Jason G. Warren

The Effect of Alum Addition on Microbial Communities in Poultry Litter

Alum [Al(2)(SO(4))(3).14H(2)O] is a common poultry litter amendment used to decrease water-soluble phosphorus or reduce ammonia volatilization, or both. Although the physiochemical effects of alum addition have been well researched, little attention has been given to the poultry litter microbial communities. The goal of this study was to use molecular biological methods [denaturing gradient gel electrophoresis (DGGE), community cloning, and quantitative real-time PCR] to characterize general, group-specific and pathogenic microbial communities in alum (10% wt/wt) and non-alum-treated litter. According to quantitative real-time PCR analyses, alum addition to the poultry litter resulted in significant reductions in both Campylobacter jejuni and Escherichia coli concentrations by the end of the first month of the experiment (3 log and 2 log, respectively). The concentrations of Salmonella spp. were below detection (<5 x 10(3) cell.g(-1) of litter) for the entire experiment. The DGGE analyses revealed significant reductions in the Clostridium/Eubacterium and low %GC gram-positive groups in the alum-treated litters by the end of the first month, with no bands detectable for either group after 8 wk of incubation. Conversely, minimal effects of alum addition were observed in the Actinomycetes community. The most significant shift in the microbial community (based on DGGE analyses) occurred in the fungal population, with a large increase in diversity and abundance within 1 mo of alum addition (1 dominant band on d 0 to 9 dominant bands at 4 wk). Specifically, the incidence of Aspergillus spp. increased from 0 to 50% of the sequences in fungal clone libraries (n = 80) over the course of the experiment. This suggests that the addition of alum to poultry litter potentially shifts the microbial populations from bacterially dominated to dominated by fungi. The ramifications of this shift in dominance are still unknown, and future work will be aimed at characterizing these fungi and elucidating their role in the acidified litter environment.

Broiler litter application method and runoff timing effects on nutrient and Escherichia coli losses from tall fescue pasture.

The inability to incorporate manure into permanent pasture leads to the concentration of nutrients near the soil surface with the potential to be transported off site by runoff water. In this study, we used rainfall simulations to examine the effect of broiler chicken (Gallus gallus domesticus) litter application method and the runoff timing on nutrient and E. coli losses from tall fescue (Festuca arundinacea Schreb.) pasture on a Hartsells sandy loam soil (fine-loamy, siliceous, subactive, thermic Typic Hapludults)) in Crossville, AL. Treatments included two methods of litter application (surface broadcast and subsurface banding), commercial fertilizer, and control. Litter was applied at a rate of 8.97 Mg ha(-1). Treatments were assigned to 48 plots with four blocks (12 plots each) arranged in a randomized complete block design to include three replications in each block. Simulated rainfall was applied to treatments as follows: Day 1, block 1 (runoff 1); Day 8, block 2 (runoff 2); Day 15, block 3 (runoff 3); and Day 22, block 4 (runoff 4). Total phosphorus (TP), inorganic N, and Escherichia coli concentrations in runoff from broadcast litter application were all significantly greater than from subsurface litter banding. The TP losses from broadcast litter applications averaged 6.8 times greater than those from subsurface litter applications. About 81% of the runoff TP was in the form of dissolved reactive phosphorus (DRP) for both litter-application methods. The average losses of NO(3)-N and total suspended solids (TSS) from subsurface banding plots were 160 g ha(-1) and 22 kg ha(-1) compared to 445 g ha(-1) and 69 kg ha(-1) for the broadcast method, respectively. Increasing the time between litter application and the first runoff event helped decrease nutrient and E. coli losses from surface broadcast litter, but those losses generally remained significantly greater than controls and subsurface banded, regardless of runoff timing. This study shows that subsurface litter banding into perennial grassland can substantially reduce nutrient and pathogen losses in runoff compared to the traditional surface-broadcast practice.

Phosphorus removal with by-products in a flow-through setting.

Phosphorus (P) losses to surface waters can result in eutrophication. Some industrial by-products have a strong affinity for dissolved P and may be useful in reducing nonpoint P pollution with landscape-scale runoff filters. Although appreciable research has been conducted on characterizing P sorption by industrial by-products via batch isotherms, less data are available on P sorption by these materials in a flow-through context integral to a landscape P filter. The objectives of this study were to evaluate several industrial by-products for P sorption in a flow-through setting, to determine material chemical properties that have the greatest impact on P sorption in a flow-through setting, and to explore how retention time (RT) and P concentration affect P removal. Twelve materials were characterized for chemical properties that typically influence P removal and subjected to flow-through P sorption experiments in which five different RTs and P concentrations were tested. The impact of RT and P concentrations on P removal varied based on material chemical properties, mainly as a function of oxalate-extractable aluminum (Al), iron (Fe), and water-soluble (WS) calcium (Ca). Statistical analysis showed that materials elevated in oxalate-extractable Al and Fe and WS Ca and that were highly buffered above pH 6 were able to remove the most P under flow-through conditions. Langmuir sorption maximum values from batch isotherms were poorly correlated with and overestimated P removal found under flow-through conditions. Within the conditions tested in this study, increases in RT and inflow P concentrations increased P removal among materials most likely to remove P via precipitation, whereas RT had little effect on materials likely to remove P via ligand exchange.

Determination of ammonia and greenhouse gas emissions from land application of swine slurry: A comparison of three application methods

In this study, the comparison and monitoring of the initial greenhouse gas (GHG) emissions using a flux chamber and gas analyzer from three different liquid manure application methods at a swine farm in Kentucky were carried out. Swine slurry was applied to farmland by row injection, surface spray, and Aerway injection. Ammonia and GHG concentrations were monitored immediately after application, 72 and 216h after application. The results showed that the initial ammonia flux ranged from 5.80 mg m(-2)h(-1) for the surface spray method to 1.80 mg m(-2)h(-1) for the row injection method. The initial fluxes of methane ranged from 8.75 mg m(-2)h(-1) for surface spray to 2.27 mg m(-2)h(-1) for Aerway injection, carbon dioxide ranged from 4357 mg m(-2)h(-1) for surface spray to 60 mg m(-2)h(-1) for row injection, and nitrous oxide ranged from 0.89 mg m(-2)h(-1) for surface spray to 0.22 mg m(-2)h(-1) for row injection. However, the Aerway injection method seemed to create the highest gas (GHG) concentrations inside the monitoring chambers at the initial application and produced the highest gas fluxes at subsequent sampling time (e.g., 72h after application). Nevertheless, the surface spray method appeared to produce the highest gas fluxes, and the row injection method appeared to emit the least amount of greenhouse gases into the atmosphere. Gas fluxes decreased over time and did not depend on the initial headspace concentration in the monitoring flux chambers.

The Impact of Alum Addition on Organic P Transformations in Poultry Litter and Litter-Amended Soil

Poultry litter treatment with alum (Al(2)(SO(4))(3) . 18H(2)O) lowers litter phosphorus (P) solubility and therefore can lower litter P release to runoff after land application. Lower P solubility in litter is generally attributed to aluminum-phosphate complex formation. However, recent studies suggest that alum additions to poultry litter may influence organic P mineralization. Therefore, alum-treated and untreated litters were incubated for 93 d to assess organic P transformations during simulated storage. A 62-d soil incubation was also conducted to determine the fate of incorporated litter organic P, which included alum-treated litter, untreated litter, KH(2)PO(4) applied at 60 mg P kg(-1) of soil, and an unamended control. Liquid-state (31)P nuclear magnetic resonance indicated that phytic acid was the only organic P compound present, accounting for 50 and 45% of the total P in untreated and alum-treated litters, respectively, before incubation and declined to 9 and 37% after 93 d of storage-simulating incubation. Sequential fractionation of litters showed that alum addition to litter transformed 30% of the organic P from the 1.0 mol L(-1) HCl to the 0.1 mol L(-1) NaOH extractable fraction and that both organic P fractions were more persistent in alum-treated litter compared with untreated litter. The soil incubation revealed that 0.1 mol L(-1) NaOH-extractable organic P was more recalcitrant after mixing than was the 1.0 mol L(-1) HCl-extractable organic P. Thus, adding alum to litter inhibits organic P mineralization during storage and promotes the formation of alkaline extractable organic P that sustains lower P solubility in the soil environment.

Effect of alum treatment on the concentration of total and ureolytic microorganisms in poultry litter.

Microbial mineralization of urea and uric acid in poultry litter results in the production of ammonia, which can lead to decreased poultry performance, malodorous emissions, and loss of poultry litter value as a fertilizer. Despite the fact that this is a microbial process, little is known about how the microbial populations, especially ammonia-producing (ureolytic) organisms in poultry litter, respond to litter amendments such as aluminum sulfate (Al(2)(SO(4))(3).14H(2)O; alum). The goal of this study was to measure the temporal changes in total bacterial and fungal populations and urease-producing microorganisms in nontreated litter or litter treated with 10% alum. Quantitative real-time polymerase chain reaction was used to target the bacterial 16S rRNA gene, the fungal 18S rRNA gene, or the urease gene of bacterial and fungal ammonia producers in a poultry litter incubation study. Nontreated poultry litter had relatively high total (2.8 +/- 0.8 x 10(10) cells g(-1) litter) and ureolytic (2.8 +/- 1.3 x 10(8) cells g(-1) litter) bacterial populations. Alum treatment reduced the total bacterial population by 50% and bacterial urease producers by 90% within 4 wk. In contrast, at 16 wk after alum treatment, the fungal population was three orders of magnitude higher in alum-treated litter than in nontreated litter (3.5 +/- 0.8 x 10(7) cells g(-1) litter and 5.5 +/- 2.5 x 10(4) cells g(-1) litter, respectively). The decrease in pH produced by alum treatment is believed to inhibit bacterial populations and favor growth of fungi that may be responsible for the mineralization of organic nitrogen in alum-treated litters.

Development of a Quantitative Real-Time Polymerase Chain Reaction Assay to Target a Novel Group of Ammonia-Producing Bacteria Found in Poultry Litter

Ammonia production in poultry houses has serious implications for flock health and performance, nutrient value of poultry litter, and energy costs for running poultry operations. In poultry litter, the conversion of organic N (uric acid and urea) to NH(4)-N is a microbially mediated process. The urease enzyme is responsible for the final step in the conversion of urea to NH(4)-N. Cloning and analysis of 168 urease sequences from extracted genomic DNA from poultry litter samples revealed the presence of a novel, dominant group of ureolytic microbes (representing 90% of the urease clone library). Specific primers and a probe were designed to target this novel poultry litter urease producer (PLUP) group, and a new quantitative real-time PCR assay was developed. The assay allowed for the detection of 10(2) copies of target urease sequences per PCR reaction (approximately 1 x 10(4) cells per gram of poultry litter), and the reaction was linear over 8 orders of magnitude. Our PLUP group was present only in poultry litter and was not present in environmental samples from diverse agricultural settings. This novel PLUP group represented between 0.1 to 3.1% of the total microbial populations (6.0 x 10(6) to 2.4 x 10(8) PLUP cells per gram of litter) from diverse poultry litter types. The PLUP cell concentrations were directly correlated to the total cell concentrations in the poultry litter and were found to be influenced by the physical parameters of the litters (bedding material, moisture content, pH), as well as the NH(4)-N content of the litters, based on principal component analysis. Chemical parameters (organic N, total N, total C) were not found to be influential in the concentrations of our PLUP group in the diverse poultry litters Future applications of this assay could include determining the efficacy of current NH(4)-N-reducing litter amendments or in designing more efficient treatment protocols.

Nutrient source and tillage impact on corn grain yield and soil properties.

Large amounts of animal manure, particularly poultry litter and dairy manure, are generated in southeastern United States, where corn (Zea mays L.) is also extensively grown. Characterizations of management practices and long-term manure and soil nutrient dynamics are critical. This study examined corn grain yield and soil nutrient status under three nutrient sources (two rates of each) as follows: inorganic fertilizer, poultry litter, and dairy manure compared with a nontreated control under two tillage practices (no-till and incorporated). Treatments were replicated four times in a split-plot design from 2004 to 2007. Soil samples were taken annually in the spring before treatment application to evaluate the status of the residual nutrients in soil. Significant differences in corn grain yield between the two tillage practices (main effect) were observed in all 4 years. The high rate of poultry litter application produced similar grain yield as inorganic fertilizer. However, results from dairy manure were not as consistent as poultry litter. After 4 years of poultry litter application, Mehlich-3 (M-3) phosphorus (P) increased from an initial 31.4 to 63.0 mg kg−1 for the 4.5 Mg ha−1 year−1 rate and to 178 mg kg−1 for the 13.5 Mg ha−1 year−1 rate. More specifically, 5.2 kg ha−1 year−1 of P applied as poultry litter increased soil M-3 P by 1 mg kg−1 after 4 years of application. Results indicated that poultry litter is a primary fertilizer at the rate of 13.5 Mg ha−1 applied in four consecutive years on a silt loam soil-produced corn grain yields similar to inorganic fertilizer under both no-till and incorporated systems and did not result in residual soil test P, Cu, and zinc levels considered to be harmful to surface water or cropping systems.

Electrical Conductivity and Sodium Adsorption Ratio Changes Following Annual Applications of Animal Manure Amendments

Field experiments were conducted to evaluate the effects of repeated annual manure applications on sodium adsorption ratios and electrical conductivity in semi-arid environments. Swine effluent, beef manure, and anhydrous ammonia were annually applied at loading rates of 0, 56, 168, and 504 kg nitrogen (N) ha−1 to an irrigated, conventionally tilled, continuous corn (Zea mays L.) cropping study in the Oklahoma panhandle. Sodium adsorption ratios increased with swine effluent additions at the high N loading rate application; however, sodium adsorption ratio decreased with the high anhydrous ammonia loading applications and remained unchanged with beef manure applications. Linear correlations were found for swine effluent and anhydrous ammonia applications when N levels increased. Electrical conductivity levels increased 2.35 dS m−1 with the high anhydrous ammonia loading rate to a level where relative yields for crop production may be at risk of being reduced 50%.

Nitrogen source and application method impact on corn yield and nutrient uptake

ABSTRACT Farmers are looking for better management practices to utilize animal manure as an alternative to chemical fertilizers. A 2-year field experiment was conducted to study the effects of nitrogen (N) fertilizer source and application methods to Nicholson silt loam soil in central Kentucky, USA for no-till corn (Zea mays) production. The region has a temperate climate with a mean temperature of 14.5°C and rainfall of 1300 mm year−1. Treatments included a control, 179 kg N ha−1 urea ammonium nitrate (UAN) applied as preplant and sidedress, and swine effluent that was applied by three methods: broadcast, injection, and Aerway. Injection method produced the greatest corn grain yield (11.88 Mg ha−1) and biomass yield (18.9 Mg ha−1) in 2007. Results demonstrated that the effluent application methods and the timing of UAN application may not be agronomically important for corn production in this region. Hence, more studies are needed on different soils in this region.