@article{kulesza_maguire_xia_ray_knowlton_2022, title={Effect of temperature, pH, and soil texture on pirlimycin fate in dairy manure-amended soils}, volume={11}, ISSN={["1537-2537"]}, url={https://doi.org/10.1002/jeq2.20410}, DOI={10.1002/jeq2.20410}, abstractNote={Antibiotics applied to soil through application of manure are of increasing concern due to their adverse environmental impacts, including their potential contribution to the development of antibiotic resistance in the environment. Two 90-d laboratory incubation studies were conducted to determine the effects of temperature (10 or 21 °C), pH (5, 7, 9), and soil texture (sandy loam, loam) on the persistence of two antibiotics (pirlimycin and cephapirin) applied to soils with dairy manure amendment. Dairy manure from treated and untreated cows was used as the source for this study. However, cephapirin was not detected in manure used for the study. Initial manure pH affected pirlimycin concentration of the manure, and there were differences in initial soil concentration between soil types. In the temperature experiment, pirlimycin concentration was significantly affected by temperature and soil type. In the 10 °C treatments, pirlimycin concentration initially decreased at 7 d but increased to levels similar to 0 d concentrations at 14 d, indicating possible deconjugation of pirlimycin ribonucleotide adducts in the manure applied. Although the loam soil type had a higher pirlimycin concentration in the temperature experiment at 0 d and 14 d, concentrations decreased below the sandy loam soil at 56 d and continued in the 90-d sampling period. Pirlimycin dissipation from dairy manure-amended soils was enhanced by higher temperature and finer soil texture, both of which could affect development of resistance genes if soil microbes are exposed to pirlimycin for longer periods of time.}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Kulesza, Stephanie B. and Maguire, Rory and Xia, Kang and Ray, Partha and Knowlton, Katharine}, year={2022}, month={Nov} }
 @article{zhang_antonangelo_grove_osmond_slaton_alford_florence_huluka_hardy_lessl_et al._2021, title={Variation in soil-test-based phosphorus and potassium rate recommendations across the southern USA}, volume={6}, ISSN={["1435-0661"]}, DOI={10.1002/saj2.20280}, abstractNote={Abstract Thirteen states associated with the Southern Extension and Research Activities Information Exchange Group‐6 (SERA‐IEG‐6) agreed to share their soil test based P and K rate recommendations for nine major crops. The objectives were to compare fertilizer P and K rate recommendations, to look for opportunities to rationalize similar recommendations across state lines, and to examine challenges to the development of a cooperative regional approach to P and K recommendations. Mehlich‐3 (eight states), Mehlich‐1 (five states), or Lancaster (one state) extractions were the basis of plant available soil P (STP) and K (STK) assessment. Fertilizer recommendation philosophies (sufficiency, build and maintain, and/or hybrid) variation among the states might be the main reason behind such discrepancies. Although a few similarities in P and K rate recommendations were found, the different philosophies, numerical presentations, and extraction procedures drove important recommendation differences. Widespread adoption of the Mehlich‐3 extraction procedure has not reduced variation in fertilizer P and K rate recommendations among the states. Instead, for states using Mehlich 3, soil test critical concentrations ranged from 30 to 75 mg P kg –1 and 60 to 175 mg K kg –1 for corn ( Zea mays L.) grain and warm‐season grass hay production. The adoption of uniform soil testing terminology, sample collection guidelines, extraction methods, and interpretations across common physiographic regions, soils, and state lines remains a challenge. Differences arise because of the different soil orders and properties, climate conditions, and resulting crop responses to added P and K fertilizers. Such differences in soil‐test‐based fertilizer P and K recommendations are state specific and highlight needs to examine the soil testing and recommendation process, make soil test results end‐user friendly, and, when appropriate, standardize fundamental information used in the soil testing guidelines.}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Zhang, Hailin and Antonangelo, Joao and Grove, John and Osmond, Deanna and Slaton, Nathan A. and Alford, Shannon and Florence, Robert and Huluka, Gobena and Hardy, David Herring and Lessl, Jason and et al.}, year={2021}, month={Jun} }
 @article{leytem_kwanyuen_plumstead_maguire_brake_2008, title={Evaluation of Phosphorus Characterization in Broiler Ileal Digesta, Manure, and Litter Samples: <sup>31</sup>P‐NMR vs. HPLC}, volume={37}, ISSN={0047-2425 1537-2537}, url={http://dx.doi.org/10.2134/jeq2007.0134}, DOI={10.2134/jeq2007.0134}, abstractNote={Abstract Using 31‐phosphorus nuclear magnetic resonance spectroscopy ( 31 P‐NMR) to characterize phosphorus (P) in animal manures and litter has become a popular technique in the area of nutrient management. To date, there has been no published work evaluating P quantification in manure/litter samples with 31 P‐NMR compared to other accepted methods such as high performance liquid chromatography (HPLC). To evaluate the use of 31 P‐NMR to quantify myo ‐inositol hexa kis phosphate (phytate) in ileal digesta, manure, and litter from broilers, we compared results obtained from both 31 P‐NMR and a more traditional HPLC method. The quantification of phytate in all samples was very consistent between the two methods, with linear regressions having slopes ranging from 0.94 to 1.07 and r 2 values of 0.84 to 0.98. We compared the concentration of total monoester P determined with 31 P‐NMR with the total inositol P content determined with HPLC and found a strong linear relationship between the two measurements having slopes ranging from 0.91 to 1.08 and r 2 values of 0.73 to 0.95. This suggests that 31 P‐NMR is a very reliable method for quantifying P compounds in manure/litter samples.}, number={2}, journal={Journal of Environmental Quality}, publisher={Wiley}, author={Leytem, A. B. and Kwanyuen, P. and Plumstead, P. W. and Maguire, R. O. and Brake, J.}, year={2008}, month={Mar}, pages={494–500} }
 @article{plumstead_leytem_maguire_spears_kwanyuen_brake_2008, title={Interaction of Calcium and Phytate in Broiler Diets. 1. Effects on Apparent Prececal Digestibility and Retention of Phosphorus}, volume={87}, ISSN={0032-5791}, url={http://dx.doi.org/10.3382/ps.2007-00231}, DOI={10.3382/ps.2007-00231}, abstractNote={Phytate P utilization from soybean meal (SBM) included in broiler diets has been shown to be poor and highly dependent on dietary Ca intake. However, the effect of Ca on P utilization and on the optimal ratio of Ca to nonphytate P (Ca:NPP) when diets contained varying levels of phytate has not been clearly shown and was the objective of this research. A factorial treatment structure was used with 4 dietary Ca levels from 0.47 to 1.16% and 3 levels of phytate P (0.28, 0.24, and 0.10%). Varying dietary phytate P levels were obtained by utilizing SBM produced from 3 varieties of soybeans with different phytate P concentrations. Ross 508 broiler chicks were fed 1 of 12 diets from 16 to 21 d of age. Excreta were collected from 16 to 17 d and from 19 to 20 d of age and ileal digesta was collected at 21 d of age. Apparent prececal P digestibility decreased when dietary Ca concentration increased and was higher when diets contained low-phytate SBM. The apparent digestibility of Ca and percentage of phytate P hydrolysis at the distal ileum were not reduced when dietary phytate P concentration increased. Including low-phytate SBM in diets reduced total P output in the excreta by 49% compared with conventional SBM. The optimum ratio of Ca:NPP that resulted in the highest P retention and lowest P excretion was 2.53:1, 2.40:1, and 2.34:1 for diets with 0.28, 0.24, and 0.10% phytate P. These data suggested that increased dietary Ca reduced the extent of phytate P hydrolysis and P digestibility and that the optimum Ca:NPP ratio at which P retention was maximized was reduced when diets contained less phytate P.}, number={3}, journal={Poultry Science}, publisher={Elsevier BV}, author={Plumstead, P.W. and Leytem, A.B. and Maguire, R.O. and Spears, J.W. and Kwanyuen, P. and Brake, J.}, year={2008}, month={Mar}, pages={449–458} }
 @article{leytem_plumstead_maguire_kwanyuen_burton_brake_2008, title={Interaction of Calcium and Phytate in Broiler Diets. 2. Effects on Total and Soluble Phosphorus Excretion}, volume={87}, ISSN={0032-5791}, url={http://dx.doi.org/10.3382/ps.2007-00229}, DOI={10.3382/ps.2007-00229}, abstractNote={Dietary Ca has been reported to influence the amount of phytate excreted from broilers and affect the solubility of P in excreta. To address the effects of dietary Ca and phytate on P excretion, 12 dietary treatments were fed to broilers from 16 to 21 d of age. Treatments consisted of 3 levels of phytate P (0.10, 0.24, and 0.28%) and 4 levels of Ca (0.47, 0.70, 0.93, and 1.16%) in a randomized complete block design. Feed phytate concentrations were varied by formulating diets with 3 different soybean meals (SBM): a low-phytate SBM, a commercial SBM, and a high phytate Prolina SBM having phytate P concentrations of 0.15 to 0.51%. Fresh excreta was collected from cages during 2 separate 24-h periods; collection I commenced after the start of dietary treatments (16 to 17 d) and collection II followed a 3-d adaptation period (19 to 20 d). Ileal samples were also collected at 21 d. Excreta samples were analyzed for total P, water soluble P (WSP), and phytate P, whereas ileal samples were analyzed for total P and phytate P. Results indicated that excreta total P could be reduced by up to 63% and WSP by up to 66% with dietary inclusion of low-phytate SBM. There was a significant effect of dietary Ca on both the excreta WSP and the ratio of WSP:total P. As dietary Ca increased, the excreta WSP and WSP:total P decreased, with the effects being more pronounced following a dietary adaptation period. There was a linear relationship between the slope of the response in WSP to dietary Ca and feed phytate content for excreta from collection II (r(2) = 0.99). There was also a negative correlation between excreta phytate concentration and excreta WSP during both excreta collections. The response in WSP to dietary manipulation was important from an environmental perspective because WSP in excreta has been related to potential for off-site P losses following land application.}, number={3}, journal={Poultry Science}, publisher={Elsevier BV}, author={Leytem, A.B. and Plumstead, P.W. and Maguire, R.O. and Kwanyuen, P. and Burton, J.W. and Brake, J.}, year={2008}, month={Mar}, pages={459–467} }
 @article{ruiz_ruiz_gernat_grimes_murillo_wineland_anderson_maguire_2008, title={The effect of quicklime (CaO) on litter condition and broiler performance}, volume={87}, ISSN={["0032-5791"]}, DOI={10.3382/ps.2007-00101}, abstractNote={High levels of phosphorus and pathogens in runoff are 2 major concerns following manure applications to fields. Phosphorus losses from fields following manure applications have been linked to the solubility of phosphorus in manure; therefore, by decreasing manure phosphorus solubility, a decrease in phosphorus loss in runoff should be apparent. The objective of this research was to develop a process using quicklime that would result in reduced phosphorus solubility and bacteria counts in broiler litter. The 4 litter treatments evaluated were T1, new wood shavings without the addition of quicklime; T2, used, untreated broiler litter; T3, used litter with 10% quicklime (based on the weight of the litter); and T4, used litter with 15% quicklime (based on the weight of the litter). Body weight, cumulative feed consumption, and feed conversion (feed:BW) were determined on a weekly basis through 42 d of age. Mortality was recorded daily. Carcass weights and percentages of carcass yield without giblets were determined prechill. Litter pH, total phosphorus, nitrogen, soluble phosphorus, litter moisture (%), and total plate counts were measured for each litter treatment on d 7 and 42 after bird placement. No significant differences were found for BW, feed consumption, feed conversion, mortality, carcass weight, or carcass yield. No breast or footpad blisters were observed. On d 7, 15% quicklime had higher (P < 0.001) pH (11.2) when compared with the other treatments. Percentages of phosphorus and nitrogen were lower (P < 0.001) for new wood shavings in comparison with the used litter treatments. Soluble phosphorus (ppm) was lower (P < 0.001) for 15% quicklime (2.75) when compared with new wood shavings (42.2), untreated broiler litter (439.2), and 10% quicklime (35.0). Although not significant, 15% quicklime had lower total plate counts (cfu/g) in comparison with the other treatments on d 1 and 10 postmixing and at 7 d after bird placement. Litter conditions on d 42 after bird placement were similar. We concluded that the use of quicklime as a treatment for broiler litter would initially reduce nitrogen and soluble phosphorus and bacteria counts without negatively affecting bird productivity.}, number={5}, journal={POULTRY SCIENCE}, author={Ruiz, V. and Ruiz, D. and Gernat, A. G. and Grimes, J. L. and Murillo, J. G. and Wineland, M. J. and Anderson, K. E. and Maguire, R. O.}, year={2008}, month={May}, pages={823–827} }
 @article{maguire_crouse_hodges_2007, title={Diet modification to reduce phosphorus surpluses: A mass balance approach}, volume={36}, ISSN={["0047-2425"]}, DOI={10.2134/jeq2006.0551}, abstractNote={Diet modification to reduce phosphorus (P) concentrations in manures has been developed in response to environmental concerns over P losses from animal agriculture to surface waters. We used USDA-NASS statistics on animal numbers and crop production to calculate county scale mass balances for manure P production, P removed in harvested portion of crops, and the potential effects of diet modification. Although spreading manure evenly over all crop acreage within a county is unlikely to occur, these calculations give a good indication as to the impact diet modification to reduce P can have at a regional or national scale. There was a high degree of regional variability in manure P surpluses (e.g., with the large crop acreages in the grain belt leading to large P offtake in crops preventing most P surpluses). In 89% of counties, there was a deficit of manure P relative to crop P removal; therefore there was a manure P surplus in 11% of counties. Diet modification decreased the percentage of states with a manure P surplus from 11 to 8%, a decrease of approximately 27%. Diet modification decreased the percentage of counties with the greatest surpluses of manure P (>30 kg ha(-1)) from 3% of all counties to 1%. Diet modification to decrease manure P is an important part of strategies to alleviate environmental concerns associated with surplus manure P in many areas, but additional strategies to deal with manure P surpluses are needed in some areas.}, number={5}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Maguire, R. O. and Crouse, D. A. and Hodges, S. C.}, year={2007}, pages={1235–1240} }
 @article{leytem_plumstead_maguire_kwanyuen_brake_2007, title={What Aspect of Dietary Modification in Broilers Controls Litter Water‐Soluble Phosphorus}, volume={36}, ISSN={0047-2425 1537-2537}, url={http://dx.doi.org/10.2134/jeq2006.0334}, DOI={10.2134/jeq2006.0334}, abstractNote={ABSTRACT Environmental concerns about phosphorus (P) losses from animal agriculture have led to interest in dietary strategies to reduce the concentration and solubility of P in manures and litters. To address the effects of dietary available phosphorus (AvP), calcium (Ca), and phytase on P excretion in broilers, 18 dietary treatments were applied in a randomized complete block design to each of four replicate pens of 28 broilers from 18 to 42 d of age. Treatments consisted of three levels of AvP (3.5, 3.0, and 2.5 g kg −1 ) combined with three levels of Ca (8.0, 6.9, and 5.7 g kg −1 ) and two levels of phytase (0 and 600 phytase units [FTU]). Phytase was added at the expense of 1.0 g kg −1 P from dicalcium phosphate. Fresh litter was collected from pens when the broilers were 41 d of age and analyzed for total P, soluble P, and phytate P as well as P composition by 31 P nuclear magnetic resonance (NMR) spectroscopy. Results indicated that the inclusion of phytase at the expense of inorganic P or reductions in AvP decreased litter total P by 28 to 43%. Litter water‐soluble P (WSP) decreased by up to 73% with an increasing dietary Ca/AvP ratio, irrespective of phytase addition. The ratio of WSP/total P in litter decreased as the dietary Ca/AvP ratio increased and was greater in the phytase‐amended diets. This study indicated that while feeding reduced AvP diets with phytase decreased litter total P, the ratio of Ca/AvP in the diet was primarily responsible for effects on WSP. This is important from an environmental perspective as the amount of WSP in litter could be related to potential for off‐site P losses following land application of litter.}, number={2}, journal={Journal of Environmental Quality}, publisher={Wiley}, author={Leytem, A. B. and Plumstead, P. W. and Maguire, R. O. and Kwanyuen, P. and Brake, J.}, year={2007}, month={Mar}, pages={453–463} }
 @article{bond_maguire_havlin_2006, title={Change in soluble phosphorus in soils following fertilization is dependent on initial Mehlich-3 phosphorus}, volume={35}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2005.0404}, abstractNote={There is a lack of information on how fertilization and initial Mehlich-3 phosphorus (M3P) interact to affect water soluble P (WSP) in soils. Our objectives were to (i) quantify the relationship between WSP and M3P for four textural diverse benchmark soils of North Carolina (NC) and (ii) quantify the change in WSP concentrations following P additions to soils over a wide range of initial M3P. Soils known to represent a wide range in M3P were collected from an Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults), Wasda muck (fine-loamy, mixed, semiactive, acid, thermic Histic Humaquepts), Georgeville silt loam (fine, kaolinitic, thermic Typic Kanhapludults), and Pacolet sandy clay loam (fine, kaolinitic, thermic Typic Kanhapludults) and analyzed for M3P, Fe, Al, and WSP. An incubation study was also conducted where four samples representing a range in M3P from each series were fertilized at rates of 150 and 300 kg P ha(-1), and WSP was measured at 1, 7, and 21 d after fertilization. The Wasda muck exhibited a change point at 115 mg P kg(-1) across a broad range of M3P concentrations (60-238 mg kg(-1)) while Autryville, Georgeville, and Pacolet series (with ranges in M3P of 32-328, 119-524, 0-1034 mg P kg(-1), respectively) maintained linear relationships between WSP and M3P. For the fertilized soils, significant increases in WSP occurred regardless of P rate. Yet, WSP concentrations were greater in soils with greater initial M3P. Thus, these data suggest that shifting animal waste applications to fields of relatively lower M3P concentrations would have an immediate impact on reducing risk for P losses, if all other factors are equal.}, number={5}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Bond, C. Ryan and Maguire, R. O. and Havlin, J. L.}, year={2006}, pages={1818–1824} }
 @article{baum_pierzynski_kleinman_kovar_maguire_moore_zhang_2006, title={Evaluating the influence of storage time, sample-handling method, and filter paper on the measurement of water-extractable phosphorus in animal manures}, volume={37}, ISSN={["1532-2416"]}, DOI={10.1080/00103620500449328}, abstractNote={Abstract Surface‐applied manures create a potential phosphorus (P) runoff hazard, especially when unincorporated. In such cases, the concentration of water‐extractable P in the manure has been correlated to soluble P concentrations in runoff. This study evaluated the influence of holding time, sample‐handling procedure, and filtration method on measurement of the water‐extractable P content of manures in a 3×3×2 factorial arrangement of treatments. A two‐way interaction between holding time and sample‐handling procedure occurred for most samples. Six samples had water‐extractable P concentrations that were less than or equal to dried and dried/ground treatments. Only one sample had higher water‐extractable P concentrations for fresh than for dried and dried/ground treatments. When significant differences occurred as a result of the filtration method, results for Whatman No. 40 filters, with a larger pore size than 0.45 µm nitrocellulose membranes, were usually higher. There was no significant difference in the coefficient of variation across sample‐handling procedures, suggesting that efforts to dry and/or grind samples were not needed. These results support the adoption of a standardized protocol for measuring water‐extractable P in manures that represents the appropriate balance between the ease of implementation and the strength of the correlation to P runoff concentrations. Keywords: Water‐extractable phosphorusrunoffmanure Acknowledgments This is Contribution Number 04‐339‐J of the Kansas Agricultural Experiment Station, Manhattan, Kansas.}, number={3-4}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Baum, K and Pierzynski, G and Kleinman, P and Kovar, J and Maguire, R and Moore, P and Zhang, TQ}, year={2006}, pages={451–463} }
 @article{maguire_plumstead_brake_2006, title={Impact of Diet, Moisture, Location, and Storage on Soluble Phosphorus in Broiler Breeder Manure}, volume={35}, ISSN={0047-2425 1537-2537}, url={http://dx.doi.org/10.2134/jeq2005.0435}, DOI={10.2134/jeq2005.0435}, abstractNote={Decreasing dietary phosphorus (P) has the potential to reduce P excreted in manure and therefore alleviate the environmental degradations associated with intensive animal farming. We evaluated reducing dietary P for broiler breeders as an aid to reduce manure total and water soluble phosphorus (WSP). Broiler breeders were fed diets high and low in dietary P, with and without phytase, from 22 to 64 wk of age. At the end of the 42-wk production period, manure was collected from four locations in each two-thirds slat, one-third litter breeder pen: the litter scratch area, under the drinker in the slat area, under the feeder in the slat area, and in a clean area of the slat area away from feeder or drinker. After the initial sampling, all manure was removed from pens and representative samples were stored for 6 mo with and without feed mixed in to simulate the effect of spilled feed. Total P was determined on all pen samples, and moisture and WSP determined on the pen and stored samples. The manure collected under the drinker had much greater moisture due to spilled water. This was associated with much greater WSP in this location, showing the importance of good water management. The manure from under the feeder had similar WSP as manure from the clean area, so spilled feed did not significantly affect WSP. Dietary phytase either had no effect or significantly decreased manure WSP. However, addition of dietary phytase to the feed led to slightly elevated manure moisture. Since moisture was correlated with manure WSP this may explain some of the variability in WSP results between studies. Over 6 mo of storage WSP increased and generally followed the same ranking order at 168 d as at 1 d among the dietary treatments (high>high+phytase>low>low+phytase). Combining decreased dietary P and phytase reduced both manure total P and WSP by 42%. As total P and WSP are indicators of the long and short term impacts manure applications can have on P losses from manured soils, diet modification should be seen as environmentally beneficial.}, number={3}, journal={Journal of Environmental Quality}, publisher={Wiley}, author={Maguire, R. O. and Plumstead, P. W. and Brake, J.}, year={2006}, month={May}, pages={858–865} }
 @article{maguire_hesterberg_gernat_anderson_wineland_grimes_2006, title={Liming poultry manures to decrease soluble phosphorus and suppress the bacteria population}, volume={35}, ISSN={["1537-2537"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33646558633&partnerID=MN8TOARS}, DOI={10.2134/jeq2005.0339}, abstractNote={Stabilizing phosphorus (P) in poultry waste to reduce P losses from manured soils is important to protect surface waters, while pathogens in manures are an emerging issue. This study was conducted to evaluate CaO and Ca(OH)2 for killing manure bacterial populations (pathogens) and stabilizing P in poultry wastes and to investigate the influence on soils following amendment with the treated wastes. Layer manure and broiler litter varying in moisture content were treated with CaO and Ca(OH)2 at rates of 2.5, 5, 10, and 15% by weight. All treated wastes were analyzed for microbial plate counts, pH, and water-soluble phosphorus (WSP), while a few selected layer manures were analyzed by phosphorus X-ray absorption near edge structure (XANES). A loamy sand and a silt loam were amended with broiler litter and layer manure treated with CaO at rates of 0, 2.5, 5, 10, and 15% and soil WSP and pH were measured at times 1, 8, and 29 d. Liming reduced bacterial populations, with greater rates of lime leading to greater reductions; for example 10% CaO applied to 20% solids broiler litter reduced the plate counts from 793,000 to 6500 mL-1. Liming also reduced the WSP in the manures by over 90% in all cases where at least 10% CaO was added. Liming the manures also reduced WSP in soils immediately following application and raised soil pH. The liming process used successfully reduced plate counts and concerns about P losses in runoff following land application of these limed products due to decreased WSP.}, number={3}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Maguire, R. O. and Hesterberg, D. and Gernat, A. and Anderson, K. and Wineland, M. and Grimes, J.}, year={2006}, pages={849–857} }
 @article{mcgrath_sims_maguire_saylor_angel_turner_2005, title={Broiler diet modification and litter storage: Impacts on phosphorus in litters, soils, and runoff}, volume={34}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2004.0413}, abstractNote={ABSTRACT Modifying broiler diets to mitigate water quality concerns linked to excess phosphorus (P) in regions of intensive broiler production has recently increased. Our goals were to evaluate the effects of dietary modification, using phytase and reduced non‐phytate phosphorus (NPP) supplementation, on P speciation in broiler litters, changes in litter P forms during long‐term storage, and subsequent impacts of diets on P in runoff from litter‐amended soils. Four diets containing two levels of NPP with and without phytase were fed to broilers in a three‐flock floor pen study. After removal of the third flock, litters were stored for 440 d at their initial moisture content (MC; 24%) and at a MC of 40%. Litter P fractions and orthophosphate and phytate P concentrations were determined before and after storage. After storage, litters were incorporated with a sandy and silt loam and simulated rainfall was applied. Phytase and reduced dietary NPP significantly reduced litter total P. Reducing dietary NPP decreased water‐extractable inorganic phosphorus (IP) and the addition of dietary phytase reduced NaOH‐ and HCl‐extractable organic P in litter, which correlated well with orthophosphate and phytic acid measured by 31 P nuclear magnetic resonance (NMR), respectively. Although dry storage caused little change in P speciation, wet storage increased concentrations of water‐soluble IP, which increased reactive P in runoff from litter‐amended soils. Therefore, diet modification with phytase and reduced NPP could be effective in reducing P additions on a watershed scale. Moreover, efforts to minimize litter MC during storage may reduce the potential for dissolved P losses in runoff.}, number={5}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={McGrath, JM and Sims, JT and Maguire, RO and Saylor, WW and Angel, CR and Turner, BL}, year={2005}, pages={1896–1909} }
 @article{maguire_dou_sims_brake_joern_2005, title={Dietary Strategies for Reduced Phosphorus Excretion and Improved Water Quality}, volume={34}, ISSN={0047-2425 1537-2537}, url={http://dx.doi.org/10.2134/jeq2004.0410}, DOI={10.2134/jeq2004.0410}, abstractNote={ABSTRACT Cost effective feeding strategies are essential to deal with P surpluses associated with intensive animal agriculture and the consequent impact on water quality. Reduction of P overfeeding, use of feed additives to enhance dietary P utilization, and development of high available phosphorus (HAP) grains have all been shown to decrease fecal P excretion without impairing animal performance. Much progress has been made, but more research will be needed to refine these strategies to maximize reductions in P excretion while maintaining animal performance. Recent research has focused on the impact of modifying dietary P on the forms of P excreted and the mobility of P in soils amended with these manures, with strong treatment trends becoming evident in the literature. In general, dietary strategies have been developed that can effectively reduce the total P concentration in manures produced, and combining strategies usually leads to greater reductions than individual practices. However, the impact of different approaches on the solubility of P in manures and amended soils has been more variable. Soluble P remains of particular concern due to links between solubility of P in manure and P losses from manure‐amended soils. In this paper, we outline the major strategies for reducing dietary P in different species, review the literature on the impact of these approaches on P forms in manures and amended soils, and discuss the potential beneficial effects on animal agriculture and the environment.}, number={6}, journal={Journal of Environmental Quality}, publisher={Wiley}, author={Maguire, R. O. and Dou, Z. and Sims, J. T. and Brake, J. and Joern, B. C.}, year={2005}, month={Nov}, pages={2093–2103} }
 @article{maguire_sims_applegate_2005, title={Phytase supplementation and reduced-phosphorus turkey diets reduce phosphorus loss in runoff following litter application}, volume={34}, number={1}, journal={Journal of Environmental Quality}, author={Maguire, R. O. and Sims, J. T. and Applegate, T. J.}, year={2005}, pages={359–369} }
 @article{kleinman_sharpley_veith_maguire_vadas_2004, title={Evaluation of phosphorus transport in surface runoff from packed soil boxes}, volume={33}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2004.1413}, abstractNote={ABSTRACT Evaluation of phosphorus (P) management strategies to protect water quality has largely relied on research using simulated rainfall to generate runoff from either field plots or shallow boxes packed with soil. Runoff from unmanured, grassed field plots (1 m wide × 2 m long, 3–8% slope) and bare soil boxes (0.2 m wide and 1 m long, 3% slope) was compared using rainfall simulation (75 mm h −1 ) standardized by 30‐min runoff duration (rainfall averaged 55 mm for field plots and 41 mm for packed boxes). Packed boxes had lower infiltration (1.2 cm) and greater runoff (2.9 cm) and erosion (542 kg ha −1 ) than field plots (3.7 cm infiltration; 1.8 cm runoff; 149 kg ha −1 erosion), yielding greater total phosphorus (TP) losses in runoff. Despite these differences, regressions of dissolved reactive phosphorus (DRP) in runoff and Mehlich‐3 soil P were consistent between field plots and packed boxes reflecting similar buffering by soils and sediments. A second experiment compared manured boxes of 5‐ and 25‐cm depths to determine if variable hydrology based on box depth influenced P transport. Runoff properties did not differ significantly between box depths before or after broadcasting dairy, poultry, or swine manure (100 kg TP ha −1 ). Water‐extractable phosphorus (WEP) from manures dominated runoff P, and translocation of manure P into soil was consistent between box types. This study reveals the practical, but limited, comparability of field plot and soil box data, highlighting soil and sediment buffering in unamended soils and manure WEP in amended soils as dominant controls of DRP transport.}, number={4}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Kleinman, PJA and Sharpley, AN and Veith, TL and Maguire, RO and Vadas, PA}, year={2004}, pages={1413–1423} }
 @article{maguire_sims_saylor_turner_angel_applegate_2004, title={Influence of phytase addition to poultry diets on phosphorus forms and solubility in litters and amended soils}, volume={33}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2004.2306}, abstractNote={ABSTRACT Diet modification to decrease phosphorus (P) concentration in animal feeds and manures can reduce surpluses of manure P in areas of intensive animal production. We generated turkey and broiler litters from two and three flock trials, respectively, using diets that ranged from “high” to “low” in non‐phytate phosphorus (NPP) and some of which contained feed additives such as phytase. Phosphorus forms in selected litters were analyzed by sequential chemical fractionation and solution 31 P nuclear magnetic resonance (NMR) spectroscopy. Selected litters were also incubated with four contrasting soils. Reducing dietary NPP and using phytase decreased total P in litters by up to 38%. Water‐soluble phosphorus (WSP) in litters was decreased 21 to 44% by feeding NPP closer to animal requirement, but was not affected by phytase addition. Solution 31 P NMR spectroscopy showed that feeding NPP closer to requirement decreased orthophosphate in litters by an average of 38% and that adding phytase to feed did not increase the concentration of orthophosphate in litters. Phytase also decreased phytate P in litters by 25 to 38%, demonstrating that it increases phytate P hydrolysis. Incorporation of litters with soils at the same total P rate increased WSP in soils relative to the control; this increase was correlated to soluble P added with litters at 5 d, but not by 29 d. Changes in soil Mehlich‐3 phosphorus (M3‐P) were related to total P added in litter, rather than soluble P. We conclude that feeding NPP closer to requirement and using feed additives such as phytase decrease total P concentrations in litters, while having little effect on P solubility in litters and amended soils.}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Maguire, RO and Sims, JT and Saylor, WW and Turner, BL and Angel, R and Applegate, TJ}, year={2004}, pages={2306–2316} }