Fresh Poultry Litter Research Articles

Role of Organic Fertilizer in the Transfer of Lead to Vegetables Produced in Tropical Mountain Agroecosystems.

Understanding the relationship between the aerobic transformation of organic matter (OM) and the bioavailability of lead to plants may allow the safe application of organic fertilizers (OF) in agriculture. The present study aimed to elucidate the relationship of different OM structures with Pb, revealing the action of OF (poultry litter) on Pb dynamics, presenting the effects of OM transformations on bioavailability and transfer to vegetables produced in tropical mountain agroecosystems (TMA). The association of Pb with hydrophilic structures (CAlk-O and CAlk-di-O) during the aerobic transformation of poultry litter (PL) contributes to the increase in the water-soluble form of this metal (3.17-15.30%). The structural changes promoted by the transformation of OM, in addition to reducing the adsorption capacity of Pb in PL (Kd reduction from 1135.50 to 87.49), favor the formation of outer-sphere complexes. PL that have a more labile structure, i.e., those that are less humified, have greater affinity for Pb. The greater affinity of Pb for labile structures that are preserved in PL during OM transformations contributed to its increase and transport to edible plant parts. Considering the edible parts of vegetables grown in TMA and fertilized with fresh PL, 100% of broccoli, 91.78% of cabbage, 80.00% of tomato, 65.96% of parsley, 49.19% of lettuce, and 32.88% of cauliflower showed Pb contamination that exceeded the permitted level. Therefore, OF contributes to lead contamination of food produced in TMA, representing a risk to human health. Studies are needed to propose additional treatments for this residue before its use.

Investigation of antimicrobial resistance genes in organic fertilizers from animal residues

Animal wastes have been commonly reused in agriculture due to improve organic matter and nutritional input. However, organic animal fertilizers can be sources of antimicrobials, bacteria resistant to antimicrobials, and antimicrobial resistance genes. In this perspective, this work aimed to investigate the pr essence of antimicrobial resistance genes in organic animal wastes, such as fresh bovine manure from organic and conventional production systems, fresh and tanned organic poultry litter, conventional poultry litter tanned and bone meal. Sulfonamide resistance genes were detected in all residues. On the other hand, colistin and carbapenem resistance genes were not detected in any samples. A tetracycline resistance gene was detected in poultry litter. Quinolone resistance genes were detected in all samples, except bone meal. Despite the advantage of applying animal wastes in agricultural production, the existence of resistance genes in all residues, regardless of whether they come from organic or conventional systems, fresh or tanned, represents a public health risk since we can increase antimicrobial resistance genes in the soil which can favor the transfer to pathogenic bacteria of humans and animals.

Toxic Metals in Broccoli by Combined Use of Acidity Correctives and Poultry Litter Under Mountain Tropical Conditions.

The current study was developed to evaluate agronomic efficiency and food security of isolated or simultaneous use of two residues-steel slag and fresh or composted poultry litter-in the cultivation of broccoli (Brassica oleracea var. italica). The composition and contribution of toxic and potentially toxic metals by different treatments and contents, translocation, and accumulation of Pb, Cd, Cu, Fe, Mn, and Zn in different plant organs were analyzed. Then, risks to human health associated with consumption of inflorescences were based on the indices of estimated daily intake, noncarcinogenic target hazard quotient, total hazard index (THI), and carcinogenic risk factor (CR), considering adults and children. Steel slag was similar to limestone in terms of the corrective effect of acidity and, despite containing toxic metals, it did not contribute to their higher translocation to inflorescences. Composting favored the concentrations of Pb, Cu, and Zn in poultry litter. The combined use of steel slag and fresh poultry litter and, mainly, composted poultry litter, favored absorption and translocation of Pb for inflorescences, that is, 60.37% and 66.13% of all Pb absorbed, respectively. Consumption of inflorescences from these treatments resulted in the critical THI values of 1.03 and 1.52, respectively, with Pb and Cd being the metals that mostly contributed to the risk. The registered CR was higher than the threshold level of 10-6. The use of steel slag associated with poultry litter favors contamination of broccoli inflorescences and increases risks to human health due to their consumption.

Maize yields and carbon pools in response to poultry litter, rock phosphate and P-solubilizing microorganisms

ABSTRACT: The acid release of phosphates from rock phosphates (RP) and the retention of ammonium by inorganic phosphates have been studied separately in composting; however, there is a gap in the knowledge of combined application of RP with organic residues and microorganisms. The objectives were to evaluate the combined application of fresh poultry litter (PL) with RP and P-solubilizing microorganisms (M) on soil organic matter pools, microbial biomass C (MB-C) and on whole-plant silage maize and grain yields. Two field experiments tested the effects of timing of applications of PL (8 Mg ha–1), RP (4 Mg ha–1) and microorganisms on soil organic matter pools, nutritional aspects and productive components of maize crop whole-plant silage. A second experiment evaluated the effects of RP doses (0, 3, 6 and 9 Mg ha–1) with a fixed dose of PL (8 Mg ha–1) on maize grains. Application of PL+RP decreased soil organic C, while RP alone increased the humin fraction C compared to the control. The MB-C in soil with PL and PL+RP+M increased in comparison to the control and the RP. The application of PL, based on an average of fall and spring, increased leaves + stem dry matter, while in the fall on its own, the highest cob yield was observed in the combination of PL+RP, showing synergistic effects. The best ratio of poultry litter to rock phosphate combination is 2:1 in the anticipated fall application on the maize silage crop or immediate application on the maize grain crops.

Biochar production from poultry litter as management approach and effects on plant growth

PurposeA lots of poultry litter (PL) is being generated every day from poultry industries and improper management leads to different environmental problems. Production of biochar from PL is a new management strategy of PL which is a nutrient-rich organic amendment for improving soil nutritional status. The experiment was aimed for the production of poultry litter biochar (PLB) from fresh PL to assess the important properties of both PL and PLB, and to observe the effects on plant growth. It also appraised the change of soil properties after PL and PLB application.MethodsPoultry litter biochar was produced from fresh PL heated at 300 °C temperature for 10 min in muffle furnace. Poultry litter was applied into the soil at 2.5, 5.0, 7.5 and 10 t ha−1 and PLB was applied at 1, 2, 3 and 4 t ha−1 along with control. Gima kalmi (Ipomoea aquatica) was grown as test plant. To assess the potentiality and residual effect, the same plant was grown consecutively after harvesting first crop. Post-harvest soil analysis was also carried out after harvesting the first crop.ResultsAfter pyrolysis pH, EC, organic carbon, available nitrogen, phosphorus, potassium, calcium, total phosphorus, potassium, calcium, magnesium, and iron were increased in PLB. A significant (p < 0.001) increase in plant growth and biomass production was observed and it was higher in PLB-treated soil than that of the PL-treated soil for both first and second crop.ConclusionPoultry litter biochar might be a promising organic fertilizer with high nutrient composition than fresh PL. This also could be an ecofriendly management strategy for sustainable agriculture and long-term productivity.

Agricultural Practices Influence Salmonella Contamination and Survival in Pre-harvest Tomato Production.

Between 2000 and 2010 the Eastern Shore of Virginia was implicated in four Salmonella outbreaks associated with tomato. Therefore, a multi-year study (2012–2015) was performed to investigate presumptive factors associated with the contamination of Salmonella within tomato fields at Virginia Tech’s Eastern Shore Agricultural Research and Extension Center. Factors including irrigation water sources (pond and well), type of soil amendment: fresh poultry litter (PL), PL ash, and a conventional fertilizer (triple superphosphate – TSP), and production practices: staked with plastic mulch (SP), staked without plastic mulch (SW), and non-staked without plastic mulch (NW), were evaluated by split-plot or complete-block design. All field experiments relied on naturally occurring Salmonella contamination, except one follow up experiment (worst-case scenario) which examined the potential for contamination in tomato fruits when Salmonella was applied through drip irrigation. Samples were collected from pond and well water; PL, PL ash, and TSP; and the rhizosphere, leaves, and fruits of tomato plants. Salmonella was quantified using a most probable number method and contamination ratios were calculated for each treatment. Salmonella serovar was determined by molecular serotyping. Salmonella populations varied significantly by year; however, similar trends were evident each year. Findings showed use of untreated pond water and raw PL amendment increased the likelihood of Salmonella detection in tomato plots. Salmonella Newport and Typhimurium were the most frequently detected serovars in pond water and PL amendment samples, respectively. Interestingly, while these factors increased the likelihood of Salmonella detection in tomato plots (rhizosphere and leaves), all tomato fruits sampled (n = 4800) from these plots were Salmonella negative. Contamination of tomato fruits was extremely low (< 1%) even when tomato plots were artificially inoculated with an attenuated Salmonella Newport strain (104 CFU/mL). Furthermore, Salmonella was not detected in tomato plots irrigated using well water and amended with PL ash or TSP. Production practices also influenced the likelihood of Salmonella detection in tomato plots. Salmonella detection was higher in tomato leaf samples for NW plots, compared to SP and SW plots. This study provides evidence that attention to agricultural inputs and production practices may help reduce the likelihood of Salmonella contamination in tomato fields.

Patterns of antibiotic resistance in Escherichia coli isolated from fresh and recycled poultry litter

Patterns of antibiotic resistance in Escherichia coli isolated from fresh and recycled poultry litter

Copper and Zinc Runoff from Land Application of Composted Poultry Litter.

Regions with long-term animal manure applications based on nitrogen (N) requirements have concerns regarding elevated nutrient levels. Most attention has focused on phosphorus (P), but heavy metal accumulation has received attention due to perceived environmental concerns. Composting is a potential management practice that can reduce total manure mass and volume while creating a stabilized product that has less odor and fewer pathogens. However, composting animal manures can lead to high N loss via ammonia volatilization and increased concentrations of nonvolatile nutrients. The objective of this study was to measure copper (Cu) and zinc (Zn) concentrations in runoff water from plots fertilized with composted and fresh poultry litter. Seven treatments were evaluated in the first year: (i) unfertilized control, (ii) fresh poultry litter, (iii) normal compost (no amendment), (iv) composted litter with alum, (v) composted litter with phosphoric acid, (vi) composted litter with a microbial mixture, and (vii) composted litter with alum + microbial mixture. Six of these treatments were evaluated in Year 2 (alum + microbial mixture was not evaluated in Year 2). Rainfall simulators were used to produce a 5 cm h storm event sufficient in length to cause 30 min of continuous runoff. Concentrations of Cu and Zn were elevated in compost compared with fresh poultry litter. However, metal concentrations in compost did not correlate well with metal concentrations in runoff water and may have been affected by compost maturity and amendment. Total Cu and Zn concentrations in runoff water did not differ between alum-amended compost and fresh poultry litter in each year.

Solanum lycopersicum (tomato) hosts robust phyllosphere and rhizosphere bacterial communities when grown in soil amended with various organic and synthetic fertilizers

Due to the intimate association between plants and their microbial symbionts, an examination of the influence of agricultural practices on phytobiome structure and diversity could foster a more comprehensive understanding of plant health and produce safety. Indeed, the impact of upstream crop producti006Fn practices cannot be overstated in their role in assuring an abundant and safe food supply. To assess whether fertilizer type impacted rhizosphere and phyllosphere bacterial communities associating with tomato plants, the bacterial microbiome of tomato cv. ‘BHN602’ grown in soils amended with fresh poultry litter, commercially available sterilized poultry litter pellets, vermicompost or synthetic fertilizer was described. Culture independent DNA was extracted from bulk and rhizosphere soils, and washes of tomato blossoms and ripe fruit. PCR amplicons of hypervariable regions of the 16S rRNA gene were sequenced and profiled using the QIIME pipeline. Bulk and rhizosphere soil, and blossom and fruit surfaces all supported distinct bacterial communities according to principal coordinate analysis and ANOSIM (R=0.87, p=0.001 in year 1; R=0.93, p=0.001 in year 2). Use of microbiologically diverse organic fertilizers generally did not influence bacterial diversity, community structure or relative abundance of specific taxa on any plant organ surface. However, statistically significant differences in sand and silt contents of soil (p<0.05) across the field and corresponding shifts in water activity were positively (R2=0.52, p=0.005) and negatively (R2=0.48, p=0.009) correlated with changes in bacterial community structure in the rhizosphere, respectively. Over two harvest seasons, this study demonstrated that the application of raw poultry manure, poultry litter pellets and vermicompost had little effect on the tomato microbiome in the rhizosphere and phyllosphere, when compared to synthetically fertilized plants. Plant anatomy, and other factors related to field location, possibly associated with edaphic and air characteristics, were more influential drivers of different tomato organ microbiomes than were diverse soil amendment applications.

The effect of composting on the persistence of four ionophores in dairy manure and poultry litter

Manure composting is a well-described approach for stabilization of nutrients and reduction of pathogens and odors. Although composting studies have shown that thermophilic temperatures and aerobic conditions can increase removal rates of selected antibiotics, comparable information is lacking for many other compounds in untreated or composted manure. The objective of this study was to determine the relative effectiveness of composting conditions to reduce concentrations of four widely used ionophore feed supplements in dairy manure and poultry litter. Replicate aliquots of fresh poultry litter and dairy manure were amended with monensin, lasalocid, salinomycin, or amprolium to 10mgkg−1DW. Non-amended and amended dairy manure and poultry litter aliquots were incubated at 22, 45, 55, or 65°C under moist, aerobic conditions. Residue concentrations were determined from aliquots removed after 1, 2, 4, 6, 8, and 12weeks. Results suggest that the effectiveness of composting for contaminant reduction is compound and matrix specific. Composting temperatures were not any more effective than ambient temperature in increasing the rate or extent of monensin removal in either poultry litter or dairy manure. Composting was effective for lasalocid removal in poultry litter, but is likely to be too slow to be useful in practice (8–12weeks at 65°C for >90% residue removal). Composting was effective for amprolium removal from poultry litter and salinomycin in dairy manure but both required 4–6weeks for >90% removal. However, composting did not increase the removal rates or salinomycin in poultry litter or the removal rates of lasalocid or amprolium in dairy manure.

Nutrient cycling in an agroforestry alley cropping system receiving poultry litter or nitrogen fertilizer

Optimal utilization of animal manures as a plant nutrient source should also prevent adverse impacts on water quality. The objective of this study was to evaluate long-term poultry litter and N fertilizer application on nutrient cycling following establishment of an alley cropping system with eastern black walnut (Juglans nigra L.), pecan [Carya illinoensis (Wangenh.) K. Koch], and northern red oak (Quercus rubra L.) trees and orchardgrass (Dactylis glomerata L.). One half of a 4.25-ha site in northwestern Arkansas USA received broadcast applications of 3.9–6.7 Mg ha−1 fresh poultry litter and the other half 50–76 kg ha−1 N as NH4NO3 fertilizer each spring from 2001 to 2008. Macronutrient (N, P, K, Ca, Mg, and S) and micronutrient (Na, Fe, Mn, Zn, and Cu) concentrations in soil, forage, and tree leaf tissue were monitored along with NO3-N in soil water and groundwater. Poultry litter application resulted in significantly increased concentrations of each macronutrient except S with increases from 6.3 (N) to 121 % (P). Nitrogen fertilizer application resulted in decreased concentrations from 2.1 (N) to 60.9 % (S) for all macronutrients except Ca. Patterns of nutrient content in forage and tree leaf tissue did not generally follow patterns of soil nutrient concentrations suggesting nutrient sufficiency in most years and that climate and plant growth had a greater effect on nutrient uptake. Soil P with litter application increased 41.3 mg kg−1 over 7 years (from 34.1 to 75.4), which may necessitate a lower litter application rate to avoid excessive P runoff.

Centrifugal spreader mass and nutrients distribution patterns for application of fresh and aged poultry litter

A spin-type centrifugal spreader was evaluated using fresh and aged poultry litter upon dry mass, product nitrogen (N), phosphorus (P) and potassium (K), incubation study soil available N and particle size distribution patterns. Relative to the aged litter (37% moisture content), the fresh litter (17% moisture content) had greater <1.00 mm particle size fraction weights and atmospheric particulate was launched, which posed as a potential fallout to adjacent fields, waterways and residences. Relative to the aged litter, the broadcast fresh litter resulted in higher coefficients of variation (CV) over its transverse distance, a narrower calculated space distance between passes for uniform spread and lower soil available N concentrations. For nitrogen application over the broadcast transverse distance the fresh litter displayed a high R2 best fit 4th order polynomial distribution pattern, while the aged litter showed high R2 best fit 6th order polynomial distribution pattern. A soil incubation study of the fresh and aged broadcast litter resulted in a more variable or lower R2 best fit 2nd order polynomial distribution pattern. For both the fresh and aged litter, the calculated distance between passes to achieve a uniform mass distribution was greater than that required for the broadcast of soil available N. For the fresh litter, the soil available N and litter P concentration levels strongly correlated (relatively high p and R2 values) with the <1.00 mm fraction weight, while for the aged litter this relationship was not as significant. In addition to reducing the health risk (i.e. pathogens, antibiotic residues and resistant bacteria) and/or environment issues (particulate fallout onto waterways, adjacent fields and/or residences) our study mass, particulate and N distribution patterns results suggest that poultry litter should be allowed to age before broadcast application is attempted.

Binding Agents Effect on Physical and Chemical Attributes of Nitrogen-Fortified Poultry Litter and Biosolids Granules

<abstract><title><italic>Abstract. </italic></title> Northwest Arkansas (NWA) is a region of high-density confined animal feeding operations (CAFOs) that produces annual surpluses of poultry litter (PL) and municipal biosolids (BS) that can be used in organic fertilizer formulations. The objective of this study was to evaluate the effect of various binding agents and a nitrification inhibitor [dicyandiamide (DCD)] on granule physical strength and nutrient water solubility. We produced four different granule formulations using agglomeration techniques with a pin mixer in a 2 × 2 × 3 factorial arrangement. Treatments included PL granules with and without BS, with and without DCD, and bound with lignosulfonate, urea formaldehyde, or water. These 12 granular products were tested for bulk density, physical strength, and water-soluble N and P. Overall, granulated products were bulkier (0.48 to 0.64 g cm^-3) than commercial urea fertilizer and BS (0.81 and 0.76 g cm^-3, respectively) but had a higher bulk density than fresh PL (0.40 g cm^-3). Compared to urea and triple superphosphate (TSP) fertilizers, granules were more resistant to crumbling during force crush tests but degraded faster during attrition tests. Generally, the heat-dependent granulation process increased granule DRP concentrations by up to 278% compared to unprocessed ingredients. Based on ingredient and production costs, granules can be produced for $0.82 to $1.24 kg^-1 N, similar to commercially available urea ($0.99 kg^-1 N). Organic, granular fertilizers also contain other macro- and micronutrients that adds additional value to the formulations not accounted for in this study. Using the granulation process, significant amounts of PL and BS could economically be transported out of sensitive nutrient surplus watersheds in NWA to areas suffering from nutrient deficiencies.

Effects of fresh and digested cowdung and poultry litter on the growth and yield of cabbage (Brassica oleracea)

A field experiment was conducted during Rabi season in the experimental field of BCSIR to see the effects of fresh and digested cowdung (CD) and poultry litter (PL) bio-slurry on the growth and yield of cabbage (Brassica oleracea). The experiment was laid in a Randomized Complete Block Design (CRBD) with six different treatments including control. Cabbage variety Atlas-70 was transplanted at the age of 35 days and was harvested at 120 days. Plant height, circumference, marketable weights and whole plant weight were examined to perceive the effects on the growth and yield of cabbages. The experiment revealed that both digested PL and CD bio-slurry had a significant effect (P &lt; 0.01) on the growth and yield components of cabbage. Increased plant growth and yield were in the order of digested PL bio-slurry &gt; digested CD bio-slurry &gt; fresh PL &gt; fresh CD in combination with recommended dose of fertilizers (RDF). Among the treatments, the highest head yield of cabbage (97.6 t ha-1) was obtained from RDF + 5 t ha-1 digested PL bio-slurry which was 366 % higher than the control. DOI: http://dx.doi.org/10.3329/bjsir.v48i1.15382 Bangladesh J. Sci. Ind. Res. 48(1), 1-6, 2013

Efficacy of Some Commercial Chemical Disinfectants on Salmonella enterica Serovar Typhimurium

Problem statement: Poultry industry is intensive and consistently applies an all-in, all-out system with the aim of minimizing infection pressure and targeting specific pathogens like Salmonella which remains one of the leading causes of food-borne illness, many questions regarding the introduction and persistence in animal production still remain. Therefore disinfection during production break is a routine part of the biosecurity programs of poultry houses. The correct usage of disinfectants is an important key of a successful biosecurity program in poultry farms and in-turn the role of the scientist was to evaluate the efficacy of these disinfection programs. Approach: In this study five commercial disinfectants [Green work (green non anionic surfactant), Sanidate RTU (hydrogen peroxide compound), Hi-yeild®consan 20® (phenolic compound), Tektrol® (quaternary ammonium compound) and Kreso®D (phenolic compound)] were evaluated against Salmonella typhimurium in two different experimental conditions. In Experiment I, S. typhimurium was inoculated into fresh poultry litter (aluminum trays L: 30 cm × W: 25 cm × D: 6 cm filled with wood shavings) by inoculums size of ~107 CFU mL-1 and then mixed with 100 g of fresh poultry droppings. Sample sizes of 3 g were obtained daily for the bacterial counts. Green work achieved100% killing of S. typhimurium by day 7 (p≤0.0001); Sanidate RTU achieved100% killing by day 6 (p≤0.001); Hi-yield® Consan®, Tektrol® and Kreso® D achieved100% killing by day 5 (p≤0.001). Disinfectants were also compared to each other in their efficacy each day. At day 1, Green work was inferior to all other disinfectants at (p≤0.05). On day 2, Kreso® D was significantly superior to Tektrol®, Hi-yield® Consan®, Sanidate RTU and Green work at p≤0.01, p≤0.01, p≤0.01, p≤0.005; respectively. At day 4 Kreso® D was significantly superior to Hiyield ® Consan® at p≤0.01, Tektrol® was also significantly superior to Green work at p≤0.01. In experiment II; MIC use-dilution test was used to evaluate the five disinfectants against S. typhimurium (~107CFU mL-1) in the absence of organic matter. Results: Hourly samples were collected for the bacterial counts. Maximum efficacy (100% killing efficacy against S. typhimurium) was achieved for Green Work after 16 h (p≤0.0001), with Sanidate RTU after 8 h (p≤0.0001), with Hi-yield® Consan® and Kreso® D after 2 h at (p≤0.0001) and with Tektrol® after 4 h (p≤0.0001). In presence of organic matter Green work and Sanidate RTUachieved 100% killing efficacy against S. typhimurium after 16 h (p≤0.0001), Hi-yield® Consan® and Kreso® D after 2 h at (p≤0.0001); Tektrol® after 8 h (p≤0.0001). When disinfectants were compared to each other in relation to time; we found that there was no kind of significance between their efficacies. When compared to other tested disinfectants, Kreso® D which is a phenolic compound revealed superior activity against Salmonella typhimurium in the two experiments. Conclusion: The study showed that many disinfectants regardless to their constituents continues to give a very powerful efficacy against the most virulent bacterial strains, but the question remain can they be used in the presence of live birds. Further studies are required to explore the safety and the efficacy of these compounds when applied in poultry farms in the presence of live birds.

Effect of Five‐Year Continuous Poultry Litter Use in Cotton Production on Major Soil Nutrients

Repeated application of poultry (Gallus gallus) litter to crop lands may lead to nitrates leaching and build up of P and other elements in the soil profile, which are prone to loss from runoff and erosion. A study was conducted for 5 yr at Belle Mina, AL on a Decatur silt loam (fine, kaolinitic thermic Rhodic Paleudult) during 1994 to 1998 to determine the nitrate movement and quantify the build up of P, K, Ca, and Mg due to the application of nitrification inhibitor, carboxymethyl pyrazole (CP), treated fresh and composted poultry litter and urea in conventionally tilled cotton (Gossypium hirsutum L.). Poultry litter maintained soil pH (0–30 cm depth) where as application of urea resulted in a pH decline. The inhibitor, CP, significantly reduced the NO3−–N formation in all N sources for 41 d following application. However, over the longer period of time, very minimal changes in nitrate concentrations were observed due to change in rates or sources of N. Over the experimental period, P concentration increased significantly (by 74%) in composted litter applied plots (17.7 mg kg−1) but not in fresh litter plots (1.5 mg kg−1). Linear increase in P accumulation was observed with increase in rate of composted litter. Concentrations of K and Mg increased significantly both in fresh (93 and 25 mg kg−1, respectively) and composted litter (127 and 36 mg kg−1, respectively) applied plots by the end of 5 yr period. These results indicate that a well‐planned application of fresh poultry litter in soils that are not already overloaded with P is safe and treating litter with CP is advantageous from an environmental perspective.

Organic Fertility Sources for the Production of Short-day Organic Onion Transplants

This study evaluated poultry litter, commercial organic fertilizer, and compost for organic production of onion (Allium cepa) transplants within the Vidalia onion growing region of southeastern Georgia. Two field experiments were conducted. The first experiment tested six rates of poultry litter (0–10 tons/acre). The second experiment tested a factorial combination of two rates of nitrogen (N) (0 and 130 lb/acre) and three rates of compost (0, 5, and 10 tons/acre). Seedling weight, length, and diameter were measured ≈10 weeks after sowing. Poultry litter had a significant increasing linear effect on plant weight and diameter. There was also a significant increasing quadratic effect on plant length. Commercial organic fertilizer (3N–0.9P–2.5K) at 130 lb/acre N had a significant effect on plant length, but compost at 0, 5, or 10 tons/acre did not affect plant length. There were organic fertilizer by compost interactions for plant weight and diameter. There was a significant effect on plant diameter with organic fertilizer (130 lb/acre N) and 10 tons/acre compost, but there was no fertilizer effect on plant diameter at 0 or 5 tons/acre compost. The interaction effect on plant weight indicated there was a significant effect from fertilizer with 5 and 10 tons/acre compost, but not with 0 tons/acre. Based on this study, nutrition should not be a problem in producing organic onion transplants in southeastern Georgia. Four to 6 tons/acre fresh poultry litter should be adequate for producing good quality transplants. An alternative approach of using organic fertilizer at a rate of 130 lb/acre N with 5 to 10 tons/acre compost can also be used to produce good quality transplants.

Effect of Chemical and Microbial Amendment on Phosphorus Runoff from Composted Poultry Litter

Environmental impacts of composting poultry litter with chemical amendments at the field scale have not been well quantified. The objectives of this study were to measure (i) P runoff and (ii) forage yield and N uptake from small plots fertilized with composted and fresh poultry litter. Two composting studies, aerated using mechanical turning, were conducted in consecutive years. Composted litter was collected at the completion of each study for use in runoff studies. Treatments in runoff studies included an unfertilized control, fresh (uncomposted) poultry litter, and litter composted with no amendment, H3PO4, alum, or a microbial mixture. An additional treatment, litter composted with alum plus the microbial mixture, was evaluated during the first year. Fertilizer treatments were applied at rates equivalent to 8.96 Mg ha(-1) and rainfall simulators were used to produce a 5 cm h(-1) storm event. Composted poultry litter, regardless of treatment, had higher total P concentrations than fresh poultry litter. Composting poultry litter resulted in reductions of N/P ratios by as much as 51%. Soluble reactive P concentrations were lowest in alum-treated compost, which reduced soluble P concentrations in runoff water by as much as 84%. Forage yields and N uptake were greatest from plots fertilized with fresh poultry litter. Composting poultry litter without the addition of C sources can increase P concentrations in the end product and surface runoff. This study also indicated that increased rates of composted poultry litter would be required to meet equivalent N rates supplied by fresh poultry litter.

Recovery of Nitrogen in Fresh and Pelletized Poultry Litter by Rice

The N‐fertilizer value of preplant incorporated poultry litter for rice (Oryza sativa L.) grown using the direct‐seeded, delayed‐flood (DF) production system is unknown. The research objective was to compare preplant incorporated fresh (FPL) and pelleted (PPL) poultry litter with urea applied preflood to determine the urea‐nitrogen (N) equivalence of poultry litter for rice. Fresh and pelleted litter were preplant incorporated at total‐N rates ranging from 34 to 270 kg N ha−1 and compared with urea applied preflood at rates ranging from 34 to 168 kg N ha−1 at five site‐years on silt loam soils. Net‐N uptakes and grain yields between FPL and PPL were similar, but significantly lower when compared with urea applied preflood, regardless of site‐year. By heading, when averaged across all N rates and site‐years, rice recovery of the urea‐N applied preflood averaged 76%. In contrast, the apparent recovery of N applied as FPL or PPL averaged only 14%. Net‐grain yields for rice fertilized with urea increased nonlinearly as N rate increased with near maximal yields produced with ≥101 kg urea‐N ha−1 Grain yields for FPL and PPL increased linearly and approached the near maximal yields produced with urea‐N only when 270 kg total‐N ha−1 was applied. Based on net grain yield, multiplying the total‐N content in FPL and PPL by 0.25 reasonably estimates its equivalence to urea applied preflood. Recommended preflood urea‐N rates should be decreased by 0.25 times the total N applied as poultry litter.

Effect of Poultry Litter to Water Ratios on Extractable Phosphorus Content and its Relation to Runoff Phosphorus Concentrations

Source factors with regard to phosphorus (P) loss in runoff waters are often soil test P and P content of fertilisers applied. More recently, water extractable P (WEP) fractions in fertilisers and animal manure have been the focus of many field and plot-scale studies. This study evaluated changes in the WEP content of six poultry litters by varying the extraction ratio from 1:10 (20 g fresh poultry litter to 200 ml water) to 1:200 (1 g fresh poultry litter to 200 ml water), and also the relation between WEP content determined at these different ratios and P concentrations in runoff water collected during rainfall simulations. Six different poultry litters were surface-applied at equivalent total P (TP) application rates (∼67 kg [TP] ha−1) to 1·52 by 6·10 m grass plots on a 5% slope which received artificial rainfall at 5 cm h−1 until 30 min of continuous runoff was observed. Four plots were used per treatment including four control plots (no poultry litter application). Water-extractable P content of the various poultry litters increased with a decrease in the amount of poultry litter used in the extraction, i.e. from an extraction ratio of 1:10 to 1:200. However, these results also suggest that the 1:10 extraction ratio may extract different fractions of WEP compared to the 1:200 extraction ratio, and that some variability in dry weight extraction ratios existed when using fresh poultry litter. Water-extractable P application rates were positively correlated to P concentrations in runoff waters from the small plots. This study reaffirmed the importance of WEP content of poultry litter when determining the potential for P loss in surface runoff but demonstrated differences in the relation between runoff soluble reactive P (SRP) concentrations and WEP application rates related to the runoff to rainfall ratio.