Cattle Feedlot Manure Research Articles

Energy Recovery Efficiency of Integrating Anaerobic Co-Digestion of Pig Slurry and Feedlot Cattle Manure and Hydrothermal Carbonization of Anaerobic Sludge Cake

Hydrothermal carbonization (HTC) is a technology designed to improve the efficiency of bioenergy recovery by subjecting biomass to high-temperature and high-pressure conditions. By integrating this technical feature with anaerobic digestion (AD), enhanced energy recovery efficiency is achieved in treating anaerobic digestate (AD-T). The study investigates enhancing bioenergy recovery efficiency through an integrated process, combining AD of livestock manure and HTC. The primary objective is to improve the energy conversion efficiency of biomass characterized by varying solid contents and chemical compositions. Shortening the hydraulic retention time (HRT) in AD of livestock manure resulted in decreased degradation rate efficiency within the AD-T. This led to increased solid material accumulation, which was crucial for the subsequent HTC reaction. The HTC reaction exhibited its maximum bioenergy recovery at 160 °C. The input energy of the livestock manure, obtained by mixing pig slurry and feedlot cattle manure in a 1:1 (w/w) ratio, was 171,167 MJ/day. Under different HRT conditions (40, 30, and 20 days), recoverable energy from AD of livestock manure ranged from 60,336 to 68,517 MJ/ton. Integration of HTC increased net bioenergy recovery to 106,493 to 130,491 MJ/day under corresponding HRT conditions, highlighting the potential of integrating HTC with AD from livestock manure for enhanced bioenergy recovery efficiency.

Material characterization and conditioning of cattle feedlot manure as feedstock for dry batch anaerobic digestion

The focus of the study was to determine the suitability of cattle feedlot manure originating from clay-pack feedlots as a possible feedstock material for dry batch anaerobic digestion. Oedometer tests were carried out that measure the permeability and compressibility of the feedstock under practical conditions experienced in large-scale dry batch anaerobic digestion plants. Material characterization tests showed that feedlot manure was impermeable under compression and therefore unsuitable for percolation. Mixtures of feedlot manure, wood chips (3 %ww) and wheat straw (6 %ww) showed superior permeability under compression compared to feedlot manure alone with an 56% increased permeability. Further practical tests showed that dry digestion of feedlot manure mixtures led to methane yields of 99 mL/g VS which equals 86% of the material biochemical methane potential (BMP). High percolation rate and low inoculum recycle led to the highest specific methane yield (SMY) and digester productivity with implications on process design to reduce capital investment costs.

Evaluation of Crop Recovery of Nitrogen from Lignite-amended Feedlot Cattle Manure

Feedlot cattle manures have for long been considered to be a major source of greenhouse gasses (GHG) in Australia. Lignite coals have been used recently as effective organic nitrification-inhibitors retaining nitrogen in cattle feedlot manure by reducing the emission of nitrogenous gases. This study is aimed at investigating whether lignite-retained nitrogen in cattle feedlot manure can be used as an available nitrogen (N) source for absorption by plants hence contribute to improved plant growth and produce higher yields.

Degradation of antimicrobial resistance genes within stockpiled beef cattle feedlot manure

Degradation of antimicrobial resistance genes (ARG) in manure from beef cattle administered (kg−1 feed) 44 mg of chlortetracycline (CTC), 44 mg of chlortetracycline plus sulfamethazine (CTCSMZ), 11 mg of tylosin (TYL), or no antimicrobials (Control) was examined. Manure was stockpiled and quantitative PCR (qPCR) was used to assess tetracycline [tet(C), (L), (M), (W)], erythromycin [erm(A), (B), (F), (X)], and sulfamethazine [sul(1), (2)] ARG and 16S rDNA. After 102 d, copies of all ARG decreased by 0.3 to 1.5 log10 copies (g dry matter)−1. Temperature in the interior of piles averaged ≥ 55 °C for 10 d, except for CTCSMZ, but did not reach 55 °C at pile exteriors. Compared to Control, CTCSMZ increased (P < 0.05) tet(C), tet(M), tet(W), sul(1), and sul(2) in stockpiled manure. Copies of 16S rDNA remained higher (P < 0.05) in CTCSMZ than Control for the first 26 d. Levels of most ARG did not differ between the interior and exterior of stockpiles. Our results suggest that stockpiled manure would still introduce ARG to land upon manure application, but at levels lower than if manure was applied fresh.

Impact of Feedlot Manure and Nitrogen Additions on Forage Yields, Nutrient Balance and Soil Nitrate, Phosphate and Salinity

ABSTRACT Safe disposal of feedlot manure is an increasing problem throughout the world. A field experiment was established on a duplex sandy loam soil (Alfisol) in Northern NSW, Australia to determine the dry matter (DM) crop response and the fate of nutrients derived from cattle feedlot manure and inorganic fertilizer applications. The five treatments imposed over a three year period were no manure or inorganic fertilizer (NM), a moderate annual manure application (20–25 t DM ha−1) -/+ N (MA, MAN) a high initial application in year 1 (60 t DM ha−1 + N, HIN) and an inorganic fertilizer treatment (single superphosphate, KCl, urea, I) applied in each year. Vegetative yields of forage sorghum (Sorghum bicolor cv. Super-Dan) and triticale (Triticosecale spp. cv. Madonna) were recorded in crops grown in sequence over a three-year period. A mass balance approach was used to quantify nutrient gains to, and losses from the system. Total crop yield was 14.22 t dry matter (DM) ha−1 in the NM treatment with an approximate threefold increase with HIN and I. Removal of nutrients (kg ha−1) in harvested forage was highest for N, K and S in the I treatment (767 N, 1447 K, 76 S) and highest for P in the HIN treatment (189 P). There was no accumulation of NO3 in the soil layers to the B horizon in the manure treatments which contrasts with I. In the manure treatments there was a 6 to 8 fold increase over the initial value in Colwell bicarbonate extractable P in the 0–10 cm soil horizon in the MAN and HIN treatments, a decline in exchangeable K, an increase in EC and a loss of P sorption capacity. Supplemental inorganic nitrogen has been found to increase the nutrient benefits of feedlot manure. Accumulation of soil phosphate and salts, and a decline in soil K was found and needs to be closely monitored to maintain productivity and the environment.

TOTAL CONTENT AND AVAILABILITY OF MICRONUTRIENTS IN SOILS AND LIVESTOCK MANURE

The use of feedlot cattle manure appears as an important source of certain trace metals in soils that can be mobilized by water modifying the surface and groundwater quality. The current study is focused on assessing the availability of copper (Cu), zinc (Zn), cobalt (Co) and molybdenum (Mo) in manure from confined beef cattle systems and different soils of the Chaco-pampean plain, using a sequential extraction scheme. Soils and bovine manure coming from intensive (IS) and extensive (ES) beef cattle systems were collected. Total contents of Cu, Zn, Co and Mo were determined after microwave assisted acid digestion. Availability was evaluated through sequential extraction, including water-soluble and exchangeable fraction (EXCH), organic matter bound fraction (OM), inorganic precipitated fraction (INOR), and residual fraction (RES). Total Cu and Zn contents found in manure coming from IS were higher than the concentration of the aforementioned trace elements determined in all soils and manure analyzed from ES. EXCH-Cu only appears in IS cattle manure samples, while EXCH-Zn found in IS manure samples were higher than the soils samples analyzed. The higher levels of total and availability forms of Cu and Zn determined in IS manure compared to soils samples, require considering when this organic amendment is applied as fertilizer. These results indicate that the reuse of intensive cattle manure as fertilizer in agricultural areas could provide available forms of metals in soils and could contribute to reduce the environmental impact caused by the accumulation of excreta in pen soils during long periods in farms.

Phosphorus speciation and bioavailability in diverse biochars

Erosion of phosphorus (P)-rich soil into waterways is a major contributor to eutrophication. To minimize the build-up of P in agricultural soils, greater knowledge of the bioavailability and fate of P from soil amendments is required. We used X-ray Absorption Near Edge Structure (XANES) spectroscopy to resolve the major P species in nine diverse biochars. We then examined the relationship between biochar P extracted using a range of typical soil (water, Bray2 and Colwell) and plant (2% citric acid, and 2% formic acid) assays. We compared these with ryegrass P uptake via bioassay. Linear combination fitting indicated Al-phosphate (variscite) was the dominant P species in biochars derived from cattle feedlot manure, sugarcane trash and sugarcane bagasse, reflecting the likely Al content of the feedstock. Non-apatite Ca-phosphates (monocalcium phosphate or CaHPO4) were the major P species in poultry litter, green waste, papermill sludge, wheat chaff, sugarcane mill mud and rice husk biochars. Biochar P was poorly water soluble but largely soluble in weak acids (formic and citric acids). Despite this, biochar P extracted by citric and formic acid was a poor predictor of P bioavailability to ryegrass, with the percentage of total P extracted by water or by the Bray2 reagent providing the best prediction of ryegrass P uptake. The P in biochar was identified by XANES spectroscopy as predominantly Ca and/or Al-P. Water and Bray2 extraction provided the best predictors of plant available P from biochars in a plant bioassay.

Phytoextraction of nitrogen and phosphorus by crops grown in a heavily manured Dark Brown Chernozem under contrasting soil moisture conditions

ABSTRACTPhytoextraction of excess nutrients by crops in soils with a long history of manure application may be a viable option for reducing the nutrient levels. This greenhouse study examined the effectiveness of six growth cycles (40 d each) of barley, canola, corn, oat, pea, soybean, and triticale at extracting nitrogen (N) and phosphorus (P) from a Dark Brown Chernozem that had received 180 Mg ha−1 (wet wt.) of beef cattle feedlot manure annually for 38 years. Moisture content during the study was maintained at either 100% or 50% soil field capacity (SFC). Repeated cropping resulted in an overall decrease in dry matter yield (DMY). The decrease in N and P uptake relative to Cycle 1 was fastest for the cereal grains and less pronounced for the two legumes. However, cumulative N uptake values were significantly greater for corn than the other crops under both moisture regimes. The reduction in soil N was greater under the 100% than the 50% SFC. These results indicate that repeated cropping can be a useful management practice for reducing N and P levels in a heavily manured soil. The extent of reduction will be greater for crops with high biomass production under adequate moisture supply.

Experimental investigation of biogas production from feedlot cattle manure

Biogas can be generated from biomass in an anaerobic digestion process and used to generate electricity and heat as an alternative energy source to fossil fuel-generated electricity. This study investigated biogas generation from cattle manure dried for periods up to 40 days. Manure samples were analysed for gas yield using the biochemical methane production test. The biogas volume produced by manure samples aged for periods up to 40 days after seeding with cattle rumen fluid was measured as a function of time until there was no further measurable gas production. The biogas was analysed for methane and carbon dioxide content using a gas chromatograph. The corresponding cumulative net biogas yield ranged from 154 to 369 Nml/g.VS respectively. The test results showed that an average of 240 Nml/g.VS of biogas can be produced from cattle manure that is less than 40 days old, with an average methane and carbon dioxide percentage of 63% and 31% respectively. Within 3 to 4 days the manure samples generated 80% of the final biogas volume. The drying process was found to occur at a constant rate per unit area, regardless of the manure thickness up to thickness of 200 mm. Biogas formation closely followed the Gompertz equation. There was no significant difference in the biogas production nor biogas production rate for cattle feedlot manure that was fresh up until aging to 40 days.

Temporal Nitrous Oxide Emissions from Beef Cattle Feedlot Manure after a Simulated Rainfall Event.

Nitrous oxide (NO) is a greenhouse gas (GHG) emitted from agricultural operations. The objective of this research was to quantify NO-N emissions from simulated open-lot beef cattle feedlot pens after rainfall. A recirculating-flow-through, non-steady state chamber system consisting of five 1-m steel pans was designed for quantifying emissions. A lid was placed sequentially on each pan, and headspace air was recirculated between the pan and a real-time NO analyzer, measuring concentrations every 1 s. Air-dried manure (89.2% dry matter) from a commercial feedlot in the Texas Panhandle was placed in the pans and then 0, 6.3, 12.7, 25.4, or 50.8 mm of water was applied to simulate a one-time rainfall event. Emissions of NO-N were monitored for 45 d, where two distinct episodes of NO-N production were observed over time. The first NO-N episode had a duration of 10 h and peaked 2 h after rainfall at a flux of 1.0 to 200 mg m h. The second episode had a duration of 40 d and peaked 15 d after rainfall at a flux of 0.06 to 35 mg m h. The second episode accounted for 69 to 91% of the cumulative NO-N emitted over the 45-d period. Each millimeter of rainfall increased cumulative NO-N emitted by 167.9 mg m ( = 0.99, < 0.001). This rainfall vs. cumulative emissions relationship will be useful for modeling annual NO-N emissions from open-lot beef cattle feedlots, and for assessing the effectiveness of best management practices for reducing feedlot GHG emissions.

Greenhouse gas emissions during co-composting of cattle feedlot manure with construction and demolition (C&amp;D) waste

Manure management strategies should reflect current animal feeding practices and encourage recycling of organic waste to help protect our environment. This research investigated greenhouse gas (GHG) emissions during cattle manure stockpiling or composting with and without construction and demolition (C&D) waste. Manure was collected from cattle fed a typical finishing diet (CK manure) and from cattle on diets which included 30%dried distillers grains with solubles (DG manure). The CK and DG manures were co-composted with (4:1) C&D waste (treatments: CK_CD, DG_CD), composted alone (treatments: CK and DG) in 13 m3 bins or stockpiled without C&D waste (treatments: CK_ST and DG_ST) for 99 days. Manure type (CK vs. DG manure) had no effect on GHG emissions over the 99 day manure composting or stockpiling. Composting with C&D waste produced similar CO2 emissions, about double that from manure stockpiling (7.0 kgC•m–2). In contrast, CH4 emissions were reduced by the inclusion of C&D waste (64 gC•m–2 with C&D vs. 244 gC•m–2 without C&D) while the manure stockpile emitted the greatest amount of CH4 (464 gC•m–2). Additionally, only 0.48% of C was emitted in CH4 form with C&D waste, compared to 1.68% when composting without C&D waste and 7.00% when cattle manure was stockpiled. The N2O emissions (12.4 to 18.0 gN•m–2) were similar across all treatments. The lower CH4 emissions with C&D waste are beneficial in reducing overall GHG emissions from manure composting, while reducing the amount of material entering landfills.

Anaerobically Digested Cattle Manure Supplied More Nitrogen with Less Phosphorus Accumulation than Undigested Manure

Core Ideas Barley recovered 19% of N applied by anaerobically digested cattle manure over 4 yr. Barley recovered 10% of N applied by undigested cattle manure over 4 yr. Separated solids and cattle manure supplied similar amounts of N and P to barley. Pelletized separated solids released N too slowly for a barley yield benefit. Separated solids posed a greater risk of P accumulation than cattle manure. Solid beef cattle manure is a good anaerobic digestion feedstock for methane production, but more research is needed to determine how co‐products of the anaerobically digested manure may be used in crop production, while limiting the risk of nutrient loss to the environment. Over four growing seasons, we measured the N and P supplied to barley (Hordeum vulgare L.) forage test crops from (i) anaerobically digested solid beef cattle manure (digestate), (ii) separated solids from the digestate (separated solids), (iii) pelletized separated solids (pellets), and (iv) undigested solid beef cattle manure (manure) that were applied to target 1× (260 kg N ha−1) and 2× (520 kg N ha−1) the recommended N rates. Non‐amended soil was the control. Digestate led to 31 to 50% greater barley forage yield than the other amendments. The apparent N recovery from digestate (19%) was much greater than pellets (2%) and about double that of the separated solids (9%) and cattle manure (10%). The barley N uptake derived from digestate was 41%, which was significantly greater than manure (22%), separated solids (17%), and pellets (2%). Digestate increased P uptake, while significantly reducing soil‐test P accumulation compared with the other co‐products and cattle manure when applied at N‐based rates. Our results confirmed that management practices for solid beef cattle feedlot manure may be used for separated solids, but not digestate. Pelletized separated solids may be an effective slow release fertilizer, while also supplying C, but determination of its nutrient release patterns is required.

Agronomic Values of Anaerobically Digested Cattle Manure and the Separated Solids for Barley Forage Production

Core Ideas Agronomic values of anaerobically digested solid cattle manure are poorly defined. Separated solids of anaerobically digested cattle manure supplied N similar to cattle manure. Anaerobically digested cattle manure had high NH4–N/total N ratio. Anaerobically digested cattle manure had less P buildup than cattle manure. Digestate separated solids can be managed similar to cattle manure. As biogas production expands, digestates from that industry are increasingly available as potential nutrient sources for crop production, but their agronomic value is poorly understood. Thus, a 5‐yr field experiment was conducted to determine the agronomic values of anaerobically digested solid beef cattle feedlot manure (ADM) and the separated solids (SS) from ADM under a semiarid reduced‐tillage dryland barley (Hordeum vulgare L.) forage cropping system. Three organic amendments, ADM, SS, and undigested solid beef cattle feedlot manure (CM), were applied annually at 200 or 400 kg total N ha−1 for 4 yr, while the residual effect was examined in the fifth year. The higher N and P availability in ADM translated into greater barley forage yields, total N uptake, amendment‐derived N uptake, and apparent N recovery (ANR) from ADM‐amended soil than SS‐ and CM‐amended soils, while there were no significant differences between soils receiving SS or CM. The ANR was 22% for ADM but only 12% for CM and 9% for SS. In contrast, P uptake, the fraction of amendment‐derived P uptake, and apparent P recovery were similar among all amendments. Similar yields, ANR, post‐harvest soil NH4, NO3, and Olsen‐P concentrations between SS‐ and CM‐amended soils suggest that they have a comparable agronomic value. Less residual Olsen‐P in soil receiving ADM than SS or CM suggests that ADM is a lower risk for P accumulation when applied at N‐based rates. We recommend that current agronomic values for cattle feedlot manure could be applied to SS but not ADM.

1187 Effect of temperature on ammonia emissions from feedlot cattle manure

1187 Effect of temperature on ammonia emissions from feedlot cattle manure

Utilizing Composted Beef Cattle Manure and Slaughterhouse Waste as Nitrogen and Phosphorus Fertilizers for Calcareous Soil

ABSTRACTEffectively utilizing composts requires that their nitrogen (N) and phosphorus (P) contents be used as fertilizer, but how this is best accomplished is not fully understood. The authors' objective was to quantify N and P availability of a calcareous clay loam soil receiving composts derived from four contrasting beef cattle feedlot feedstocks applied at 50, 150, and 450 mg total P kg−1 and supplemented twice with fertilizer N for a 42-week greenhouse plant bioassay. Three composted manures from beef cattle fed distinct diets and a composted mix of slaughterhouse and construction waste were applied. Inorganically fertilized and non-amended soils were included as controls. Canola (Brassica napus L.) and pea (Pisum sativum L.) were grown in pots containing 1.5 kg air-dried soil for six alternating 7-week cycles. Soils amended with composted manure from beef cattle fed typical finishing diets had the lowest apparent N recovery (31%) and the greatest soil nitrate after 42 weeks (25 mg N kg−1). Phosphorus availability was greater with composted manure from beef cattle fed distillers' dried grains than composted manure from beef cattle fed typical finishing diets and a composted mixture of slaughterhouse and construction waste. Apparent P recovery (66%) was greatest from composted manure of beef cattle fed corn (Zea mays L.) distillers' dried grains applied at 50 mg total P kg−1. Composted manure from beef cattle fed distillers' dried grains had greater P availability than conventional composted beef cattle feedlot manure. Overall, performance of the composted mixture of slaughterhouse and construction waste was similar to the composted beef cattle manures.

Performance of four stabilization bioprocesses of beef cattle feedlot manure

The biological stabilization of beef cattle manure is crucial for promoting sanitation in feedlot pens. This study compared the performance of composting, vermicomposting, static windrows, and anaerobic digestion for stabilization of beef cattle feedlot manure based on the degradation of organic matter, nutrient retention, and stability of the final product in each process using uni- and multivariate analysis. The cluster analysis showed that composting and vermicomposting were the most similar processes. The principal component analysis showed that the more oxidative processes (composting and vermicomposting) degraded beef cattle feedlot manure more effectively (up to 45%) than static windrows and anaerobic digestion. Stabilization processes did not affect the amount of phosphorus, whereas potassium losses ranged from 3% (anaerobic digestion) to 30% (static windrow) and differed significantly across processes. Electrical conductivity decreased only in static windrow (30%). A decrease in the C/N ratio were observed in all processes, but the reduction was smaller in static windrow (5%). Larger reductions in C/N ratio were associated with greater increases in the humic to fulvic acid ratio. Composting and vermicomposting processes more effectively degraded beef cattle manure and produced stable organic fertilizers. Anaerobic digestion more effectively retained macronutrients (N and K) and converted organic N to ammonium. The use of static windrows is the least effective bioprocess for the stabilization of beef cattle feedlot manure.

Inactivation of Bacillus anthracis Spores during Laboratory-Scale Composting of Feedlot Cattle Manure.

Anthrax outbreaks in livestock have social, economic and health implications, altering farmer’s livelihoods, impacting trade and posing a zoonotic risk. Our study investigated the survival of Bacillus thuringiensis and B. anthracis spores sporulated at 15, 20, or 37°C, over 33 days of composting. Spores (∼7.5 log10 CFU g-1) were mixed with manure and composted in laboratory scale composters. After 15 days, the compost was mixed and returned to the composter for a second cycle. Temperatures peaked at 71°C on day 2 and remained ≥55°C for an average of 7 days in the first cycle, but did not exceed 55°C in the second. For B. thuringiensis, spores generated at 15 and 21°C exhibited reduced (P < 0.05) viability of 2.7 and 2.6 log10 CFU g-1 respectively, as compared to a 0.6 log10 CFU g-1 reduction for those generated at 37°C. For B. anthracis, sporulation temperature did not impact spore survival as there was a 2.5, 2.2, and 2.8 log10 CFU g-1 reduction after composting for spores generated at 15, 21, and 37°C, respectively. For both species, spore viability declined more rapidly (P < 0.05) in the first as compared to the second composting cycle. Our findings suggest that the duration of thermophilic exposure (≥55°C) is the main factor influencing survival of B. anthracis spores in compost. As sporulation temperature did not influence survival of B. anthracis, composting may lower the viability of spores associated with carcasses infected with B. anthracis over a range of sporulation temperatures.

Managing the value of composts as organic amendments and fertilizers in sandy soils

Nutrient rich composts are employed at low rates to minimize risks of N and P losses; this limits their value as soil improvers through C addition and the build up of soil organic matter. Blending with nutrient-poor composts such as those from the organic fraction of municipal solid waste could reduce the risks of nutrient losses while maintaining the positive effects on soil organic matter. We conducted a 2-yr experiment with composts of diverse origin: organic fraction of municipal solid waste (MC), cattle feedlot manure (FC), poultry litter (PC) and biosolids (BC), alone or blended (FC-MC, PC-MC) in a sandy soil under the humid warm climatic conditions of NE Argentina. We studied the effects of a single application (40 Mg ha−1) on the surface soil (0–10cm) properties of a permanent subtropical pasture through annual chemical and biological analyses. On five dates, available N and P were also determined at 0–10cm and 55–65cm. Soil total C and N increased over time while potential N mineralization and CO2 emission decreased. All amendments resulted in similar increments of soil C and N despite marked differences in quantity and quality of organic matter inputs. Because MC had substantial amounts of Ca carbonates, it contributed to a reduction of available P from manure composts through dilution and precipitation. The release of available P from biosolids composts (where P is bound to Fe and Al) was lower than from manure composts (where P is bound by Ca phosphates). The highest environmental risk from compost application would likely be the leaching of soluble N produced during the composting process and released immediately after field application. Blending with N-poor MC would contribute to nitrate dilution.

Residual Effects of Novel versus Traditional Organic Amendments for Rain-fed No-till Barley: Yield, Nutrient Uptake, and N2O Emissions

ABSTRACTOrganic amendments recycle nutrients, but N2O emissions are both environmental and agronomic concerns. We conducted a 4-year field experiment to determine no-till barley (Hordeum vulgare L.) yield and nutrient uptake and soil N2O emissions following a single application of six amendment treatments: (1) no amendment (Check); (2) synthetic N fertilizer (Fert); (3) fresh beef cattle feedlot manure (ManureF); (4) beef cattle feedlot manure compost (CompostR); (5) beef cattle feedlot manure composted with cattle mortalities (CompostM); and (6) separated solids from anaerobically digested cattle feedlot manure (ADM). Barley grown in Year 1 (2006), Year 2 (2007), and Year 4 (2009) (with Year 3 (2008) under fallow) had higher grain yields from ManureF (4.73 Mg ha−1) in Year 2 and ADM (6.30 Mg ha−1) in Year 4 (p < 0.05) than other treatments. The grain N and P contents were not affected (p > 0.05), but N uptake over 3 years (112.8 kg N ha−1 yr−1), and P uptake in Year 1 (19.1 kg ha−1 yr−1) and Year 2 (14.3 kg ha−1 yr−1) from ManureF, were higher (p < 0.05×) than other treatments. The cumulative N2O emissions from ManureF in Year 1 (1.488 kg N ha−1) and from ADM in Year 2 (1.072 kg N ha−1) were higher (p < 0.05) than other treatments while the fraction of applied N emitted as N2O was small (0.00 to 0.79%) and not affected by treatment. However, the percentages of applied N emitted as N2O from compost and ADM were similar to synthetic fertilizer and livestock manure.

The Bioenergy Conversion Characteristics of Feedlot Manure Discharging from Beef Cattle Barn

This study was carried out to assess bioenergy conversion efficiency by biogas and solid fuel production in the cattle feedlot manure discharged from beef cattle barn. Feedlot manure was sampled from the cattle farmhouse located in Yong-in, Gyeonggi during the mid-fattening stage, periodically. The chemical characteristics, BMP (Biochemical methane potential) and HV (Heating values) of feedlot cattle manures were analyzed. Total solid contents of cattle feedlot manure were in the range of 29.98~44.28%, and volatile solid contents were in the range of 23.53~24.47%. In the anaerobic digestion of cattle feedlot manure, the methane production potential has increased from 0.141 to 0.187 Nm 3 kg -1 -VS added . The methane production of fresh cattle feedlot manure showed the range 0.141~0.187 Nm 3 kg -1 -Manure (average 0.047 Nm 3 kg -1 -Manure), the LHVs (lower heating values) of the produced methane were in the range of 316~560 kcal kg -1 -Manure (average 400 kcal kg -1 - Manure). In the direct combustion of fresh cattle feedlot manure, the LHVs were measured in the range of 747~1,271 kcal kg -1 -Manure (average 916 kcal kg -1 -Manure), and LHVs of solid fuel which have the water content of 20% were in the range of 2,694~2,876 kcal kg -1 -Manure (average 2,791 kcal kg -1 -Manure). Then, the drying energy of average 443 kcal kg -1 -Manure was consumed in the production of solid fuel which has a water content of 20%. Therefore, the direct combustion of cattle feedlot manure showed about 2.3 times higher LHV than the LHV of methane produced by anaerobic digestion. And LHV of solid fuel was about 6.0 times higher than the LHV of methane produced by anaerobic digestion. Then, the production of solid fuel presented more bioenergy conversion efficiency than the biogas production in the bioenergy use of cattle feedlot manure.