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The specialization and intensification of agriculture have produced incredible gains in productivity, quality, and availability of agricultural commodities but have resulted in the separation of crop and animal production. A by-product of this separation has been the accumulation of manure regions where animal production is concentrated. Enter the "manureshed," an organizing framework for integrating animal and crop production where budgeting of manure nutrients is used to strategically guide their recycling and reuse in agricultural production systems where manure resources are of highest value. To move beyond regional nutrient balance analyses into the transformational realm required to mitigate "wicked" manure problems, manureshed management requires recognition of the challenges to systematically reorganizing resource flows. In better integrating crop and livestock systems, manureshed management must account for the unique nature of managing manure nutrients within individual livestock industries, anticipate trade-offs in substituting manure for commercial fertilizer, promote technologies to refine manure, and engage extensive social networks across scales that range from the farmgate to nation and beyond.Manuresheds offer a system-level strategy for recovering manure's fertilizer value. Manuresheds address nutrient imbalances and environmental and socioeconomic outcomes. Manuresheds scale from single operations to a “mega-manureshed” transecting the southeastern United States. Manureshed management supports the strategic alignment of technologies, markets, and networks.

The manureshed represents cropland needed to safely assimilate manure nutrients from an animal feeding operation. Dairy manuresheds can be contained on-farm but may need to involve additional farms that can assimilate excess nutrients. We present case studies reviewing challenges and opportunities to manureshed management in four major dairy-producing states using available information on local manuresheds. Additionally, geographic information system software was used with data from regulated Minnesota dairies to assess cropland assimilative capacities and transport needs surrounding large dairies. Manureshed requirements vary across regions, but increased import of feed and soil phosphorus accumulation constrain on-farm manure utilization across the United States. In Minnesota, a growing proportion of Jersey cattle and differences in continuous corn (Zea mays L.) vs. corn-alfafa (Medicago sativa L.) rotations contribute to the amount of land needed to absorb dairy manure nutrients. Farm-gate budgets reveal that N-based manuresheds can be contained within Idaho dairies, but P-based manuresheds extend beyond the farm. In New Mexico, relocation of surplus manure nutrients off the farm is common via informal networks, but incentives to strengthen these networks could ensure sustainable manureshed management. Evaluation of manureshed requirements in Pennsylvania is often complicated by the need for additional nutrient management planning and greater understanding of nutrient balances on the preponderance of small dairies. Nutrient imbalances with highly concentrated dairy production often lead to the need for manure transport off-farm. However, advances in herd and cropland management offer opportunities to improve on-farm nutrient efficiencies, and emerging networks and technologies promise to facilitate manure export when needed.

Using dairy manure and legumes in crop rotations can reduce inorganic N inputs for corn (Zea mays L.), yet these practices can also contribute to nitrous oxide (N2O) emissions. In two crop rotations we investigated how different (i) organic and inorganic N amendments and (ii) prior legume crops with broadcast manure influenced direct N2O emissions from silt-loam soils planted to no-till corn. We measured N2O fluxes from April to December for two years using closed vented chambers from soils planted to corn with no spring residue to compare inorganic N fertilizer (S-UAN) and two liquid dairy manure application methods: surface broadcasted (S-BM) and injected (S-IM). Emissions were also measured to compare the effect of crop residue of perennial forages, a green manure legume, or soybean (Glycine max L. Merr.) from soils all amended with liquid dairy manure. Nitrous oxide emissions were greatest during the 15–45 days after manure was injected compared to broadcasting, and cumulative N2O emissions were larger from S-IM (2.8–2.5 kg ha−1) than S-BM (1.4–0.7 kg ha−1) and S-UAN (0.3 kg ha−1). Cumulative and yield-scaled N2O emissions did not differ among the prior legume treatments. A ranking approach based on random forests, identified the most important variable contributing to N2O emissions in both comparisons as corn growing degree days, indicative of the asynchrony of spring legume termination and manure application with corn planting and N use; and changing environmental conditions for N mineralization and denitrification.

Understanding the fate of nutrients in land-applied manure is key to improving the efficiency of their use in crop production. We developed nitrogen (N) budgets for 2 years of continuously cropped corn fertilized by dairy manure via broadcast application or shallow disk injection. Major pathways and pools of N loss were monitored on 12, 0.04 ha field lysimeters in central Pennsylvania, USA to estimate the impact of manure application method on N fate: gas emissions, off-site runoff (overland and subsurface flow), crop uptake, and, soil storage. The budgets illuminated trade-offs in N cycling with each management strategy. Crop removal accounted for the largest portions of manure N applied in both budgets (16–43%). Injection manure N balances were more difficult to close because balances included a large proportion of ‘unaccounted’ N (49% and 68% of applied N for two accounting periods). Even so, results point to cumulative differences in nutrient use efficiencies that can be attributed to the greater conservation of ammonia-N with manure injection. There was an apparent build-up of soil N with manure injection that was not observed with broadcast application (in pre sidedress nitrogen test measurements). However, these trends were preliminary; over the two growing seasons covered by this study, these findings did not result in significant differences in corn yield or crop N removal.

Warm season perennial grasses grown for biomass have been suggested as alternative cropping systems on marginal soils to increase farm profit, reduce nitrous oxide (N2O) emissions, and improve water quality. The objectives of this study were to determine: 1) how warm season perennial grasses, switchgrass (Panicum virgatum) and Miscanthus (Miscanthus x giganteus), compare to cool season grasses as streamside buffers on poorly drained marginal soils 2) if inorganic or organic nutrient additions improve biomass yield and affect environmental outcomes? 3) which soil variables influence N2O emissions in situ? We measured soil N2O emissions, soil solution nitrate (NO3−), ammonium (NH4+), O2, moisture, and temperature, along with shallow groundwater NH4+, NO3−, and ortho-phosphate during two growing seasons (2012–2013). N2O emissions were similar across unfertilized warm season grasses and cool season grasses. However, when switchgrass was fertilized with ammonium sulfate or broiler manure, N2O emissions increased significantly. N2O emissions were weakly correlated with soil solution NO3− concentrations and water filled pore space. Shallow groundwater N was elevated under switchgrass fertilized with ammonium sulfate, broiler manure, and when grown with the legume (Desmodium canadense) when compared to unfertilized switchgrass, Miscanthus, and cool season grasses. In 2013 dry aboveground biomass production did not differ among switchgrass treatments which averaged 10 Mg ha. Biomass production was significantly higher for Miscanthus (18.5 Mg ha). The results indicate that unfertilized switchgrass and Miscanthus are as effective as cool season grasses at mitigating N2O emissions and improving water quality, and that Miscanthus has potential production advantages over switchgrass grown on frequently saturated soils.

Nutrient recycling is fundamental to sustainable agricultural systems, but few mechanisms exist to ensure that surplus manure nutrients from animal feeding operations are transported for use on nutrient-deficient croplands. As a result, manure nutrients concentrate in locations where they can threaten environmental health and devalue manure as a fertilizer resource. This study advances the concept of the “manureshed” – the lands surrounding animal feeding operations onto which manure nutrients can be redistributed to meet environmental, production, and economic goals. Manuresheds can be managed at multiple scales, for example, on farms with both animals and crops, among animal farms and crop farms within a county, or even among animal farms and crop farms in distant counties. With a focus on redistribution among counties, we classified the 3109 counties of the contiguous United States by their capacity to either supply manure phosphorus (P) and nitrogen (N) from confined livestock production (“sources”) or to assimilate and remove excess P and N via crops (“sinks”). Manure nutrient source counties were identified in 40 of the 48 states, with a substantial concentration in the southern US. Source counties for manure P greatly outnumbered source counties for manure N (390 vs. 100), and 99 of the 100 manure N source counties were also source counties for manure P. Conversely, sink counties for manure N outnumbered sink counties for manure P (2766 vs. 2317). We used the P balances of the source and sink counties to delineate four manuresheds dominated by various combinations of confined hog, poultry, dairy, and beef industries. The four manuresheds differed in the transport distances needed to assimilate excess manure P from their respective source areas (from 147 ± 51 km for a beef dominated manureshed to 368 ± 140 km for a poultry dominated manureshed), highlighting the need for systems-level strategies to promote manure nutrient recycling that operate across local, county, regional, and national scales.

Managing cropping systems to sequester soil organic C (SOC) improves soil health and resilience to changing climate. Perennial crops, no-till planting, manure, and cover crops can add SOC; however, their impacts have not been well documented in the northeastern United States. Our objectives were (i) to monitor SOC from a bioenergy cropping study in Pennsylvania that included a corn ( L.)-soybean [ (L.) Merr.]-alfalfa ( L.) rotation, switchgrass ( L.), and reed canarygrass ( L.); (ii) to use the CQESTR model to predict SOC sequestration in the bioenergy crops (with and without projected climate change); and (iii) to use CQESTR to simulate influence of tillage, manure, cover cropping, and corn stover removal in typical dairy forage (silage corn-alfalfa) or grain corn-soybean rotations. Over 8 yr, measured SOC increased 0.4, 1.1, and 0.8 Mg C ha yr in the bioenergy rotation, reed canarygrass, and switchgrass, respectively. Simulated and measured data were significantly correlated ( < 0.001) at all depths. Predicted sequestration (8-14 Mg C ha over 40 yr) in dairy forage rotations was much larger than with corn-soybean rotations (-4.0-0.6 Mg C ha over 40 yr), due to multiple years of perennial alfalfa. No-till increased sequestration in the simulated dairy forage rotation and prevented a net loss of C in corn-soybean rotations. Simulations indicated limited impact of cover crops and manure on long-term SOC sequestration. The low solids content of liquid dairy manure is the likely reason for the less-than-expected impact of manure. Overall, simulations suggest that inclusion of alfalfa provides the greatest potential for SOC sequestration with a typical Pennsylvania crop rotation.

Mine-soil treatment using stabilized manure rapidly sequesters large quantities of organic carbon and nutrients. However, the nutrient-rich soil conditions may become highly conducive for production and emission of N2O. We examined this possibility in a Pennsylvania coal mine restored using poultry manure stabilized in two forms: composted (Comp) or mixed with paper mill sludge (Man + PMS) at C/N ratios of 14, 21, and 28 and compared those with the emissions from conventionally treated soil. The mine soil was extremely well drained with 59% coarse fragments. Soil–atmosphere exchange of N2O and CO2 was determined using a sampling campaign of ten measurements between 16 June and 14 September 2009 (90 days) and 13 measurements between 28 June and 9 November 2010 (134 days) using static vented chambers at ambient and increased moisture (water added) content. Potential denitrification was determined in a laboratory incubation experiment. While non-amended mine soil did not have a measurable potential for denitrifying activity, the manure-based amendments introduced the potential. Soil water filled pore space was less than 60% on most sampling days in both ambient and water-added plots. Daily N2O-N emissions ranged between 40 and 70 g N ha−1 with cumulative emissions of 2–4 kg N ha−1 from non-amended, lime and fertilizer (L + F) and Comp, and 3–10 kg N ha−1 from Man + PMS treatments. The maximum emission obtained from Man + PMS represented

Trade-offs associated with surface application or injection of manure pose important environmental and agronomic concerns. Manure injection can conserve nitrogen (N) by decreasing ammonia (NH) volatilization. However, the injection band also creates conditions that potentially favor nitrous oxide (NO) production: an abundant organic substrate-promoting microbial activity, anaerobic conditions favoring denitrification, and large local concentrations of N. We assessed differences in NH volatilization and NO emissions with broadcast application versus shallow disk injection of dairy slurry during the 2011 to 2013 growing seasons on a well-drained silt loam that received average manure-N application rates of 180 kg N ha via injection or 200 kg N ha via broadcast. Ammonia emissions were measured using a photoacoustic gas analyzer and chambers, and NO emissions were measured using syringes to draw timed samples from vented chambers with analysis by gas chromatograph. Results point to a 92 to 98% (3.02-11.05 kg NH-N ha) reduction in NH volatilization (for the initial sampling) with injection compared with broadcasting manure but also reveal 84 to 152% (725.9-3187.8 g NO-N ha) greater cumulative NO emissions. Although losses of N via NO emission were at least three orders of magnitude less than NH volatilization, their potential role as a greenhouse gas is of concern. Despite the potential greenhouse gas trade-offs associated with shallow disk injection of manure, decreasing NH volatilization provides a substantial benefit, especially to farmers who are trying to conserve N and improve the N/P ratio of soil-applied manure.

Mine-land reclamation for biomass production is often achieved by means of large applications of N and organic C with amendments that could create soil conditions favorable for N2O production and emissions. To investigate this possibility, we conducted a laboratory experiment using mine soil collected from an active surface coal mine site near Philipsburg, Pennsylvania. During a 37-d incubation period, we measured N2O and CO2 fluxes from non-amended soil and from soil amended with ammonium nitrate (L + F), composted poultry manure (Comp), poultry manure alone (Man) and mixed with 3 rates of paper mill sludge (PMS) to obtain carbon to nitrogen ratios of 14, 20 and 27 (Man + PMS14, 20 and 27), each at 60% and 80% water filled pore space (WFPS). Results showed that manure alone leads to a greater emission of N2O under laboratory conditions than with L + F. However, composting manure effectively reduced the emissions compared to that of L + F despite a large addition of organic C and N. Composted manure-treated soil emitted less than all other manure-based treatments at both 60% and 80% WFPS. The emissions were greater from soil amended with the Man + PMS treatments compared to non-amended and L + F-amended soil, and it increased during periods of intense microbial activity created by the application of manure and PMS. Higher water content increased emissions particularly during periods of intense microbial activity coupled with inorganic N availability. Cumulative N2O emissions from manure-treated soils represented less than 0·1% loss of total applied N. Copyright © 2014 John Wiley & Sons, Ltd.

This lysimeter experiment was designed to investigate the effects of dietary crude protein (CP) concentration on nitrate-N (NO-N) and ammonia (NH) losses from dairy manure applied to soil and manure N used for plant growth. Lactating dairy cows were fed diets with 16.7% CP (HighCP) or 14.8% CP (LowCP) content. Feces and urine were labeled with N by ruminal pulse-doses of NHCl. Unlabeled and N-labeled feces and urine were used to produce manure for a study with 21 lysimeters in a greenhouse. Manure application rate was 277 kg N ha. Ammonia emissions were measured at 3, 8, 23, 28, 54, and 100 h after manure application. Manure was incorporated into the soil, and a leaching event was simulated. Spring barley was planted (387 plants per m) 7 d after the leaching event and harvested at senescence. Ammonia emission rates and the contribution of urinary N to NO-N were on average about 100% greater for HighCP vs. LowCP manures. With both LowCP and HighCP manures, a greater proportion of urinary vs. fecal N was recovered in leachate NO-N. There was no difference in whole-crop barley N yields between LowCP and HighCP manures, but barley kernel N yield tended to be greater ( = 0.09) for lysimeters treated with HighCP manures. Using a unique labeling approach, this lysimeter experiment demonstrated that when applied at equal soil N application rates, manure from cows fed the HighCP diet resulted in markedly greater NH emissions and urinary N losses with leachate NO-N than manure from cows fed the LowCP diet.

The incorporation of swine manure with tillage effectively reduces ammonia (NH3) emissions and conserves crop available nitrogen (N) but is not compatible with no-till and many other conservation tillage programs. Rolling-tine aerators potentially provide a means to enhance manure infiltration with limited disruption of the soil surface; however, the impact of the range of aerator configurations and manure placements has not been widely studied. We measured NH3 emissions, conducted presidedress nitrate (NO3) tests (PSNT), monitored corn (Zea mays L.) grain yield when swine manure was incorporated with combinations of two aerator toolbar offset angles (0° and 10°) and two manure placements (broadcast before aeration and banded behind aerator), and compared those measurements to unincorporated surface application and an unmanured control. Additional plots were established with five rates of mineral N fertilization to determine N response curve and estimate fertilizer N equivalent of the applied manure. Measurement of cumulative NH3 emissions using a dynamic chamber method showed that offsetting the aerator toolbar by 10° reduced emissions by 65% to 75%, with both manure placements, compared to surface application. However, no consistent reductions in NH3 emissions were observed when the toolbar was not offset. While reduction in NH3 with the offset toolbar could conserve substantial amounts of plant available N, the soil disturbance caused by the offset tines would not be compatible with most conservation tillage programs. Presidedress NO3 test values increased when NH3 emissions were reduced. In 2009, both the angled and straight aerator treatments with manure banded behind the aerator resulted in significantly higher corn grain yield than all other treatments despite reductions in NH3 emissions only when the toolbar was angled. Correlation of yield from manure application treatments with the N response curve for multiple mineral N application rates showed a greater than expected response to manure application. Yield responses are an indication that aeration has benefits in addition to N conservation. We do not recommend the rolling-tine aerator if reducing NH3 emissions in conservation tillage is the primary goal, but future study into other yield-increasing benefits of aeration is needed.

Alternative methods for applying livestock manure to no-till soils involve environmental and economic trade-offs. A process-level farm simulation model (Integrated Farm System Model) was used to evaluate methods for applying liquid dairy (Bos taurus L.) and swine (Sus scrofa L.) manure, including no application, broadcast spreading with and without incorporation by tillage, band application with soil aeration, and shallow disk injection. The model predicted ammonia emissions, nitrate leaching, and phosphorus (P) runoff losses similar to those measured over 4 yr of field trials. Each application method was simulated over 25 yr of weather on three Pennsylvania farms. On a swine and cow-calf beef operation under grass production, shallow disk injection increased profit by $340 yr(-1) while reducing ammonia nitrogen and soluble P losses by 48 and 70%, respectively. On a corn (Zea mays L.)-and-grass-based grazing dairy farm, shallow disk injection reduced ammonia loss by 21% and soluble P loss by 76% with little impact on farm profit. Incorporation by tillage and band application with aeration provided less environmental benefit with a net decrease in farm profit. On a large corn-and-alfalfa (Medicago sativa L.)-based dairy farm where manure nutrients were available in excess of crop needs, incorporation methods were not economically beneficial, but they provided environmental benefits with relatively low annual net costs ($13 to $18 cow). In all farming systems, shallow disk injection provided the greatest environmental benefit at the least cost or greatest profit for the producer. With these results, producers are better informed when selecting manure application equipment.

Injection of cattle and swine slurries can provide soil incorporation in no-till and perennial forage production. Injection is expected to substantially reduce N loss due to ammonia (NH3) volatilization, but a portion of that N conservation may be offset by greater denitrification and leaching losses. This paper reviews our current knowledge of the impacts of subsurface application of cattle and swine slurries on the N balance and outlines areas where a greater understanding is needed. Several publications have shown that liquid manure injection using disk openers, chisels, or tines can be expected to Sreduce NH, emissions by at least 40%, and often by 90% or more, relative to broadcast application. However, the limited number of studies that have also measured denitrification losses have shown that increased denitrification with subsurface application can offset as much as half of the N conserved by reducing NH3 emissions. Because the greenhouse gas nitrous oxide (N2O) is one product of denitrification, the possible increases in N2O emission with injection require further consideration. Subsurface manure application generally does not appear to increase leaching potential when manure is applied at recommended rates. Plant utilization of conserved N was shown in only a portion of the published studies, indicating that further work is needed to better synchronize manure N availability and crop uptake. At this time in the United States, the economic and environmental benefits from reducing losses of N as NH3 are expected to outweigh potential liability from increases in denitrification with subsurface manure application. To fully evaluate the trade-offs among manure application methods, a detailed environmental and agricultural economic assessment is needed to estimate the true costs of potential increases in NO2O emissions with manure injection.

Managing manure in reduced tillage and forage systems presents challenges, as incorporation by tillage is not compatible. Surface-applied manure that is not quickly incorporated into soil provides inefficient delivery of manure nutrients to crops due to environmental losses through ammonia (NH3) volatilization and nutrient losses in runoff, and serves as a major source of nuisance odors. An array of technologies now exist to facilitate the incorporation of liquid manures into soil with restricted or minor soil disturbance, some of which are new: shallow disk injection; chisel injection; aeration infiltration; pressure injection. Surface banding of manure inforages decreases NH3 emissions relative to surface broadcasting, as the canopy can decrease wind speed over the manure, but greater reductions can be achieved with manure injection. Soilaeration is intended to hasten manure infiltration, but its benefits are not consistent and may be related to factors such as soildrainage characteristics. Work remains to be done on refining its method of use and timing relative to manure application, which may improve its effectiveness. Placing manure under the soil surface efficiency by injection offers much promise to improve N use efficiency through less NH3 volatilization, reduced odors and decreased nutrient losses in runoff, relative to surface application. We identified significant gaps in our knowledge as manyof these technologies are relatively new, and this should help target future research efforts including environmental, agronomic, and economic assessments.

Soils with excessive phosphorus (P) levels due to manure application are an environmental concern because water extractable P (WEP) in runoff from these soils can contribute to increased amounts P in surface water, which can contribute to eutrophication of freshwater. Phosphorus based manure management is an option to reduce WEP and thereby reduce agricultural P runoff. In P based manure management, manure is applied to meet the P needs of a crop or not to exceed a given soil test level. Because P base manure management does not supply enough nitrogen (N) to meet the needs of the crop, addition fertilizer N needs to be applied. Fertilizer N applied to soils may increase the rate of mineralization of organic matter and lowers soil pH and therefore may affect the solubility of soil inorganic and organic P pools. The extent to which this may affect WEP or plant P availability is not known. Thus, laboratory and greenhouse studies were conducted to determine the effects of P based manure management on WEP and ...

Although livestock production accounts for a sizeable share of global greenhouse gas emissions, numerous technical options have been identified to mitigate these emissions. In this review, a subset of these options, which have proven to be effective, are discussed. These include measures to reduce CH4 emissions from enteric fermentation by ruminants, the largest single emission source from the global livestock sector, and for reducing CH4 and N2O emissions from manure. A unique feature of this review is the high level of attention given to interactions between mitigation options and productivity. Among the feed supplement options for lowering enteric emissions, dietary lipids, nitrates and ionophores are identified as the most effective. Forage quality, feed processing and precision feeding have the best prospects among the various available feed and feed management measures. With regard to manure, dietary measures that reduce the amount of N excreted (e.g. better matching of dietary protein to animal needs), shift N excretion from urine to faeces (e.g. tannin inclusion at low levels) and reduce the amount of fermentable organic matter excreted are recommended. Among the many 'end-of-pipe' measures available for manure management, approaches that capture and/or process CH4 emissions during storage (e.g. anaerobic digestion, biofiltration, composting), as well as subsurface injection of manure, are among the most encouraging options flagged in this section of the review. The importance of a multiple gas perspective is critical when assessing mitigation potentials, because most of the options reviewed show strong interactions among sources of greenhouse gas (GHG) emissions. The paper reviews current knowledge on potential pollution swapping, whereby the reduction of one GHG or emission source leads to unintended increases in another.

Low-disturbance manure application methods can provide the benefits of manure incorporation, including reducing ammonia (NH3) emissions, in production systems where tillage is not possible. However, incorporation can exacerbate nitrate (NO3⁻) leaching. We sought to assess the trade-offs in NH3 and NO3⁻ losses caused by alternative manure application methods. Dairy slurry (2006-2007) and liquid swine manure (2008-2009) were applied to no-till corn by (i) shallow (

Research from the eastern U.S. indicates that no-till crop production (NT) will typically lead to the sequestration of ~0.5 Mg soil organic C (SOC) ha − 1 yr − 1 for several years after adoption, largely due to a high potential for SOC sequestration near the soil surface. However, the impact of conservation tillage deeper in the soil profile is less clear. Careful consideration of both sampling depth and adequate sample numbers, especially when accessing multiple soil series, is needed in future research to conclusively determine effects that practices have below the upper few cm of soil. While conservation tillage, cover crops, and manure application are generally expected to increase SOC, data are needed for a broader range of practices and soils within the region. Even in cases where no net increase in SOC is achieved, conservation practices are highly valuable for erosion control, enhanced nutrient cycling, and improved water and air quality.

Two experiments were conducted to investigate the effect of dietary crude protein concentration on ammonia (NH(3)) and greenhouse gas (GHG; nitrous oxide, methane, and carbon dioxide) emissions from fresh dairy cow manure incubated in a controlled environment (experiment 1) and from manure-amended soil (experiment 2). Manure was prepared from feces and urine collected from lactating Holstein cows fed diets with 16.7% (DM basis; HCP) or 14.8% CP (LCP). High-CP manure had higher N content and proportion of NH(3)- and urea-N in total manure N than LCP manure (DM basis: 4.4 vs. 2.8% and 51.4 vs. 30.5%, respectively). In experiment 1, NH(3) emitting potential (EP) was greater for HCP compared with LCP manure (9.20 vs. 4.88 mg/m(2) per min, respectively). The 122-h cumulative NH(3) emission tended to be decreased 47% (P=0.09) using LCP compared with HCP manure. The EP and cumulative emissions of GHG were not different between HCP and LCP manure. In experiment 2, urine and feces from cows fed LCP or HCP diets were mixed and immediately applied to lysimeters (61×61×61 cm; Hagerstown silt loam; fine, mixed, mesic Typic Hapludalf) at 277 kg of N/ha application rate. The average NH(3) EP (1.53 vs. 1.03 mg/m(2) per min, respectively) and the area under the EP curve were greater for lysimeters amended with HCP than with LCP manure. The largest difference in the NH(3) EP occurred approximately 24 h after manure application (approximately 3.5 times greater for HCP than LCP manure). The 100-h cumulative NH(3) emission was 98% greater for HCP compared with LCP manure (7,415 vs. 3,745 mg/m(2), respectively). The EP of methane was increased and that of carbon dioxide tended to be increased by LCP compared with HCP manure. The cumulative methane emission was not different between treatments, whereas the cumulative carbon dioxide emission was increased with manure from the LCP diet. Nitrous oxide emissions were low in this experiment and did not differ between treatments. In the conditions of these experiments, fresh manure from dairy cows fed a LCP diet had substantially lower NH(3) EP, compared with manure from cows fed a HCP diet. The LCP manure increased soil methane EP due to a larger mass of manure added to meet plant N requirements compared with HCP manure. These results represent effects of dietary protein on NH(3) and GHG EP of manure in controlled laboratory conditions and do not account for environmental factors affecting gaseous emissions from manure on the farm.

Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic (i.e., corn yield) and environmental (i.e., ammonia volatilization and surface nutrient loss) effects of different poultry litter application methods (surface vs. subsurface) and timings (fall vs. spring) in a potential manure-importing region in the Chesapeake Bay Watershed in the United States. All four litter treatments (205 kg nitrogen ha-1) produced grain yields (10.9–12.8 Mg ha-1) nearly equivalent to or higher than the 11.5 Mg ha-1 yield expected from the same mineral nitrogen rate. Compared with surface application, subsurface application significantly reduced ammonia emission (p < 0.0001), runoff volume (fall: p = 0.02; spring: p = 0.004), and loads of nitrate nitrogen (p < 0.0001; p = 0.003) and dissolved phosphorus (p < 0.0001; p = 0.004) soon after application. Integrating subsurface manure application technologies into the manure redistribution programs would help ensure that the surplus nutrients being relocated provide a maximum agronomic impact and minimum environmental impact to the importing region. J. Liu and D.B. Beegle, Dep. of Plant Science, Pennsylvania State Univ., University Park, PA 16802, USA; P.J.A. Kleinman, C.J. Dell, T.L. Veith, L.S. Saporito, and R.B. Bryant, Pasture Systems and Watershed Management Research Unit, USDA-ARS, University Park, PA 16802, USA; K. Han, State Key Laboratory of Crop Biology, Key Laboratory of Crop Water Physiology and Drought-tolerance Germplasm Improvement, College of Agronomic Sciences, Shandong Agricultural Univ., Tai’an, Shandong 271018, China; D.H. Pote, Dale Bumpers Small Farms Research Center, USDA-ARS, Booneville, AR 72927, USA. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. USDA is an equal opportunity provider and employer. Core Ideas • Manure redistribution adds fertility benefits to recipient fields. • Subsurface application of poultry litter has environmental benefits. • Redistribution plus subsurface application benefits both farmers and the environment. Published February 12, 2016

A dairy farm simulation model was used to compare the environmental and economic impacts of using alternative manure application methods on a dairy farm in Pennsylvania. Model predictions of ammonia emissions, nitrate leaching, and phosphorus runoff were compared to field measurements following no manure application and five application methods. Application methods included broadcast spreading without incorporation, broadcast spreading with immediate incorporation by tillage, band application with aeration, shallow disk injection, and high pressure injection. Following model evaluation, manure application methods were simulated over 25 years of weather on a representative Pennsylvania dairy farm. Immediate incorporation by tillage and the use of the two manure injection techniques reduced ammonia emissions, but nitrate leaching losses were increased. Reductions in ammonia N loss and runoff loss of P were obtained with the use of shallow disk injection without adversely affecting farm profitability.