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Repeated broiler litter application on agricultural lands can cause nutrient enrichment of subsurface effluent, especially with the existence of preferential flow through soil macropores. Previous studies quantifying soil macropores have not attempted to establish a connection of soil macropore characteristics with the subsurface nutrient (nitrogen [N] and phosphorus [P]) losses, across different topographical locations in the field. This study investigated the effect of broiler litter application and preferential flow on subsurface nutrient transport (N and P) at different topographical positions (upslope, midslope, and downslope) in a no‐till pasture field located in Alabama, USA. Twelve intact soil columns (150 mm id and 500 mm length) were used, and the nutrient leaching measurements from laboratory experiments were linked to soil macropore characteristics quantified using X‐ray computed tomography image analysis and solute transport modeling. Treatments included surface broadcast broiler litter (5 Mg ha−1, on dry basis) and unamended control. Leachates were analyzed for dissolved reactive P (DRP), total P (TP), and nitrate + nitrite‐N (NO3− + NO2−–N). The bromide breakthrough curves provided evidence of preferential flow in all columns. Litter application significantly increased leachate P concentrations, and average TP and DRP concentrations were significantly higher in the leachate from upslope columns compared to those at downslope location. The NO3−–N concentrations in leachate exceeded the US EPA drinking water standard of 10 mg L−1 in all the treatment columns. The highest flow‐weighted mean concentrations of TP and DRP, at 2.7 and 2.5 mg L−1, respectively, were recorded in the upslope columns. Soil physicochemical properties and nutrient leaching losses varied substantially across topographical positions, indicating a need for variable litter application rates to reduce P build‐up and subsequent leaching in vulnerable locations within the field. The relevance of the effect of topographic position on nutrient leaching found in this study should be further tested by investigating a wider range of slopes and soil types in pastures. Core Ideas: Phosphorus and nitrogen concentrations in the leachate varied as a function of slope position.Breakthrough curves and X‐ray computed tomography (CT) analysis provided evidence of preferential flow.Solute transport was well‐fitted by the two‐region physical nonequilibrium model.Broiler litter application significantly increased phosphorus leaching under saturated conditions. [ABSTRACT FROM AUTHOR]

Broiler litter (BL), a byproduct of the broiler (Gallus gallus sp.) production cycle, can be regarded as a beneficial organic source to supply essential nutrients for crop growth. Understanding BL nutrient mineralization helps producers better manage nutrients on farms. However, the effects of BL age (length of time BL stays in poultry house before it is cleaned out, also known as the clean out frequency of BL) and application rate on the mineralization of BL nutrients are still poorly understood. Therefore, a 150‐day laboratory incubation study investigated the influence of BL age (6, 18, and 30 months) and application rate (5 and 10 Mg ha−1) on nutrient mineralization. The experimental design was a completely randomized design with three replications. Soil samples were collected at day 0, 10, 30, 60, 90, 120, and 150 and analyzed for nitrogen (N) species nitrate, ammonium, total N, and water‐extractable nutrients (water‐extractable phosphorus, potassium [WEK], calcium [WECa], magnesium [WEMg], iron [WEFe], copper [WECu], zinc (WEZn), boron [WEB], and manganese [WEMn]). Results showed that BL nutrient mineralization was affected by BL age or application rate, except WEFe. A greater amount of nitrate‐N was released during the first month, suggesting faster nitrification during the first 30 days after application. Mineral N (sum of nitrate‐ and ammonium‐N) release was more significant with the increasing age of BL and application rate. Greater availability of WEK, WECa, WEMg, and WEB was found in 18‐ and 30‐month BL from 10 Mg ha−1, and lowest in 6‐month BL from 5 Mg ha−1, whereas 6‐month BL with 10 Mg ha−1 has the greatest WECu. Our results suggested that older BL (30 months) with a greater application rate (10 Mg ha−1) had greater nutrient supply potential. Core Ideas: Broiler litter nutrient mineralization was studied to evaluate the effect of age and application rate.Except for water‐extractable iron, BL age or application rate had an impact on the nutrient mineralization.Water‐extractable K, Ca, Mg, and B were more readily available in 18‐ and 30‐month than 6‐month cleanouts.The most evident nitrification and WEP immobilization occurred within a month of BL application. [ABSTRACT FROM AUTHOR]

• FGD-gypsum as an in-house PL amendment to reduce P solubility was investigated. • Commercial PLT was less effective in reducing P solubility compared to FGD-gypsum treatment. • Toxic metal concentrations were negligible in FGD gypsum and have no environmental concern. • FGD-gypsum reduced soluble P by 58–67% compared to untreated litter in 1st water extraction. • Shift in P fractions in PL was observed due to FGD-gypsum addition. Phosphorus (P) runoff from agricultural lands receiving poultry litter (PL) poses a major environmental challenge. Application of flue-gas-desulfurization (FGD)-gypsum produced from coal power plants in agricultural lands has shown promise to reduce P losses. However, no information is available about the effectiveness of FGD-gypsum addition in reducing P solubility when applied as an in-house amendment. Hence, the objectives of this study were to understand a) effectiveness of FGD-gypsum as a litter amendment in reducing P loss risk; and b) how FGD-gypsum amendment in PL alters the distribution of P forms. Broiler chickens were raised for five flocks in seven individual litter treatments replicated four times in a randomized complete block design. Based on the FGD-gypsum addition, the PL treatments were broadly classified as FGD-gypsum treated and untreated. Toxic metal concentrations were analyzed in FGD-gypsum as well as the treatments. Sequential water extractions were performed to understand P solubility. Litter P fractionation was performed to identify bioavailable P (Water-P), labile P (NaHCO 3 -P), aluminum/iron chemisorbed P (NaOH-P), and mineral occluded P (HCl-P). Results indicated significantly higher soluble P in all untreated than in all FGD-gypsum treated litters in the initial water extraction. The FGD-gypsum treated litters reduced soluble P by 58 to 67% in the 1st water extraction compared to untreated litters. Fractionation study revealed lower proportion of Water-P and higher proportion of NaHCO 3 -P and HCl-P in all FGD-gypsum treated than in untreated litters. This study suggests reuse of FGD-gypsum in broiler houses can help reduce P mobility without any toxic metals concerns. [ABSTRACT FROM AUTHOR]

The nutrient composition of a corn (Zea Mays L.) ear impacts its nutritional value and potential use as human food and animal feed. Whether the application of broiler litter (BL) can enrich corn ears with supplied mineral elements compared to conventional fertilizers is not well studied. A 2‐year study investigated the mineral composition of corn ears as affected by nutrient source (BL or urea), application rate (0, 168, and 336 kg total N ha−1), and application time (single or split) at three locations in Alabama, USA. Corn ear samples were collected at physiological maturity each year and analyzed for the total nutrient contents of 11 mineral elements. Regardless of application rate and application time, BL did not increase any elemental concentrations in the corn ear. Corn fertilized with urea had the highest corn ear concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), manganese (Mn), iron (Fe), and copper (Cu) across all locations. Corn ear N concentration depended on the soil's level of plant‐available N (PAN). Corn ear concentrations of P, K, and other mineral elements were not dependent on their soil levels but the corn ear N concentration. Thus, growing corn with an adequate supply of PAN in soil, irrespective of the source ensures maximum accumulation of corn ear N and other mineral elements. Core Ideas: Broiler litter did not elevate corn ear nutrient levels.Urea produced the highest corn ear concentrations of N, P, K, Ca, Mg, Zn, Mn, Fe, and Cu.Concentration of N, P, and other mineral elements in corn ear depends on soil plant‐available N level.Optimum N fertilizations, regardless of nutrient source, ensure maximum ear mineral element levels in corn production. [ABSTRACT FROM AUTHOR]

Use of broiler litter (BL) for agronomic purposes requires balancing the amount of nitrogen (N) needed to maximize crop yield while reducing environmental N footprints. This 2‐yr study (2018–2019) compared the effects of N source (BL or urea), application rate [0, 168, and 336 kg total N ha–1), and application timing (single or split) on corn (Zea mays L.) yield and environmental nitrogen loss (ENL) on three Alabama soil types. A field‐scale partial N budget was developed by accounting for known N inputs and outputs. The difference between the input and output in the partial N budget was considered as ENL, which comprised of N losses via runoff, leaching, volatilization, and denitrification. Application of BL increased corn yield relative to urea at only one site. At the responsive site, BL application rate had no significant effect on corn yield, but pre‐plant single application of BL produced 52% greater corn yield compared with split application. At other two sites where yield was lower for corn receiving BL, corn yield increased significantly with increasing BL application rate. Total N loss to the environment ranged between 32 and 52% of the N input. The influence of N source on ENL varied by site however losses increased with increasing N fertilization rates. Application timing did not influence ENL at two of three sites. This study showed that a lower application rate (168 kg ha–1) of BL prior to planting was a better management strategy for increasing corn yield, while reducing environmental N loss. Core Ideas: Broiler litter increased corn yield relative to urea only where soil N was nonlimiting.Split applications of broiler litter produced lower corn yield than single pre‐plant applications.Total N loss to the environment ranged from 32 to 52% of the N input.Nitrogen losses to the environment increased with increasing N application rate. [ABSTRACT FROM AUTHOR]

[Display omitted] • P fractionation in poultry litter impacted soils identified intermediately available P i as the dominant pool in 0–5 cm soils. • Surface soils had lower P sorption capacity and higher desorption potential compared to the soils in lower depths. • P saturation ratio (PSR) was strongly related to P sorption-desorption parameters. • PSR can be effectively used to predict P sorption-desorption parameters for Piedmont soil region. [ABSTRACT FROM AUTHOR]

Broiler litter (BL) has the potential to be used as an alternative multi-nutrient source for soybean (Glycine max L.) production. While previous research on soybean yield response to BL has reported inconsistent results, the effects of BL application on soybean seed nutrient concentrations are largely unknown or less studied. The objective of this two-year field study was to investigate the effect of BL application on soybean yield and seed nutrient content in three different soil types and production environments. To pursue the objective, a field experiment was established in 2018 in a Compass loamy sand with four BL rates (0, 2.2, 5.6, and 11.2 Mg BL ha−1). In 2019, the study was expanded to include two additional soil types (Decatur silty clay loam and Dothan fine sandy loam) totaling four site years. The experimental design at each site was a randomized complete block with four replications. Application of BL had no impact on soybean yield in the first year, regardless of application rate and soil type. In the second year of BL application, soybean yield was 43% higher overall compared to no BL plots on a Compass loamy sand. However, soybean yield with the application of 5.6 or 11.2 Mg BL ha−1 was not statistically different from that at 2.2 Mg BL ha−1. Soybean seed Ca and B concentrations changed significantly among the treatments; however, the change was not consistent across the sites. Consecutive year application of 11.2 Mg BL ha−1 yr−1 produced the highest seed K and Cu concentrations. The results of this research suggest that repeated BL application can boost soybean yield and potentially enrich seed with selected nutrients. [ABSTRACT FROM AUTHOR]

Highlights • Leachates from fresh and stored poultry litter were anaerobically digested. • Leachates had greater biomethane potential than whole litter. • Stored litter produced less biomethane but higher mineralized nutrients than fresh. • Leaching removed significant amounts of N and P nutrients from litter. • Digestates are suitable for fertigation or algae cultivation. Abstract Anaerobic digestion of poultry litter is a potentially sustainable means of stabilizing this waste while generating biogas. However, technical challenges remain including seasonality of litter production, low C/N ratios, limited digestibility of bedding, and questions about transformation of nutrients during digestion. This study investigated biogas production and nutrient transformations during anaerobic digestion of poultry litter leachate and whole litter. Use of fresh litter collected from within the house was also compared to waste litter cake that was stored outdoors on the farm. The results showed that litter leachates had higher biomethane potential (0.24–0.30 L/gVS) than whole litter (0.15–0.16 L/gVS) and the insoluble bedding material left after leaching (0.08–0.13 L/gVS). Leachates prepared from waste litter cake had lower uric acid and higher acetic acid concentrations than fresh litter indicating that decomposition had occurred during storage. Consequently, waste litter cake had faster initial biogas production but lower final biogas yields compared to fresh litter. In all reactors, uric and acetic acids were completely consumed during digestion, phosphate levels decreased but ammonium levels increased. The results demonstrate that poultry litter leachate is amenable to digestion despite a low C/N ratio and that the remaining insoluble bedding material has been partially stripped of its nutrients. Moreover, litter can be stored prior to digestion but some losses in biomethane potential should be expected due to decomposition of organics during storage. [ABSTRACT FROM AUTHOR]

Poultry litter waste is typically land-applied as a soil amendment but repeated application in the vicinity of poultry houses has led to phosphorus accumulation in soil. Such application can also lead to runoff that causes eutrophication. Most farmers store litter under dry conditions or compost the litter prior to land application, but it is not clear if these approaches are best from a nutrient management-perspective. The objective of this study was to investigate the effects of moisture content and active aeration on soluble mineral forms of nitrogen and phosphorus in poultry litter incubated for roughly one month. Mineral forms of nutrients are immediately plant-available upon field application and also most conducive to low-cost stripping and recovery methods. Litters were incubated at 50% and 70% moisture content with and without active aeration. Litter aeration led to significant ammonia losses and a consequent decline in litter pH but it had no effect on phosphate solubility. Moisture content during litter incubation governed the levels of plant-available phosphate and nitrification. High (70%) moisture led to 41%–78% higher plant-available phosphate (4.2–4.8 mg/g litter) compared to litters with 50% moisture content (2.7–3.0 mg/g litter). In contrast, the 50% moisture litters experienced 5–6 fold higher levels of nitrification (0.11–0.12 mg NO 3 -N/g litter) than litters with 70% moisture content (0.02 mg NO 3 -N/g litter), regardless of aeration. The implication is that lower-moisture litter storage is likely best for field application because phosphate is less soluble under neutral-alkaline conditions and therefore less likely to end up in runoff. In contrast, higher-moisture litter storage may be amenable to low-cost processes to leach and recover phosphate from litter. [Display omitted] • Effect of moisture content and aeration on litter nutrients was assessed. • Aeration led to ammonia volatilization and decline in pH. • 70% moisture led to 41–78% higher plant available phosphate than 50% moisture. • High moisture litter conducive to leaching and precipitation of phosphate. [ABSTRACT FROM AUTHOR]