemical cycles of nutrients and plant growth promotion, losses of alpha diversity were observed on treated soils. Altogether, our work would contribute to understand the effects of common local agricultural practices and support the adoption of the waste treatment process in compliance with environmental sustainability guidelines.

Effect of the initial pH on the anaerobic digestion process of dairy cattle manure.

Anaerobic digestion (AD) has recently been studied to obtain products of greater interest than biogas, such as volatile fatty acids (VFAs) and phytoregulators. The effect of the initial pH of cow manure and the fermentation time of the AD on the microbial composition, VFAs, indole-3-acetic acid (IAA) and gibberellic acid (GA3) production was evaluated. The cow manure (7% solids) was adjusted to initial pH values of 5.5, 6.5, 7.5, and 8.5, and the AD products were analyzed every four days until day 20. The initial pH and the fermentation time had an important effect on the production of metabolites. During AD, only the hydrolytic and acidogenic stages were identified, and the bacteria found were from the phyla Firmicutes, Bacteroidetes, Actinobacteria, and Spirochaetes. The most abundant genera produced in the four AD were Caproiciproducens, Clostridium sensu stricto 1, Romboutsia, Paeniclostridium, Turicibacter, Peptostreptococcaceae, Ruminococcaceae and Fonticella. The highest amount of VFAs was obtained at pH 8.5, and the production of the acids was butyric > acetic > propionic. The maximum production of GA3 and IAA was at an initial pH of 6.5 on day 20 and a pH of 5.5 on day 4, respectively. There was a strong correlation (> 0.8) between the most abundant microorganisms and the production of VFAs and GA3. The anaerobic digestion of cow manure is a good alternative for the production of VFAs, GA3 and IAA.

Assessment of livestock greenhouse gases in Colombia between 1995 and 2015.

The livestock sector in Colombia significantly participates in national economic dynamics but makes significant worldwide contributions to greenhouse gas emissions. Hence, climate change mitigation in this sector is essential. This study aims to assess the greenhouse gas in the livestock sector. The results are reported in methane emissions (CH4) and nitrous oxide (N2O) from enteric fermentation, and N2O by manure management based on the information from the Emission Database for Global Atmospheric Research (EDGAR), in all cases expressed as dioxide of carbon (CO2eq). The emissions obtained from the EDGAR database for 2015 were proportional to the values of the National Inventory of Greenhouse Gases published by the Institute of Hydrology, Meteorology, and Environmental Studies (IDEAM) in 2016. Colombia is the 12th on global, 4th in America and 2nd in South America position by livestock GHG emission, and is the dominant source in all economic sector. The results showed higher records for CH4 emissions during the years 2010 and 2015, while the N2O emissions were higher during 2015. The regions with the highest emissions of CH4 and N2O corresponded to the northwestern area of Colombia. The Spearman correlation test showed a positive correlation between the CH4 emissions, and the age groups studied. The post hoc analysis of the Kruskal-Wallis test showed a more significant influence on CH4 emissions.

Biodigestion System Made of Polyethylene and Polystyrene Insulator for Dog Farm (on the Example of the Republic of Chile).

Anaerobic digestion is a system that can have a high environmental impact through the use of different wastes to obtain biogas and its consequent use for the generation of renewable energy. The objective of this study was to implement a polyethylene biodigester, using polystyrene for thermal insulation in a dog kennel, using canine feces collected in the same place during a period of 5 months to obtain biogas and energy. The results indicated that biogas production started on day 30 and stopped during the winter period with low temperatures; therefore, from day 54 onwards, equine manure was added to continue producing biogas. Although biogas was obtained, the biodigester did not function optimally, due to the fact that the materials used in its construction did not provide efficient insulation from the low external temperatures; the low C/N ratio of the canine feces, which led to a reduction in the processing of the methanogenic bacteria; and the low amount of feces collected for use. In general, the use of a biodigester can provide a tool for the biological processing and management of organic waste, yielding a cumulative source of renewable energy and ensuring environmental safety.

Host Status of Cover Crops for the Management of Pratylenchus Jaehni on Coffee.

The lesion nematode Pratylenchus jaehni occurs at low frequency in Brazilian coffee orchards but could provoke extensive root damage. Intercropping cover crops is a traditional practice in Brazilian coffee orchards, and the use of non-hosts of P. jaehni as cover crops may be a useful management method. In this work, 10 cover crops were tested concerning reproduction of P. jaehni. Cajanus cajan, Canavalia ensiformis, and Mucuna deeringiana are cover crops commonly used as intercropping in coffee orchards, but they must not be used in orchards infested with P. jaehni, because they are good hosts of this nematode. Brachiaria ruziziensis, Crotalaria juncea, Dolichos lablab, and Pennisetum glaucum were considered poor hosts. Helianthus annuus cv. Catissol and cv. Uruguai and Crotalaria spectabilis proved to be non-hosts to P. jaehni, and therefore, they are the cover crops recommended in coffee orchards infested with this nematode.