Manure Storage Research Articles

Needs for increasing the storage infrastructure for manure in Poland in the light of the requirements of the new action programme to implement the Nitrates Directive

The aim of the research was to determine the need to increase the infrastructure for storing livestock manure in Poland in groups of farms divided on the basis of the number of animal herds. Using individual data from Statistics Poland and using the balance method, the maladjustment of the infrastructure to the new legal requirements regarding the storage of manure was estimated. It was determined that meeting the standards included in the new action program in force in the country under the Nitrates Directive will require the construction or expansion of manure plates with an area of 2,539.6 thousand m2, new tanks with a capacity of 3,437.2 thousand m3 and covering the existing ones with a capacity of 3,170.6 thousand m3. Total investment costs were estimated at PLN 5,907,913.40 thousand, i.e. approximately EUR 1.4 billion. The requirements in force for most entities since January 1, 2025, will bring far-reaching changes, leading to the concentration of animals in very large herds and deepening the regionalisation of production. Both positive and negative effects of this process on the natural environment were indicated.

РЕЗУЛЬТАТЫ ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ НАСОСА-ПОНТОНА ДЛЯ ЛАГУН-НАВОЗОХРАНИЛИЩ

The main methods of preparing organic fertilizers from manure runoff coming from pigbreeding complexes are analyzed. In particular, one of the effective technologies is the technology of homogenization of runoff in lagoons-manure storages. The purpose of the article is to substantiate the design and parameters of the pontoon pump for homogenization and pumping of liquid organic fertilizers (LOF) from lagoons-manure storages. The analysis of studies on the problem of homogenization and pumping of LFO from lagoons-manure storages made it possible to formulate scientific prerequisites for improving the working process of mixing manure runoff in manure storages and pumping them to the place of application to the soil. Their essence lies in the substantiation of the design parameters of the transporting screw - length, diameter and frequency of its rotation. A new design of the pontoon pump is described and a diagram of its location when changing the depth of the lagoon-manure storage is presented. A diagram of the working process for the pontoon pump, consisting of three stages, is developed. The pump flow rate, the total specific energy of the pumped liquid at the pump outlet, and the pressure created by the conveying screw are determined. The analysis of the forces applied to a point in the conveying part of the pontoon pump is performed, which made it possible to determine the trigonometric functions of the angular parameter. Research is conducted using the multifactorial experiment technique. An analytical dependence of the change in the pump pressure on the diameter of the conveying screw casing and the length of the conveying screw at a constant screw rotation frequency is obtained. A graphical dependence of the response surface is constructed. The obtained design parameters ensure the efficient flow of the working process of pumping ZOU from the manure storage lagoon with the specified parameters of pressure and flow rate.

К ВОПРОСУ ПЕРЕКАЧКИ И ВНЕСЕНИЯ В ПОЧВУ ЖИДКИХ ОРГАНИЧЕСКИХ УДОБРЕНИЙ ИЗ ЛАГУН-НАВОЗОХРАНИЛИЩ

The most effective technology for processing, storing and using manure effluents from livestock complexes into organic fertilizers, which involves homogenizing the manure mass in a manure storage lagoon using a pontoon pump, has been substantiated. Shortcomings have been identified in ensuring the working process of pumping from manure storage lagoons and applying liquid organic fertilizers (ZHOU) to the soil, in connection with which a promising unit for transporting ZHOU from a manure storage lagoon and applying them to the soil has been justified and developed. The purpose of the article is to increase the efficiency of the process of pumping and applying ZHOU from manure storage lagoons using an improved unit. An improved design of the unit for applying ZHOU has been developed, which has a high uniformity of distribution of the working fluid over the width of the unit. The test conditions of the unit for applying ZHOU in the fields adjacent to the livestock complex are given. A method has been developed for determining the uniformity of the distribution of ZHOU along the discharge hoses of the unit. Experimental studies of the prototype unit have been carried out. Based on the results of measurements, a histogram of comparative tests with a known variant and graphical dependences of the uniformity of the distribution of ZHOU over the discharge hoses are constructed. The efficiency of the unit is determined, which consists in the uniform distribution of the working fluid of the ZHOU over the width of the unit, due to the use of a distribution dome.

A modular framework to assess biological resource utilization impacts (BIORIM)

The strong influence of biological processes and site conditions, the large diversity in management, compositional changes of agricultural produce, and the circularity of processes challenge the assessment of environmental impacts of the bioeconomy. This paper introduces a novel sustainability assessment and material flow model to study biological resource utilization impacts (BIORIM) which aims to address these challenges. The model represents important bioeconomic production systems (e.g. arable land, dairy farm, biogas plant) and considers input properties, production parameters such as site conditions or management, and different emission factors when calculating products and emissions. For this reason, the functions that represent the conversion processes need to be executed in the correct order when analysing larger production networks. The model keeps full track of mass, carbon and nitrogen flows, and therefore allows assessing how much is lost during processing, ending up in the produce and is recycled. The modelling approach is illustrated at the example of a dairy farm where dairy manure is used as an organic fertilizer for fodder crop production in the following year. This is compared to a scenario that includes a biogas plant. The comparison of manure storage to biogas production reveals that this change does not only affects direct emissions. Biogas production leads to higher carbon losses and thus negatively affects the humus balance. The manure storage, on the other hand, leads to higher nitrogen losses, which result in a lower fertilization value of the manure, and therefore a higher amount of mineral fertilizer is required in the following year. Together with the emission savings from the energy production, this results in a lower global warming effect of the biogas scenario. The study shows that it is important to consider the interplay of processes when assessing impacts of bioeconomic production systems.

Effect of long-term storage of cattle manure on its energy potential and biodegradability

Abstract In recent years in Russia, due to the complicated geopolitical situation in some border areas, biogas plants have been considered not only as waste utilization facilities, but also as reserve energy sources, which are safer than traditional - nuclear power plants. In this context, the development of an algorithm for the flexible operation of a biogas plant is particularly relevant, which gives rise to the need to study the stability of the system under the influence of different unfavourable factors. In this work, the influence of long-term storage of cattle manure on its energy potential and biodegradability is studied. The specific methane yield in the test variant with manure stored for 10 months before anaerobic fermentation was 1.41±0.55 ml/g oDM, which is 6.23 times lower than in the test variant with fresh manure; the methane content of manure after long-term storage is 9.66 times lower and the degree of decomposition of its organic matter is 2.72 times lower compared to similar indicators of manure processed without preliminary storage. However, the specific biogas yield from long-term stored manure is 1.66 times higher than the control, which indicates intensive formation of other gases. Thus, long-term storage has a negative impact on the energy potential of cattle manure; if it is necessary to process it in a biogas plant, it is advisable to combine it with more energy-intensive raw materials.

Estimation of Ammonia Emission Inventory Using Life Cycle Assessment Based on Livestock Manure Flow: A Case Study of the Manure Management Sector in Korea

Ammonia is one of the precursor gases in the formation of particulate matter (PM) that reacts with nitrogen oxides and sulfur oxides in the atmosphere. Based on the Clean Air Policy Support System (CAPSS) of Korea, the annual ammonia emissions amounted to 261,207 tons in 2020 and the agricultural source (manure management sector) contributes the highest proportion of the ammonia inventory. However, the methodology for the study of ammonia emissions in Korea has some limitations regarding the representativeness of the sites selected and the reliability of the measurement method. In this study, we aimed to recalculate the ammonia emissions from the livestock industry in Korea using the UK’s estimation method, which uses the life cycle assessment of livestock manure. Three major animal types, i.e., cattle (beef cattle and dairy cows), pigs and chickens, and three major processes based on the manure flow, i.e., housing, manure storage and treatment and land application processes, were considered. The total ammonia emissions were estimated to be approximately 33% higher than the official ammonia emissions stated by the CAPSS. For the manure flow, the ammonia emissions were the highest from land application processes. The ammonia emissions from dairy cow and poultry manure were much higher than those stated by the CAPSS, while the emissions from beef cattle and pig manure showed similar levels. The methodology used in this study can offer an alternative approach to the ammonia emission estimation of the manure management sector in the agriculture industry of Korea. Korean emission factors based on the manure flow should be developed and applied in the future.

Pig manure degradation and carbon emission: Measuring and modeling combined aerobic-anaerobic transformations.

Greenhouse gas emissions from liquid livestock manure storage significantly contribute to global warming. Accurate farm-scale models are essential for predicting these emissions and evaluating manure management strategies, but they rely on multiple parameters describing carbon loss dynamics. Surface respiration may significantly influence carbon loss and methane emission, yet it is not explicitly included in current models. We conducted experiments to measure pig manure surface respiration rate and its effect on organic matter degradation and methane and carbon dioxide emissions. Manure was incubated for 283 days at 10°C or 20°C under aerobic or anaerobic conditions, while measuring methane and carbon dioxide emission. This was followed by anaerobic digestion at 38°C. Surface respiration reduced the organic matter content, and the effect was temperature dependent. Methane emission was not affected by surface respiration, suggesting that substrate availability was not rate-limiting for methanogenesis. Surface respiration rates were 18.1±3.5g CO2 m-2 day-1 at 10°C and 37.1±13.1g CO2 m-2 day-1 at 20°C (mean±standard deviation) and were consistent with microsensor measurements of oxygen consumption in different manure surfaces. Based on these results, temperature- and surface area-dependent respiration was incorporated in the existing anaerobic biodegradation model (ABM). Simulations showed that surface respiration accounts for 29% of carbon losses in a typical pig house and 8% for outdoor storage. Developing and refining algorithms for diverse carbon transformations, such as surface respiration, is crucial for evaluating the potential for methane emission and identification of variables that control emissions at the farm scale.

An Effective Biochar Application for Reducing Nitrogen Emissions from Buffalo Digestate Storage Tank

Open manure storage contributes to the release of ammonia (NH3) into the atmosphere. Tank floating covers represent an effective technique to reduce NH3 emissions and biochar has been gain attention as a floating cover and as manure additive. Nevertheless, the mechanisms involved in the process still need to be elucidated since they are influenced by the biochar specific properties, application methods and dose. This work aims to study: (i) the biochar adsorption performances in an NH3 aqueous solution under conditions relevant to manure storage and (ii) the effect of different biochar application methods and dosage on NH3 emissions from buffalo digestate storage. The results show that a 43% reduction in NH3 emissions can be achieved by using biochar as a floating cover of 2 cm rather than as an additive. Moreover, the results show that the biochar produced at 550 °C acts as an adsorbent material for both NH4+ and NH3, by being adsorbed on the biochar surface in the form of NH4+ after H+ abstraction from the acid groups. A minimum cover height of 2 cm is required to give compactness and provide an additional resistance to the gas transfer, which is even more relevant than the adsorption in reducing NH3 emissions.

Biochar as an Alternative Litter Additive to Mitigate Gaseous Emissions from Broiler Housing and Subsequent Storage

Broiler farming is a significant source of gaseous emissions. The aim of this study was to assess the effects of different litter additives on the emission of NH3, N2O, CO2, and CH4 during broiler housing and subsequent manure storage. The gaseous emissions from the housing facilities were evaluated during one fattening cycle in environmentally controlled rooms with three different additives applied to the litter material (10% w/w aluminum sulphate or biochar and 2.50 mg m−2 urease inhibitor), as well as a control. A storage experiment was conducted under laboratory conditions for 90 days to evaluate the influence of these three additives on gaseous losses. During broiler housing, the results indicated that NH3 emissions were reduced significantly (40–60%) by litter additives, while global warming potential (GWP) emissions were reduced significantly (31%) by Alum. The addition of Biochar (a 58% reduction) had the same significant effect as Alum (a 60% reduction) to mitigate these losses. The re-application of Urease (a 41% reduction) may be required to reach an equal or higher reduction. During storage, NH3 and GWP emissions were not significantly affected by the litter additives. During broiler housing and subsequent manure storage, NH3 emissions were reduced significantly (22–41%) by litter additives, whereas GWP emissions did not decrease significantly. Globally, it can be concluded that Biochar appears to be a good alternative to Alum due to its equal effectiveness in mitigating NH3 losses, without increasing the GWP potential in the housing and avoiding pollution swapping.

An integral assessment of the impact of diet and manure management on whole-farm greenhouse gas and nitrogen emissions in dairy cattle production systems using process-based models

Feed management decisions are crucial in mitigating greenhouse gas (GHG) and nitrogen (N) emissions from ruminant farming systems. However, assessing the downstream impact of diet on emissions in dairy production systems is complex, due to the multifunctional relationships between a variety of distinct but interconnected sources such as animals, housing, manure storage, and soil. Therefore, there is a need for an integral assessment of the direct and indirect GHG and N emissions that considers the underlying processes of carbon (C), N and their drivers within the system. Here we show the relevance of using a cascade of process-based (PB) models, such as Dutch Tier 3 and (Manure)-DNDC (Denitrification-Decomposition) models, for capturing the downstream influence of diet on whole-farm emissions in two contrasting case study dairy farms: a confinement system in Germany and a pasture-based system in New Zealand. Considerable variation was found in emissions on a per hectare and per head basis, and across different farm components and categories of animals. Moreover, the confinement system had a farm C emission of 1.01 kg CO2-eq kg−1 fat and protein corrected milk (FPCM), and a farm N emission of 0.0300 kg N kg−1 FPCM. In contrast, the pasture-based system had a lower farm C and N emission averaging 0.82 kg CO2-eq kg−1 FPCM and 0.006 kg N kg−1 FPCM, respectively over the 4-year period. The results demonstrate how inputs and outputs could be made compatible and exchangeable across the PB models for quantifying dietary effects on whole-farm GHG and N emissions.

Effectiveness of the Sustainable Manure Pile Model for Ammonia Emission and Soil

In order to reduce odor emissions and surface water pollution while storing manure in field heaps near a barn, there is a challenge in properly designing manure-storage areas. Therefore, it is important to assess what solutions and conditions, considering environmental requirements, should be considered when storing manure in field heaps. The goal of the research is to determine the impact of various factors on the risk of nutrient leaching, soil, and gas emissions from solid manure heaps, considering climatic factors in the environment. Through various scientific studies, a manure pile model has been developed and evaluated for its impact on the risk of potential leaching and odor emissions (using hyperspectral gas emission analysis mass flow method) from manure and the dynamics of the 0–80 cm soil layer properties (nitrate (N-NO3) and nitrite (N-NO2), ammonia (NH3), mineral, and total N). Based on the research results, requirements for manure management and storage during the prohibited fertilization period were established, considering the requirements for nitrates from agricultural sources in Lithuania. An optimal new manure heap model has been identified—a layer of not less than 20 cm of compacted straw (density 150–200 kg m−3) or a 10 cm layer of peat for absorbing manure slurries is formed on the soil surface, the manure heap is surrounded by an earth embankment not less than 30 cm high, the manure heap is covered with a layer of finely chopped straw not less than 10 cm thick, or 5 cm of sawdust, or 5 cm of peat. The manure is stored in the heap for 6–12 months. Following the research results, requirements for manure management and storage during the prohibited fertilization period were established, considering the requirements for nitrates from agricultural sources in Lithuania, applicable to the northern part of the temperate climate zone and applying similar requirements to the relevant countries.

Greenhouse gas emissions and nutrient use efficiency assessment of 6 New York organic dairies

Improving nutrient use efficiency and reducing GHG emissions are important environmental priorities for organic-certified dairy operations. The objectives of this research were to quantify annual nutrient use and GHG emissions in 6 organic New York dairy farms. Farm-gate nutrient mass balances (NMB) were estimated with the Cornell NMB calculator. Whole-farm GHG emissions were estimated using the Cool Farm Tool (CFT) and COMET. Farm-gate NMB were low, ranging from -6.5 to 19 kg N/ha for N1 (without legume N fixation), 26 to 71 kg N/ha for N2 (including N fixation), -2.4 to 8.2 kg P/ha for P, and 1.1 to 19.8 kg K/ha for K. Additional nutrient imports, coupled with nutrient management planning, adequate legume stands, and diet balancing may help improve P balances and ensure no N deficiencies in the system. Estimates of annual GHG emissions intensity ranged from 0.98 to 2.10 kg of CO2-equivalents (CO2-eq) per kilogram of fat- and protein-corrected milk (FPCM) estimated by CFT, and from 0.69 to 2.48 kg CO2-eq/kg FPCM estimated by COMET. Enteric fermentation, feed production, and fuel and energy use represented the largest sources of GHG. For farms with liquid manure storages, manure management was also a significant source. Estimates of soil carbon (C) stock changes from CFT were in agreement with or smaller than previous studies, and estimates from COMET were in agreement or greater. Variability and uncertainty in the results for soil C stock change indicate that more research and new protocols are needed. The effects of individual management changes on GHG emissions intensity were small, ranging from -8 to +7% in CFT, and -8% to +8% in COMET. The management changes that resulted in the largest reductions in GHG emissions intensity included increasing individual cow productivity and ratio of milk to total feed, and implementation of manure treatment systems.

New York state, regional and county level nitrogen and phosphorus balances for harvested cropland

New York (NY) state is one of five states that collectively produce >50% of the annual milk supply within the United States. The local environment allows farmers to integrate crop and livestock systems, facilitating cycling of manure nutrients back to cropland. Thus, dairy provides NY with benefits, opportunities, and challenges in terms of environmental sustainability, climate resiliency, and a circular agricultural economy. Improved balancing of crop nitrogen (N) and phosphorus (P) needs and supply with manure and fertilizer, is key for a circular agricultural economy. The objectives of this study were to calculate and evaluate (1) regional and county level N and P balances of harvested cropland; and (2) contribution of manure to a circular agricultural economy for NY. Nutrient balances were calculated for 2017 (most recent Census year) as the difference in the amount of nutrient input through purchased fertilizer and recoverable manure, and the amount removed in harvested crops. Atmospheric N deposition and legume N fixation, and manure nutrient losses during collection, transfer, storage, and treatment were estimated too. The 2017 P balance was 10 kg P ha−1 (9 lb. P ac−1). The N balance was between 39 kg N ha−1 (35 lb. N ac−1) and 95 kg N ha−1 (85 lb. N ac−1), depending on the proportion of legume cropland assumed to receive manure. Redistribution and application of manure to meet P-removal on non-legume cropland only leaves a surplus of 3 kg P ha−1 (3 lb. P ac−1). Applying surplus manure to legume and non-legume cropland results in a slight, state-level, P deficit. In both scenarios, the large N deficit that cannot be met through legume N fixation alone indicates purchased fertilizer is required. These results show NY’s ability to capitalize on the value of manure without excessive risk to the environment. Greater circularity of agricultural production in NY will need to consider benefits and trade-offs of applying manure to legume cropland. As milk production increases in the state, implementation of advanced manure treatment, storage, and manure application and livestock feeding practices will be needed to increase the circularity and sustainability of the agricultural sector in NY.

Organic or Non-organic Agriculture: Comparison of Organic and Conventional Farming Sustainability

Reduction of the level of greenhouse gas emissions from sector of agriculture are one of the serious issues across European Union. The dairy industry is responsible for generating a significant amount of emissions from enteric fermentation, manure and long-term storage. The amount of emissions produced depends highly on factors such as livestock feeding and manure management systems, feed intensity and quality. Farms that have high milk yield also produce more liquid manure, leading to an increase in overall emissions from manure management.Organic farming has been valued as one of the most suitable solutions to conventional agriculture for the achievement of climate goals. Organic farming can be described as a farming approach based on prevention, ecological processes, and the restriction of pesticides. Restricting pests and lower yields can have a negative impact on production costs and revenues. However, organic farming has lower operating costs and higher product costs, which can increase overall incomes.The research aims to evaluate the environmental, economic and social dimensions of conventional and organic farming, comparing were comparing on their integral environmental, economic and social sustainability. The core element for the sustainability assessment is the construction of the composite sustainability index using data for scientific literature, reports and statistics.

Manure temperature prediction for slurry storage in Sweden: Model validation including effects of shading, snow cover and mixing

Measuring and modelling manure temperatures are crucial for estimating greenhouse gas emissions from liquid manure storage. The manure temperature was recorded at various depths in two swine slurry storage tanks situated in Vallentuna (VA) and Örsundsbro (OR) in Sweden. These data were used to assess the effectiveness of a revised mechanistic model for estimating manure temperatures, which incorporates the effects of wall shading, snow cover, and manure input mixing. The average manure temperatures were higher than air temperatures in the summer and fall. This indicated that using air temperature would result in an underestimation of methane emissions when applying the 2019 IPCC Refinement methodology. The revised model estimated manure temperatures for spring, summer, fall, and winter as 4.8, 16.1, 7.8, and 2.6 °C at the VA tank and 11.6, 17.1, 9.5, and 3.6 °C at the OR tank. The root mean square errors between daily simulated and observed temperatures in the summer decreased in both tanks due to incorporating shadow effect into the revised model. Fall estimates did not improve, possibly because of uncertainties from slurry removal and higher precipitation inputs. Sensitivity analysis indicated that solar radiative heat input was reduced with higher tank walls and smaller tank diameters when applying the revised model. Wall shading may influence manure temperatures in tanks with small diameters at high-latitude locations. This study offers insights into understanding the relationship between manure temperatures and its thermal balance influenced by latitude, storage design, snow cover and mixing, and its implications for accurately estimating methane emissions.

211 Analysis of microbial communities from a commercial-size swine manure pit and their association with production of volatile organic compounds

Abstract Global pollution and emission concerns have been linked to concentrated animal feeding operations (CAFOs). Indeed, the U.S Environmental Protection Agency (US EPA) warns that there is a significant danger to human health, soil, and water quality from CAFOs. Volatile organic compounds (VOCs), which are amongst air contaminants that pose a serious risk, are abundantly produced in swine manure pits. While VOC emissions from swine manure have been well studied, the microbial species responsible for their production remain mostly uncharacterized. Thus, a deeper comprehension of the microorganisms responsible for VOC production in swine manure pits may help in the development of management approaches that target the microbiome in these environments. In this context, this study aimed to identify the major bacterial species populating the manure pit of a commercial-size swine wean-to-finish research facility. Manure collected from two sampling locations at different time points were analyzed using the 16S rRNA gene through PCR-amplification of the V1-V3 regions from microbial genomic DNA, followed by Illumina MiSeq 2X300 sequencing. An analysis of the most highly represented microorganisms identified 24 bacterial Operational Taxonomic Units (OTUs), with only four showing a species-level nucleotide sequence identity to currently known or valid species. As these results indicated that the majority of bacterial species from this manure pit were unknown, a metagenomics approach was used to assemble partial to full length genomes from the two most abundant OTUs: Pit_9-00239 [5.09% - 19.44%; Clostridium saccharoperbutylacetonicum (96.60%)] and Pit_ 7-00035 [5.58% - 17.30%; Bacteroides eggerthii (87.66%)]. From genome assembly analysis, 979 contigs were generated for a combined length of 12,367,510 bp, which together included 21,776 coding sequences. Predicted metabolic functions from these contig sets included pathways involved in carbohydrate utilization (glycolysis), vitamin synthesis (riboflavin), and butyrate production (volatile fatty acids). Notably, an enzyme responsible for the production of indole, a common VOC produced from swine manure pits, was also identified. Together, the results from this analysis provide insights on metabolic capabilities of abundant bacterial species from manure pits. These can in turn be used for the future development of management strategies or products that can reduce VOC emissions that result from swine CAFO manure storage.

Improving Human Diets and Welfare through Using Herbivore-Based Foods: 2. Environmental Consequences and Mitigations.

Animal-sourced foods are important for human nutrition and health, but they can have a negative impact on the environment. These impacts can result in land use tensions associated with population growth and the loss of native forests and wetlands during agricultural expansion. Increased greenhouse gas emissions, and high water use but poor water quality outcomes can also be associated. Life cycle analysis from cradle-to-distribution has shown that novel plant-based meat alternatives can have an environmental footprint lower than that of beef finished in feedlots, but higher than for beef raised on well-managed grazed pastures. However, several technologies and practices can be used to mitigate impacts. These include ensuring that grazing occurs when feed quality is high, the use of dietary additives, breeding of animals with higher growth rates and increased fecundity, rumen microbial manipulations through the use of vaccines, soil management to reduce nitrous oxide emission, management systems to improve carbon sequestration, improved nutrient use efficacy throughout the food chain, incorporating maize silage along with grasslands, use of cover crops, low-emission composting barns, covered manure storages, and direct injection of animal slurry into soil. The technologies and systems that help mitigate or actually provide solutions to the environmental impact are under constant refinement to enable ever-more efficient production systems to allow for the provision of animal-sourced foods to an ever-increasing population.

Effect of composting and storage on the microbiome and resistome of cattle manure from a commercial dairy farm in Poland.

Manure from food-producing animals, rich in antibiotic-resistant bacteria and antibiotic resistance genes (ARGs), poses significant environmental and healthcare risks. Despite global efforts, most manure is not adequately processed before use on fields, escalating the spread of antimicrobial resistance. This study examined how different cattle manure treatments, including composting and storage, affect its microbiome and resistome. The changes occurring in the microbiome and resistome of the treated manure samples were compared with those of raw samples by high-throughput qPCR for ARGs tracking and sequencing of the V3-V4 variable region of the 16S rRNA gene to indicate bacterial community composition. We identified 203 ARGs and mobile genetic elements (MGEs) in raw manure. Post-treatment reduced these to 76 in composted and 51 in stored samples. Notably, beta-lactam, cross-resistance to macrolides, lincosamides and streptogramin B (MLSB), and vancomycin resistance genes decreased, while genes linked to MGEs, integrons, and sulfonamide resistance increased after composting. Overall, total resistance gene abundance significantly dropped with both treatments. During composting, the relative abundance of genes was lower midway than at the end. Moreover, higher biodiversity was observed in samples after composting than storage. Our current research shows that both composting and storage effectively reduce ARGs in cattle manure. However, it is challenging to determine which method is superior, as different groups of resistance genes react differently to each treatment, even though a notable overall reduction in ARGs is observed.

Complete elimination of methane formation in stored livestock manure using plasma technology

Plasma-based nitrogen fixation has recently been shown to be applicable in the domain of manure management, as it has the ability to reduce ammoniacal nitrogen losses and increase the nitrogen content of organic wastes, with air and electricity as the only input. In addition, the plasma treatment confers antimicrobial properties, which we hypothesize to be transferable to methanogenic archaea and hence prevent methane formation during manure storage – a major contributor to global anthropogenic greenhouse gas emissions. In this work we compared the methane formation from cow manure to the methane formation in nitrogen enriched cow manure, kept in two outdoor storage tanks for 70–80 summer days over three consecutive years. In all instances, the methane formation was eliminated completely. To investigate the cause of inhibition, a controlled incubation experiment was conducted to show that neither the acidification nor the addition of nitrate or nitrite, alone or in combination, could explain the inhibition of methanogenesis and denitrification that occurred in plasma treated cow manure at moderate pH.

Slurry acidification is as effective as slurry injection at reducing ammonia emissions without increasing N2O emissions: A short-term mesocosm study

Agriculture currently accounts for 90% of UK ammonia (NH3) emissions, however, national legally-binding targets are seeking to reduce this by 16% by 2030, relative to 2005 levels. One area which has been targeted to help achieve this target is the lowering of NH3 emissions during livestock manure handling and storage. Slurry acidification represents one potential strategy to abate NH3 throughout the slurry management chain, however, is not currently used in the UK. To address this knowledge gap, two mesocosm-scale experiments were set up to assess the potential for slurry acidification to reduce NH3 emissions at application and to measure impacts on NH3 emissions and short-term changes to soil mineral dynamics and N2O emissions. Experiment 1 determined the impacts of acidified cattle slurry (pH 6.5, 5.5, and 4.8) to conventional (non-acidified) slurry when simulating surface broadcasting. Experiment 2 assessed the impact of conventional and acidified slurry (pH 5.5) using simulated surface broadcasting and shallow injection of cattle slurry. Our results showed that acidification significantly abated NH3 (% of NH4-N applied) from 61.6% for conventional slurry to 26.6% at pH 5.5, and 2.5% at pH 4.8. Acidified surface broadcast was as effective at abating NH3 emissions to injected conventional slurry, and also delayed nitrification, while not significantly altering N2O emissions from conventional slurry. Our results strongly suggest that slurry acidification could be a viable strategy to help the UK reach its NH3 reduction target and exceed the current abatement potential through combining low emissions spreading techniques with acidification.