Swine Manure Research Articles

Wheat straw biochar as an additive in swine manure Composting: An in-depth analysis of mixed material particle characteristics and interface interactions

In recent research, biochar has been proven to reduce the greenhouse gases and promote organic matter during the composting. However, gas degradation may be related to the microstructure of compost. To investigate the mechanism of biochar additive, composting was performed using swine manure, wheat straw and biochar and representative solid compost samples were analyzed to characterize the mixed biochar and compost particles. We focused on the microscale, such as the particle size distributions, surface morphologies, aerobic layer thicknesses and the functional groups. The biochar and compost particle agglomerations gradually became weaker and the predominant particle size in the experiment group was < 200 μm. The aerobic layer thickness (Lp) was determined by infrared spectroscopy using the wavenumbers 2856 and 1568 cm−1, which was 0–50 μm increased as composting proceeded in both groups. The biochar increased Lp and facilitated oxygen penetrating the compost particle cores. Besides, in the biochar-swine manure particle interface, the aliphatic compound in the organic components degraded and the content of aromaticity increased with the composting process, which was indicated by the absorption intensity at 2856 cm−1 decreasing trend and the absorption intensity at 1568 cm−1 increasing trend. In summary, biochar performed well in the microscale of compost pile.

Pathways to sustainable transitions in a complex agricultural system: a case study of swine waste management in North Carolina

North Carolina has a high density of swine farms with nearly half of the commercial operations located in two eastern counties. Lagoon and sprayfield (LS) is the dominant method of swine manure management despite pressure to transition to environmentally superior technologies. LS is an efficient and cost-effective method of waste management but has negatively impacted the environment and local communities from both discreet events (breeches, flooding) and ongoing issues (odor, disease vectors). The Multilevel Perspective Theory (MLP) is a frame for understanding the relationships between a sociotechnical regime, its surrounding landscape, and emerging niches for sustainable technology development to help align these different levels of perspective and support transitioning toward more sustainable practices. Here, a farm level is added to represent the user perspective of regime technology in complex agriculture systems (MLP + F). We demonstrate how change may influence the North Carolina swine waste management (NC SWM) system through alternative scenarios applied to a conceptual model developed with the MLP + F frame in a methodology for analyzing complex agricultural systems with input from a diverse panel of experts. This case study demonstrates how the methodology can be applied through two NC SWM model scenarios analyzed with fuzzy cognitive mapping techniques. The first scenario explores whether panel recommended changes generate a shift toward sustainable manure management. Inference results suggest that experts have a broad understanding of how these goals may be achieved, but strategies are needed to enhance the specificity of proposed changes. Testing scenarios with more targeted interventions within specific subsystems could provide greater guidance with regard to policy, economic factors, farm practices, or societal demands. The second scenario considers the systemic effect of introducing a manure dewatering process on swine operations, with and without landscape support. Results from this scenario indicate that the more landscape support is engaged, the greater the impact on desirable outcomes. However, contradictions emerged between different versions of this scenario such as increased negative public perceptions despite positive community outcomes. This may require further investigation to tease out potential misalignment between perceptions of a complex system and actual system behaviors.

Waste Sludge: Entirely Waste or a Sustainable Source of Biocrude? A Review.

Biomass-derived biocrude is gaining greater recognition from people in general as an alternative fuel source to traditional fossil fuels. Worldwide, a great deal of research is being done to develop fuels made from sustainable biomass in order to replace the current conventional energy sources. Waste sludge has been thought of as a viable raw biomass source because of its accessibility, affordability, high lignin content, and higher heating value. Additionally, considering sludge contains a high proportion of moisture and water acts as a catalyst during the hydrothermal liquefaction (HTL) process, it is the best choice for thermochemical conversion. From the ultimate component value ranges obtained from elemental analysis, it can be demonstrated that the C, H, and higher heating value (HHV) of petrocrude are approximately 8.78%, 23.5%, and 10.66% higher than those of biofuel. According to the overall analysis, co-liquefaction of waste vegetable oil and swine manure can result in 87.97% bio-oil at 340°C. The temperature, retention period, inclusion of catalysts, and use of solvents, however, can all affect this proportion. To support this illustration, it has been assessed from the study that municipal wet sewage sludge can produce an HHV of 28.52MJ/kg when water is used as the solvent. However, 34.14MJ/kg, or 16.5% more than the previous one, can be produced for the same amount of biomass, when the mixture of water and methanol serves as the solvents. This review article highlights an array of waste sludge categories, their chemical properties, and their conversion through the HTL process. It also features a Van Krevlen diagram with a graphical representation of essential operating parameters. This review research illustrates one of the best strategies for producing biofuel in which waste sludge can be used as raw material through the HTL conversion process, considering the prospective mass commercial production of biocrude oil.

Chemical looping with oxygen uncoupling of swine manure for energy production with reduction of greenhouse gas emissions

The thermochemical conversion of swine manure using chemical looping processes is an alternative for obtaining bioenergy with CO2 capture and solving environmental problems related to excess nutrients and greenhouse gas emissions. In this study, the combustion of swine manure was performed in a chemical looping with oxygen uncoupling (CLOU) unit at the 0.5 kWth scale with copper-based oxygen carrier particles supported on magnetic MnFe spinel. The effects of the fluidisation agent (CO2 or steam), air excess (7%–23%), and temperature (800–950 °C) on different parameters, namely the CO2 capture rate, combustion efficiency, and nitrogenous compound emissions, were analysed. High combustion efficiencies (95%–98%) were achieved, and tar compounds were not detected in the flue gases. Similarly, elevated CO2 capture efficiency values (82%–99%) were also achieved, which increased by increasing the temperature. Most nitrogen (ca. 93%–96%) is converted into innocuous N2. The NO concentration increased with temperature, whereas N2O and NH3 concentrations decreased.

Study of two approaches for the process water management from hydrothermal carbonization of swine manure: Anaerobic treatment and nutrient recovery

Hydrothermal carbonization (HTC) is a promising alternative to transform biomass waste into a solid carbonaceous material (hydrochar) and a process water with potential for material and energy recovery. In this study, two alternatives for process water treatment by conventional and acid-assisted HTC of swine manure are discussed. Process water from conventional HTC at 180 °C showed high biodegradability (55% COD removal) and methane production (∼290 mL STP CH4 g−1 CODadded) and the treatment in an upflow anaerobic sludge blanket reactor allowed obtaining a high methane production yield (1.3 L CH4 L−1 d−1) and COD removal (∼70%). The analysis of the microbiota showed a high concentration of Synergistota and Firmicutes phyla, with high degradation of organic nitrogen-containing organic compounds. Acid-assisted HTC proved to be a viable option for nutrient recovery (migration of 83% of the P to the process water), which allowed obtaining a solid salt by chemical precipitation with Mg(OH)2 (NPK of 4/4/0.4) and MgCl2 (NPK 8/17/0.5), with a negligible content of heavy metals. The characteristics of the precipitated solid complied with the requirements of European Regulation (2019)/1009 for fertilizers and amendments in agricultural soils, being a suitable alternative for the recycling of nutrients from wastes.

Intramuscular therapeutic doses of enrofloxacin affect microbial community structure but not the relative abundance of fluoroquinolones resistance genes in swine manure

Livestock manure is a major source of veterinary antibiotics and antibiotic resistance genes (ARGs). Elucidation of the residual characteristics of ARGs in livestock manure following the administration of veterinary antibiotics is critical to assess their ecotoxicological effects and environmental contamination risks. Here, we investigated the effects of enrofloxacin (ENR), a fluoroquinolone antibiotic commonly used as a therapeutic drug in animal husbandry, on the characteristics of ARGs, mobile genetic elements, and microbial community structure in swine manure following its intramuscular administration for 3 days and a withdrawal period of 10 days. The results revealed the highest concentrations of ENR and ciprofloxacin (CIP) in swine manure at the end of the administration period, ENR concentrations in swine manure in groups L and H were 88.67 ± 45.46 and 219.75 ± 88.05 mg/kg DM, respectively. Approximately 15 fluoroquinolone resistance genes (FRGs) and 48 fluoroquinolone-related multidrug resistance genes (F-MRGs) were detected in swine manure; the relative abundance of the F-MRGs was considerably higher than that of the FRGs. On day 3, the relative abundance of qacA was significantly higher in group H than in group CK, and no significant differences in the relative abundance of other FRGs, F-MRGs, or MGEs were observed between the three groups on day 3 and day 13. The microbial community structure in swine manure was significantly altered on day 3, and the altered community structure was restored on day 13. The FRGs and F-MRGs with the highest relative abundance were qacA and adeF, respectively, and Clostridium and Lactobacillus were the dominant bacterial genera carrying these genes in swine manure. In summary, a single treatment of intramuscular ENR transiently increased antibiotic concentrations and altered the microbial community structure in swine manure; however, this treatment did not significantly affect the abundance of FRGs and F-MRGs.

THE INFLUENCE OF FERTILIZER TYPE AND Trichoderma harzianum INOCULATION ON THE GROWTH AND PHYSIOLOGY OF YOUNG PLANTS OF Cordia americana

In this study, we sought to determine the influence of combined treatments with different types of fertilizer and inoculation of the fungus Trichoderma harzianum on the growth and physiological characteristics of young plants of Cordia americana. To this end, we adopted a completely randomized experimental design, comprising six replications in a 5 × 2 factorial scheme, to assess the effects of five different types of fertilizer applied with or without T. harzianum inoculation. At 180 days post-planting, we performed measurements of plant height, stem diameter, leaf dry mass, root dry mass, stem dry mass, total dry mass, leaf area, Falker’s chlorophyll index, and chlorophyll fluorescence. It was found that the combined application of T. harzianum and a controlled-release fertilizer or manure-based organominerals was effective in enhancing the growth of C. americana plants under conditions similar to those in the field. The use of controlled-release fertilizer as a base fertilization was found to have a positive influence on all evaluated variables and was effective in maximizing the initial development of C. americana plants. Granulated fertilizers derived from swine manure were established to promote plant growth and photosynthetic efficiency, thereby confirming their efficacy as a fertilizer for the cultivation of C. americana.

Exploration of Alternatives to Reduce the Gap in Access to Electricity in Rural Communities—Las Nubes Village Case (Barranquilla, Colombia)

The global crisis associated with COVID-19 and the Russia-Ukraine conflict has affected progress towards the Sustainable Development Goals (SDGs). Projections for SDG7 (Ensure access to affordable, reliable, sustainable, and modern energy for all) indicate a slowdown in the pace of electrification. Thus, the problem of poverty will persist in many regions as long as access to electricity remains difficult. This work analyzes some solutions to the lack of electricity supply in a rural community using organic waste from its economic activity and the integration of other available renewable sources to make electricity affordable and reliable. A model that minimizes the levelized cost of energy and restricts the proportion of annual energy not supplied to less than 5% of the community’s annual demand optimizes the performance of off-grid and on-grid systems. These systems have in common the production of electricity from biogas produced from swine manure, supplemented with wind and solar generation. Batteries and diesel generators support the operation of off-grid systems. As expected, the grid-connected system presented the best performance; however, the result reaffirms the need for governments to ensure the policy and infrastructure conditions that facilitate the grid connection of vulnerable communities to achieve SDG7.

Odor generation pattern of swine manure according to the processing form of feed.

Feed has a great influence on the composition of swine manure, which is the principal cause of odor. Therefore, the purpose of this study is to simply change the shape of pig feed and control calories to find a suitable feed form for reducing the smell of swine manure. The experiment was conducted on 15 pigs from July to August 2021, and a total of three measurements were done. Three types of feed were evaluated in this study. The analysis items related to odor of swine manure are complex odor, ammonia, sulfur-based odors, and volatile organic compounds (VOCs). In the case of complex odor, dilution multiples tended to decrease over time, except for type A feed. The concentration of ammonia in all types of feed decreased over time. Most sulfur-based odorous substances except hydrogen sulfide at the first measurement were not detected. Representatively, Decane, 2,6-Dimethylnonane, and 1-Methyl-3-propylcycolhexane were detected in VOCs generated from swine manure. The major odorous substansces in swine manure have changed from ammonia and sulfur compounds to VOCs. In order to reduce the odor caused by swine manure, it is ad-vantageous to use low-calorie feed consisting of pellet-type.

Transport of Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes Through Prairie Strips During Simulated Runoff

HighlightsA physical model system was used to track resistance contaminants through prairie strips.Resistance contaminants included antibiotics, antibiotic-resistant bacteria, and antibiotic resistance genes.Subsurface filtration caused the highest concentration reduction of resistance contaminants.Infiltration is highlighted as a key feature in concentration and mass load reductions.Abstract. Antibiotic use in production animals can drive the development and spread of antibiotic resistance within environmental systems. Transport pathways of resistance contaminants from animals to the environment are known, but there is no regulatory consensus on which specific contaminants should be monitored. Furthermore, there is a need for management practices to combat the transport of these resistance contaminants. The objective of this study was to evaluate Conservation Practice 43 prairie strips for their reduction of three resistance indicators: antibiotics, antibiotic-resistant bacteria, and antibiotic resistance genes, from manure-impacted overland flow under varying run-on flow rates. High, medium, and low run-on flow rates were tested with the use of a laboratory-scale flume containing a field-extracted section of prairie strip. Grab samples were collected immediately upstream, downstream, and beneath the prairie strip, representing run-on, runoff, and infiltrated flows, respectively. Percent reductions in the median concentration of each resistance contaminant were calculated for each flow experiment at both the runoff and infiltration sampling locations to demonstrate the impact of the prairie strip. However, in instances where an increase in the median concentration of a contaminant occurred between the run-on sampling location and either the runoff or infiltration sampling locations, a negative percent reduction is reported. Across all flows, the percent reductions in median concentrations at the runoff sampling location ranged from -11.4%–0.8% for antibiotics, 1.2%–28.2% for bacteria, and -4.2%–30.5% for genes. In comparison, the percent reductions in median concentrations at the infiltration sampling location ranged from -23.9%–43.6% for antibiotics, 12.9%–65.5% for bacteria, and -12.6%–43.5% for genes. The dataset from this study supports the use of appropriately designed prairie strips to decrease the concentrations and loads of resistance contaminants that are transported downstream from manured fields and can be used to inform in-field design parameters. Keywords: Antibiotic resistance, Flume, Swine manure, Water quality.

The Nutrient Profile of Processed and Unprocessed Maggot Meal from Three Substrates

The proximate composition of housefly larvae (Musca domestica) maggot meal produced from a four (4) days old larvae raised in a mixture of three substrates: cow manure + cow blood (CMM), swine manure + cow blood (SMM), and poultry manure + cow blood and harvested on day 4 were determined. Harvested maggots were oven-dried at constant temperature (90o c) at different time regimes (35minutes, 45minutes, and 55minutes). Each treatment was named according to the substrate source and processing time: (CMM35, CMM45, CMM55, SMM35, SMM45, SMM55, PMM35, PMM45, PMM55). Results revealed that maggot meal contains 35.95-43.62% crude protein, fat ranged between 8.00-16.86%; Ash content ranged between 5.82-9.30%; crude fibre was between 1.15-2.91%, Moisture content was between 2.00-8.80% and nitrogen free extract (NFE) ranged between 29.2- 45.74%. Amino acids analysis identified 19 amino acids including 10 essential amino acids (EAA). The amino acids in CMM, SMM, PMM include: arginine, valine, lysine, methionine, leucine, isoleucine, histidine, tryptophan, phenylalanine, threonine, alanine, aspartate, glutamate, glycine, tyrosine, cysteine, proline serine and asparagine. The methionine content in the meals ranged between 3.78- 4.66 g/100g protein. The treatment CMM55 recorded the highest level of methionine (4.66 g/100g protein) compared to 2.49 g/100g protein in fishmeal. The crude protein of maggot meal is maximized if with poultry manurederived maggot meal that is oven processed for 55 minutes (43.62%).

Novel perspective on qualitative assessment of swine manure compost maturity using organic carbon density fractions

Mature compost is safe and stable, yet quality assessments are challenging owing to current maturity indicators’ limitations. This study employed density fractionation to separate organic carbon into light and heavy fractions, offering a new perspective for assessing maturity. Results showed that light fraction organic carbon progressively transitioned into heavy fraction during composting, reducing the proportion of total organic carbon from 82.82% to 44.03%, while heavy fraction organic carbon increased to 48.58%. During the first seven days, the reduction rate of light fraction organic carbon decreased slowly, while the increase rate of heavy fraction declined sharply, levelling off thereafter. Light/heavy fraction organic carbon ratio was significantly correlated with existing maturity indicators (carbon/nitrogen ratio, humic acid/fulvic acid ratio, biological growth-related indicators), with the ratio below 1.33 serving as a potential compost maturity marker. Thus, given its simplicity and reliability, organic carbon density fractions is an innovative indicator for compost maturity assessments.

Study on the effect of biomass charcoal-biogas application technology on soil carbon and nitrogen fractions and soil microbiological properties based on biomass charcoal-biogas application technology

Abstract The application of biogas and biomass charcoal to terrestrial crops and vegetables can promote their growth. The effects of the combined application of the two on soil carbon and nitrogen fractions and soil microbiological properties are not well-studied. Therefore, in this experiment, the red and yellow soil of Hangzhou City, Zhejiang Province, was used as the research object, and two factors, biomass charcoal and biogas, were set up to investigate the soil changes under the conditions of biomass charcoal-biogas application. One-way ANOVA and correlation analysis examined the differences in soil and crop radish under biomass charcoal-biogas application technology. The experimental results showed that the 2% application of hog manure charcoal at 350°C and 100% N amount of replacement of biosolids dosing treatments were the most effective, which could increase the content of organic matter, soluble organic carbon, etc., as well as the content of nitrogen in the soil, and improve the activity of soil enzymes. The enhancement of radish yield was greater with the application of swine manure charcoal with biogas than with the single application of both, and the maximum radish yield was achieved with the 100% N amount substitution of biogas with the application of swine manure charcoal at 2%-350°C treatment. The heavy metal contents in radish were below the limit values after 9 months of application of both biogas and biomass charcoal, which did not affect the edible safety of radish.

Effects of Mixed Application of Chemical Fertilizer and Liquid Swine Manure on Dry Matter Yield and Feed Value of Whole Crop Barley

Effects of Mixed Application of Chemical Fertilizer and Liquid Swine Manure on Dry Matter Yield and Feed Value of Whole Crop Barley

Swine manure management by hydrothermal carbonization: Comparative study of batch and continuous operation

Hydrothermal carbonization (HTC) is considered a promising technology for biomass waste management without pre-drying. This study explores the potential for swine manure management by comparing batch and continuous processes, emphasizing the benefits of the continuous mode, particularly for its potential full-scale application. The continuous process at low temperature (180 °C) resulted in a hydrochar with a lower degree of carbonization compared to the batch process, but similar characteristics were found in both hydrochars at higher operating temperatures (230–250 °C), such as C content (∼ 52 wt%), fixed carbon (∼ 24 wt%) and higher calorific value (21 MJ kg−1). Thermogravimetric and combustion analyses showed that hydrochars exhibited characteristics suitable as solid biofuels for industrial use. The process water showed a high content of organic matter as soluble chemical oxygen demand (7–22 g L−1) and total organic carbon (4–10 g L−1), although a high amount of refractory species such as N- and O-containing long aromatic compounds were detected in the process water from the batch process, while the process water from the continuous process presented more easily biodegradable compounds such as acids and alcohols, among others. The longer time required to reach operating temperature in the case of the batch system (longer heating time to reach operating temperature) resulted in lower H/C and O/C ratios compared to hydrochar from the continuous process. This indicates that the dehydration and decarboxylation reactions of the feedstock play a more important role in the batch process. This study shows the efficiency of the continuous process to obtain carbonaceous materials suitable for use as biofuel, providing a solution for swine manure management.

CO2 bubbling pretreatment to remove the inhibition of lime disinfection wastewater in a swine manure anaerobic digestion system

Under the African swine fever epidemic, the extensive use of lime disinfectants has seriously inhibited anaerobic digestion (AD). In this study, the subject was swine manure containing lime disinfectant wastewater. The research set up a carbon dioxide (CO2) bubbling pretreatment device before it entered AD to explore the effect of breaking the inhibition of lime disinfectant. The results showed that the initial pulmonary hypertension (pH) of 11.0 and CO2 bubbling time of 8 h had the best effect, which could reduce calcium ion (Ca2+) by 73.0%, and the biogas production of the batch AD test increased by 28 times. In the continuous AD test, the Ca2+ of CK increased to 7.67 g/L, while the S1 pretreated by CO2 bubbling stabilized at 2.6 g/L, the biogas production in S1 was 112.4% higher than in CK. CO2 bubbling pretreatment reduces the concentration of Ca2+ in swine by utilizing the combination of exogenous CO2 and Ca2+, breaking the inhibitory effect on AD, and thereby improving the performance of the AD system. The test used CO2 in biogas to break the inhibition of lime disinfectants on AD, which was a convenient and feasible pretreatment process.

Feeding strategy determine flexible biogas via shaping microbial abundance and interaction in anaerobic digestion

The optimization of anaerobic digestion systems for enhanced biogas production is reliant on the manipulation of feeding regimes and organic loading. However, the impact of these operations on the microbiota remains unclear. Here, the effects of three distinct feeding regimes (once daily, every 2nd day, and every 3rd day) with two different loading amounts (300 g and 500 g) were investigated in 2 continuously stirred tank reactors treating swine manure. Results indicated that the high organic loading (500 g daily feeding) resulted in increased biogas and methane production, albeit with reduced archaeal alpha diversity. Furthermore, a significant alteration in species distribution was observed with sudden feeding regime changes (300 g every 2nd day) and higher organic loading. Wherein, the core species determined the methane production regarding the different organic loading. The resultant species turnover likely drove the increased biogas production while species loss contributed to the fluctuation of biogas production in intermittent feeding regimes. Despite a decrease in positive connections with high organic loading, the connectivity of Methanosarcinaceae with bacteria increased, thus ensuring higher biogas production. In conclusion, the present study underscores the association between feeding strategies and elevated levels of organic loading with regards to the interdependence between methanogenic microorganisms and keystone bacterial populations. As a consequence, this interplay exerts a discernible influence on the biogas production process.

Solid–Liquid Separation and Its Environmental Impact on Manure Treatment in Scaled Pig Farms—Evidence Based on Life Cycle Assessment

Recently, there has been a significant focus on the issue of pollution caused by livestock and poultry rearing, which is recognized as a prominent contributor to nonpoint source pollution in the agricultural sector. This study employed the life cycle assessment (LCA) methodology to evaluate the environmental impact of several pig manure processing scenarios with the aim of determining the appropriate solid–liquid separation tool for large-scale pig farms. The findings indicate that the utilization of a screw extruder for solid–liquid separation in Scenario 2 has a lower environmental impact. In contrast to Scenario 1, Scenario 2 exhibits reduced environmental potential in the areas of global warming, human toxicity, acidification, and eutrophication. Specifically, the global warming, human toxicity, acidification, and eutrophication impacts decreased by 56%, 81%, 83%, and 273%, respectively, due to the implementation of solid–liquid separation. The type of solid–liquid separation equipment used during the processing of swine manure, as well as the subsequent treatment, have a significant impact on environmental emissions. Compared to Scenario 2, Scenario 3, which utilizes a centrifugal microfilter for solid–liquid separation, exhibits a lower environmental impact in terms of human toxicity, resulting in a reduction of 0.736 kg DCB-eq. In general, solid–liquid separation is a viable and environmentally friendly method for the disposal of waste from large-scale pig farms. The adoption of this method is highly recommended. During its implementation, careful consideration should be given to factors such as separation efficiency and pollution emissions. It is crucial to select appropriate equipment for solid–liquid separation to effectively process the waste.

Assessment of a Novel Real-Time Bio-Liquor Circulation System for Manure Management and Mitigation of Odor Potential in Swine Farming.

Recently, circulating biologically treated manure in slurry pits has been used as an odor reduction technology, but few successful results have been reported, due to the lack of proper control strategies for bioreactors. This study was conducted to investigate the performance of the developed real-time controlled bio-liquor circulation system (BCS) at farm scale. The BCS was operated sequentially as per swine manure inflow (anoxic, aerobic, and settling) circulation to the slurry pit. Each operational phase was self-adjusted in real-time using a novel algorithm for detecting the control point on the oxidation reduction potential (ORP) and pH (mV)-time profiles, the nitrogen break point (NBP), and the nitrate knee point (NKP) in the aerobic and anoxic phases, respectively. The NH4-N in the slurry manure was thoroughly removed (100%) in the bioreactor, optimizing the duration of each operational phase by accurately detecting real-time control points. The newly developed real-time BCS decreased the nitrogen and organic matter in the slurry pit by >70%, and the potential ammonia and methane emissions by 75% and 95%, respectively. This study highlights that improved BCS that utilizes ORP tracking and pH (mV)-time profiles can effectively optimize BCS operation, and thereby reduce malodor and GHG emissions from swine farms.

Phosphorus extractors in soil under no-tillage system with 19 years of swine manure applications

The objective of this study was to evaluate the availability of phosphorus (P) in a soil under no-tillage system after successive applications of liquid swine manure (LSM) doses in soil samples collected at different depths and to select the most appropriate chemical extractors. It was used soil with LSM applications for 19 years, using doses of 0, 25, 50, 75 and 100 m3 ha−1 and mineral fertilization (350 kg ha−1 in formulation 02-20-18), evaluated at the following depths: 0–10, 10–20 and 20–40 cm. The extractors used were Mehlich-1, Mehlich-3, Prem, Olsen, Bray-1 and Resin. Successive fertilizations with LSM, especially with 100 m3 ha−1, increase the availability of P, especially in the 0–10 cm layer, as well adding P in the deeper layers evaluated (20–40 cm). The organic P content in relation to the total P ranged from 16 to 19 %. Bray-1, Olsen and Resin extractors are more efficient in extracting P in soil under no-tillage cultivation after successive fertilizations with liquid swine manure.