Ammonia-nitrogen (NH3-N) loss from agriculture decreases crop yield potential and environmental quality. Incorporating animal manures by chisel plowing (CP) can reduce NH3 loss but may increase crop residue loss compared to lower disturbance incorporation methods and vertical tillage (VT). Few studies have evaluated VT efficacy for incorporating manure and reducing NH3 concentrations compared to traditional tillage tools, such as CP. Six trials during 2013 to 2016 were conducted to evaluate the impacts of manure incorporation method (CP, VT, or broadcast) and weather conditions at the time of application on NH3-N concentrations at a dairy research farm in central Wisconsin, USA. Passive samplers measured NH3-N concentrations at 30-cm above the ground during the first 0 to 24 and 24 to 48 h post-manure application/incorporation. Average NH3-N concentrations for CP and VT were 44 to 86% of broadcast and similar for most trials, while crop residue coverage for VT was greater than CP (39 and 22% of control plots, respectively). Concentrations of NH3-N were correlated with the amount of plot area covered by manure for the first (r = 0.56, p < 0.0001) and second measurement periods (r = 0.85, p < 0.0001). Results show that VT had comparable NH3-N concentration reductions to CP while conserving more crop residue.

Manure application influences ammonia (NH3) and greenhouse gas emissions; however, few studies have quantified the effects of manure application methods and timing on NH3, nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) fluxes simultaneously. We evaluated surface-applied liquid manure application with disk incorporation versus injection on NH3, N2O, CO2, and CH4 fluxes in central Wisconsin corn silage (Zea mays L.) plots during pre-plant (PP) and sidedress (SD) application windows from 2009 to 2011. Manure treatments were PP injection (PP-Inject) and injection at sidedress time (SD-Inject) to growing corn, along with two incorporation times for PP surface application (within 24 h—PP-1-hr; within 3 days—PP-3-day). Mean NH3 emissions were 95% lower for injected treatments compared to surface application in both years, with larger losses for PP-3-day and SD-Surf. While N2O fluxes were generally low, larger increases after manure application were associated with injection and triggered by soil moisture/temperature changes. Mean CO2 and CH4 were unaffected by manure treatments and influenced more by weather. Overall, injection conserved more available soil N while contributing to modest N2O emission, suggesting manure injection may offer greater agri-environmental benefits on the whole over surface application.

Surface applied liquid dairy manure application (i.e., broadcasting) after alfalfa (Medicago sativa L.) harvest is a common practice. Low disturbance manure incorporation (LDMI) may offer multiple benefits including lower ammonia (NH3), greenhouse gas (GHG) and hydrologic nutrient losses compared to broadcast. However, few studies have simultaneously quantified LDMI impacts on alfalfa yield, NH3 and greenhouse gas (GHG) fluxes. We measured NH3, nitrous oxide (N2O), and methane (CH4) fluxes for liquid dairy manure treatments applied to alfalfa plots for broadcast and LDMI over three seasons (2014 to 2016) in central Wisconsin, USA. There were minor differences in alfalfa yield and nitrogen (N) uptake across treatments and years. Shallow disk injection and aerator/band reduced NH3 loss by 95 and 52% of broadcast, respectively, however both substantially increased N2O fluxes (6 and 4.5 kg ha−1 year−1 versus 3.6 kg ha−1 year−1 for broadcast, respectively). The magnitude and timing of N2O fluxes were related to manure application and precipitation events. Average CH4 fluxes were similar among methods and increased with soil moisture after manure application. Results highlight the importance of quantitatively evaluating agri-environmental tradeoffs of LDMI versus broadcast manure application for dairy farms.

Manure and fertilizer applications contribute to greenhouse gas (GHG) and ammonia (NH3 ) emissions. Losses of NH3 and nitrous oxide (N2 O) are an economic loss of nitrogen (N) to farms, while methane (CH4 ), N2 O, and carbon dioxide (CO2 ) are important GHGs. Few studies have examined the effects of low-disturbance manure incorporation (LDMI) on both NH3 and GHG fluxes. Here, NH3 , N2 O, CH4 , and CO2 fluxes in corn (Zea mays L.)-winter rye (Secale cereale L.) field plots were measured under fall LDMI (aerator/band, coulter injection, strip-till, sweep inject, surface/broadcast application, broadcast-disk) and spring applied urea (134 kg N ha-1 ) treatments from 2013 to 2015 in central Wisconsin. Whereas broadcast lost 35.5% of applied ammonium-N (NH4 -N) as NH3 -N, strip-till inject and coulter inject lost 0.11 and 4.5% of applied NH4 -N as NH3 , respectively. Mean N2 O loss ranged from 2.7 to 3.6% of applied total N for LDMI compared to 4.2% for urea and 2.6% for broadcast. Overall, greater CO2 fluxes for manure treatments contributed to larger cumulative GHG fluxes compared to fertilizer N. There were few significant treatment effects for CH4 (P >0.10), however fluxes were significantly correlated with changes in soil moisture and temperature. Results indicate that LDMI treatments significantly decreased NH3 loss but led to modest increases in N2 O and CO2 fluxes compared to broadcast and broadcast-disk manure incorporation. Tradeoffs between N conservation and versus increased GHG fluxes for LDMI and other methods should be incorporated into nutrient management tools as part of assessing agri-environmental farm impacts. This article is protected by copyright. All rights reserved.

Best management practices (BMPs) can mitigate erosion and nutrient runoff. We evaluated runoff losses for silage corn management systems using paired watershed fields in central Wisconsin. A two-year calibration period of fall-applied liquid dairy manure incorporated with chisel plow tillage (FMT) was followed by a three and a half-year treatment period. During the treatment period FMT was continued on one field, and three different systems on the others: (a) fall-applied manure and chisel tillage plus a vegetative buffer strip (BFMT); (b) a fall rye cover crop with spring manure application and chisel tillage (RSMT), both BMPs; a common system (c) fall manure application with spring chisel tillage (FMST). Year-round runoff monitoring included flow, suspended sediment (SS), total phosphorus (TP), dissolved reactive phosphorus (DRP), ammonium (NH4+-N), nitrate, and total nitrogen (TN). Results showed BFMT reduced runoff SS, TP, and TN concentration and load compared to FMT. The RSMT system reduced concentrations of SS, TP, and TN, but not load because of increased runoff. The FMST practice increased TP, DRP, and NH4+-N loads by 39, 376, and 197%, respectively. While BMPs showed mitigation potential for SS, TN, and TP, none controlled DRP, suggesting additional practices may be needed in manured corn silage fields with high runoff potential.

Tillage incorporation of manure can mitigate nutrient loss but increases erosion potential and damages cover crops. More information on the effects of low-disturbance manure application (LDMA) on corn yield, cover crop establishment, and soil properties is needed to better predict manure management practice trade-offs. Here, corn silage (Zea mays L.) yield, winter rye (Secale cereale L.) establishment, and soil nitrate concentrations were compared for a range of manure application methods, including broadcast incorporation, broadcast/disk, fertilizer N (spring applied at 67, 134, and 202 kg N ha-1 ), and a no-manure control, at the University of Wisconsin's Marshfield Agricultural Research Station from 2012 to 2015. Compared with the control, manure and fertilizer N treatments increased corn yield by an average of 1.1- to 1.6-fold and 1.4- to 1.6-fold, respectively. Of the LDMA treatments (sweep-, strip till-, and coulter-injection; aerator/band; broadcast), corn yield was greatest for sweep injection, which did not differ from the high N fertilizer rate (P < .0001). Corn yield averaged across LDMA treatments did not differ from the 134 or 202 kg N ha-1 yields. Compared with disking, LDMA maintained more crop residue (P < .0001), with levels comparable to the control. Soil nitrate-N at depths of 0-30 and 30-60 cm was influenced by LDMA and fertilizer N; however, leaching to 60-90 cm was comparable among treatments. Results indicate that LDMA with injection conserved more N, caused less damage to winter rye, and had similar yields to fertilizer N treatments with improved soil aggregate stability and higher total carbon content.

Process-based models are increasingly used to study agroecosystem interactions and N2 O emissions from agricultural fields. The widespread use of these models to conduct research and inform policy benefits from periodic model comparisons that assess the state of agroecosystem modeling and indicate areas for model improvement. This work provides an evaluation of simulated N2 O flux from three process-based models: DayCent, DNDC, and EPIC. The models were calibrated and validated using data collected from two research sites over five years that represent cropping systems and nitrogen fertilizer management strategies common to dairy cropping systems. We also evaluated the use of a multi-model ensemble strategy, which inconsistently outperformed individual model estimations. Regression analysis indicated a cross-model bias to underestimate high magnitude daily and cumulative N2 O flux. Model estimations of observed soil temperature and water content did not sufficiently explain model underestimations, and we found significant variation in model estimates of heterotrophic respiration, denitrification, soil NH4+ , and soil NO3- , which may indicate that additional types of observed data are required to evaluate model performance and possible biases. Our results suggest a bias in the model estimation of N2 O flux from agroecosystems that limits the extension of models beyond calibration and as instruments of policy development. This highlights a growing need for the modeling and measurement communities to collaborate in the collection and analysis of the data necessary to improve models and coordinate future development.

Agricultural phosphorus (P) management is a research and policy issue due to P loss from fields and water quality degradation. Better information is needed on the risk of P loss from dairy manure applied in winter or when runoff is imminent. We used the SurPhos computer model and 108 site-years of weather and runoff data to assess the impact of these two practices on dissolved P loss. Model results showed that winter manure application can increase P loss by 2.5 to 3.6 times compared with non-winter applications, with the amount increasing as the average runoff from a field increases. Increased P loss is true for manure applied any time from late November through early March, with a maximum P loss from application in late January and early February. Shifting manure application to fields with less runoff can reduce P loss by 3.4 to 7.5 times. Delaying manure application when runoff is imminent can reduce P loss any time of the year, and sometimes quite significantly, but the number of times that application delays will reduce P loss is limited to only 3 to 9% of possible spreading days, and average P loss may be reduced by only 15% for winter-applied manure and 6% for non-winter-applied manure. Overall, long-term strategies of shifting manure applications to low runoff seasons and fields can potentially reduce dissolved P loss in runoff much more compared with near-term, tactical application decisions of avoiding manure application when runoff is imminent.

The objective of this study was to compare different bedding systems for lactating cows in freestall housing. Bedding systems included new sand (NS), recycled byproducts of manure separation (organic solids [OS] and recycled sand [RS]), and foam-core mattresses with a shallow layer of OS (MS). The experimental barn contained 128 freestalls that were divided into 4 equal quadrants with 1 bedding system for each quadrant. All animals included in this study were first lactation cows, randomly assigned to different quadrants as cows calved. This experiment was conducted between January 2014 and December 2015 with 2 periods (1 calendar year for each period). Bedding systems were changed the last week of the first period. Milk yield data was recorded daily and milk samples were collected monthly for milk composition and somatic cell count (SCC). Cow's behavior, hygiene, and hock score were collected monthly. Clinical mastitis and hoof trimming cases were summarized based on veterinary records. Quadrant (pen) was considered the experimental unit with all data averaged by quadrant before analysis. Results represent 2 yr of data collection, and are presented as means ± SD; Therefore, yearly comparisons of means are numerical only, and do not imply statistical significance. The OS and NS groups had greater milk yield compared with RS and MS groups, and the same responses were observed for energy-corrected (ECM) and fat-corrected milk (FCM). The SCC and somatic cell score (SCS) were greatest for the OS group. Cows housed in NS stalls had the greatest cow comfort and stall usage indexes. Cows in OS, NS and RS stalls were cleaner (lower flank score) than cows in MS stall. Cows in MS stalls had the most severe hock lesions (greater hock score). Greater incidence (total cases over 2 yr) of clinical mastitis was observed for cows with OS freestalls. Cows housed in NS and RS stalls needed fewer hoof trimmings than cows housed in OS and MS stalls. Based on the data thus far, NS seems to be the best bedding material for lactating cows based on milk performance, behavior, hygiene, and health data.

Although fall‐grown oat (Avena sativa L.) has potential for use as supplementary fall forage throughout the north‐central United States, one additional benefit is the option for summer manure distribution that is not possible within a conventional corn (Zea mays L.) cropping program. ‘ForagePlus’ oat was seeded into replicated plots fertilized with urea at rates of 0, 20, 40, 60, or 100 kg N ha−1 or with dairy slurry applied at approximately 42,300 and 84,600 L ha−1 (105 and 209 kg N ha−1, respectively). Apparent N recovery from fall‐grown oat plots fertilized with urea ranged from 65.8 to 89.8%. This suggested aggressive scavenging of N, but calculation of these high apparent N recovery rates was dependent on relatively low preplanting soil NO3–N concentrations, as well as a good dry matter (DM) yield response to N fertilization (y = −0.114x2 + 29.9x + 2130; R2 = 0.982). For this study, applications of high and low rates of dairy slurry yielded respective N fertilizer equivalencies of 38 and 45 kg N ha−1 for fall‐grown oat, which are roughly equivalent to Wisconsin recommendations for cereal grains (45 kg N ha−1). Apparent N recovery following application of the high and low rates of dairy slurry was 18.1 and 25.5%, respectively; however, when expressed on the basis of NH4–N applied, apparent N recovery for fall‐grown oat averaged 53.5% and did not differ among slurry application rate treatments. Fall‐grown oat appears to be an effective scavenger of N applied as NH4–N from dairy slurry.Core Ideas Fall‐grown oat possesses unique forage quality characteristics. Fall‐grown oat can serve as attractive emergency fall forage. Use of fall‐grown oat allows for summer manure application that is decoupled from corn production. Fall‐grown oat is an effective scavenger of NH4–N applied from dairy slurry. Fall‐grown oat may be a useful tool in managing N from dairy manures.

Manure applied to cropland is a source of phosphorus (P) and nitrogen (N) in surface runoff and can contribute to impairment of surface waters. Tillage immediately after application incorporates manure into the soil, which may reduce nutrient loss in runoff as well as N loss via NH volatilization. However, tillage also incorporates crop residue, which reduces surface cover and may increase erosion potential. We applied liquid dairy manure in a silage corn ( L.)-cereal rye ( L.) cover crop system in late October using methods designed to incorporate manure with minimal soil and residue disturbance. These include strip-till injection and tine aerator-band manure application, which were compared with standard broadcast application, either incorporated with a disk or left on the surface. Runoff was generated with a portable rainfall simulator (42 mm h for 30 min) three separate times: (i) 2 to 5 d after the October manure application, (ii) in early spring, and (iii) after tillage and planting. In the postmanure application runoff, the highest losses of total P and dissolved reactive P were from surface-applied manure. Dissolved P loss was reduced 98% by strip-till injection; this result was not statistically different from the no-manure control. Reductions from the aerator band method and disk incorporation were 53 and 80%, respectively. Total P losses followed a similar pattern, with 87% reduction from injected manure. Runoff losses of N had generally similar patterns to those of P. Losses of P and N were, in most cases, lower in the spring rain simulations with fewer significant treatment effects. Overall, results show that low-disturbance manure application methods can significantly reduce nutrient runoff losses compared with surface application while maintaining residue cover better than incorporation by tillage.

Corn (Zea mays L.) silage is a productive and popular forage crop that can exacerbate soil loss, surface water runoff, and nonpoint source nutrient pollution from agricultural fields. The objective of this research was to compare soil loss, nutrient runoff, and soil physical properties in conventional monocrop corn silage production to production in Kura clover (Trifolium ambiguum M. Bieb.) living mulch or with a winter rye (Secale cereale L.) cover crop. Five runoff events from simulated rainfall were conducted over a 1‐yr period on loess soils with 8 to 15% slope. Based on weighted averages across all simulations, Kura clover living mulch reduced runoff by 50%, soil loss by 77%, and P and N losses by 80% relative to monocrop corn. Rye planted after corn silage harvest reduced runoff by 67%, soil loss by 81%, P loss by 94%, and N loss by 83%. When rye was planted following corn silage in Kura clover living mulch, runoff was reduced by 68%, soil loss by 77%, P loss by 94%, and N loss by 84% relative to monocrop corn. Greater groundcover in the Kura clover and rye treatments was the primary factor in reducing soil and nutrient losses, but soil aggregate stability and soil disturbance from rye planting were also associated with improved infiltration and reduced runnoff. When grown in Kura clover living mulch, both corn and rye had lower forage yields, a trade‐off with the environmental benefits; but that economic loss would be partially offset by lower fertilizer requirements.Core Ideas Corn silage intercropped with Kura clover reduces soil erosion Winter rye cover crop reduces soil erosion Kura clover increases soil aggregate stability

Infiltration and runoff from manured agricultural fields can result in livestock pathogens reaching groundwater and surface waters. Here, we measured the effectiveness of glass wool filters to simultaneously concentrate enteric viruses and bacteria of bovine origin from water. The recovery efficiencies were determined for bovine viral diarrhea virus types 1 and 2, bovine rotavirus group A, bovine coronavirus, poliovirus Sabin III, toxigenic Escherichia coli ,and Campylobacter jejuni seeded into water with three different turbidity levels (0.5, 215, and 447 NTU). Twenty liters of dechlorinated tap water (pH 7) were seeded with the test organisms, and then passed through a glass wool filter using a peristaltic pump (flow rate = 1 liter min(-1)). Retained organisms were eluted from the filters by passing beef extract-glycine buffer (pH 9.5) in the direction opposite of sample flow. Recovered organisms were enumerated by qPCR except for C. jejuni, which was quantified by culture. Mean recovery efficiencies ranged from 55 to 33% for the bacteria and 58 to 16% for the viruses. Using bootstrapping techniques combined with Analysis of Variance, recovery efficiencies were found to differ among the pathogen types tested at the two lowest turbidity levels; however, for a given pathogen type turbidity did not affect recovery except for C. jejuni. Glass wool filtration is a cost-effective method for concentrating several waterborne pathogens of bovine origin simultaneously, although recovery may be low for some specific taxa such as bovine viral diarrhea virus 1.

Few studies have compared the agronomic performance of cover crop and living mulch systems for no‐till silage corn ( Zea mays L.). In a 4‐yr Wisconsin study, we evaluated soil N levels and forage yields from manured rotations of corn grown with kura clover ( Trifolium ambiguum M. Bieb.) living mulch or interseeded red clover ( T. pratense L.) followed by a year of clover production and from manured continuous corn grown with interseeded Italian ryegrass ( Lolium multiflorum Lam.), fall‐seeded winter rye ( Secale cereale L.), or no companion. Companion crops influenced spring and fall nitrate concentrations near the soil surface but had little effect on total residual fall nitrate to a 1.2‐m depth. Residual nitrate was not related to N balance (inputs minus outputs), but excessive N inputs into corn–clover systems accumulated as organic soil N. Averaged across both phases of the rotation, corn–clover systems provided 0 to 23% less dry matter yield, but 26 to 60% more crude protein yield than continuous corn systems, with corn–red clover often producing the highest silage corn and clover yields. Kura clover provided superior ground cover and nitrate uptake, but it often excessively competed with corn and had low forage yields. Applying fall manure to ryegrass and spring manure to rye maximized silage yields of continuous corn, but manure application time had no other effect on forage yields or on soil N. Overall, no system excelled in all characteristics, thus selection of companion crop and manure management systems for silage corn will depend on feed production and environmental goals.

Application of livestock manure to an annual crop such as corn is typically limited to relatively short periods in the fall after harvest or in the spring before planting. Direct incorporation or injection into a growing corn crop at sidedress time offers another window of time for manure applicationone that avoids planting delays associated with spring application and may reduce potential for nitrate leaching. We established a 2-year field study in northwestern Vermont to compare sidedressed liquid dairy manure directly incorporated with spreader-mounted S-tine cultivators (SD-Incorp) or surface applied (SD-Surf) to preplant-incorporated manure (PP-Incorp) and sidedressed fertilizer N (SD-FertN) to assess effects on corn silage yields, N uptake, and residual soil nitrate. The PP-Incorp manure N rate was higher than SD (212 vs. 150 kg ha(-1)) in Year 1 but similar (270 and 256 kg ha(-1)) in Year 2. In Year 1, N uptake for PP and SD-Incorp was similar and greater than SD-Surf and Control (no manure or additional fertilizer N); corn silage yields showed similar but nonsignificant trends. In Year 2, yield for SD-Incorp was equal to other manure and fertilizer N treatments and greater than Control; effects on N uptake were similar except that PP-Incorp was greater than SD manure. Postharvest residual NO3-N in the 1.2-m soil profile was highest in PP-Incorp and SD-FertN treatments; over-winter decreases in profile NO3-N were greater from SD-FertN than from incorporated manure treatments, suggesting higher leaching or denitrification losses. These results show that sidedressed manure can supply adequate N to meet the needs of a corn silage crop and may reduce excess residual NO3-N and potential for N losses.

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

Manure application to cropland can contribute to runoff losses of P and eutrophication of surface waters. We conducted a series of three rainfall simulation experiments to assess the effects of dairy heifer dietary P, manure application method, application rate, and soil test P on runoff P losses from two successive simulated rainfall events. Bedded manure (18–21% solids) from dairy heifers fed diets with or without supplemental P was applied on a silt loam soil packed into 1‐ by 0.2‐m sheet metal pans. Manure was either surface‐applied or incorporated (Experiment 1) or surface‐applied at two rates (Experiment 2) to supply 26 to 63 kg P ha −1 . Experiment 3 evaluated runoff P from four similar nonmanured soils with average Bray P1‐extractable P levels of 11, 29, 51, and 75 mg kg −1 . We measured runoff quantity, total P (TP), dissolved reactive P (DRP), and total and volatile solids in runoff collected for 30 min after runoff initiation from two simulated rain events (70 mm h −1 ) 3 or 4 d apart. Manure incorporation reduced TP and DRP concentrations and load by 85 to 90% compared with surface application. Doubling the manure rate increased runoff DRP and TP concentrations an average of 36%. In the same experiment, P diet supplementation increased water‐extractable P in manure by 100% and increased runoff DRP concentration threefold. Concentrations of solids, TP, and DRP in runoff from Rain 2 were 25 to 75% lower than from Rain 1 in Experiments 1 and 2. Runoff DRP from nonmanured soils increased quadratically with increasing soil test P. These results show that large reductions in P runoff losses can be achieved by incorporation of manure, avoiding unnecessary diet P supplementation, limiting manure application rate, and managing soils to prevent excessive soil test P levels.

The Wisconsin Phosphorus Index (WPI) is one of several P indices in the United States that use equations to describe actual P loss processes. Although for nutrient management planning the WPI is reported as a dimensionless whole number, it is calculated as average annual dissolved P (DP) and particulate P (PP) mass delivered per unit area. The WPI calculations use soil P concentration, applied manure and fertilizer P, and estimates of average annual erosion and average annual runoff. We compared WPI estimated P losses to annual P loads measured in surface runoff from 86 field-years on crop fields and pastures. As the erosion and runoff generated by the weather in the monitoring years varied substantially from the average annual estimates used in the WPI, the WPI and measured loads were not well correlated. However, when measured runoff and erosion were used in the WPI field loss calculations, the WPI accurately estimated annual total P loads with a Nash-Sutcliffe Model Efficiency (NSE) of 0.87. The DP loss estimates were not as close to measured values (NSE = 0.40) as the PP loss estimates (NSE = 0.89). Some errors in estimating DP losses may be unavoidable due to uncertainties in estimating on-farm manure P application rates. The WPI is sensitive to field management that affects its erosion and runoff estimates. Provided that the WPI methods for estimating average annual erosion and runoff are accurately reflecting the effects of management, the WPI is an accurate field-level assessment tool for managing runoff P losses.

The key first step in evaluating pathogen levels in suspected contaminated water is concentration. Concentration methods tend to be specific for a particular pathogen group, for example US Environmental Protection Agency Method 1623 for Giardia and Cryptosporidium1, which means multiple methods are required if the sampling program is targeting more than one pathogen group. Another drawback of current methods is the equipment can be complicated and expensive, for example the VIRADEL method with the 1MDS cartridge filter for concentrating viruses2. In this article we describe how to construct glass wool filters for concentrating waterborne pathogens. After filter elution, the concentrate is amenable to a second concentration step, such as centrifugation, followed by pathogen detection and enumeration by cultural or molecular methods. The filters have several advantages. Construction is easy and the filters can be built to any size for meeting specific sampling requirements. The filter parts are inexpensive, making it possible to collect a large number of samples without severely impacting a project budget. Large sample volumes (100s to 1,000s L) can be concentrated depending on the rate of clogging from sample turbidity. The filters are highly portable and with minimal equipment, such as a pump and flow meter, they can be implemented in the field for sampling finished drinking water, surface water, groundwater, and agricultural runoff. Lastly, glass wool filtration is effective for concentrating a variety of pathogen types so only one method is necessary. Here we report on filter effectiveness in concentrating waterborne human enterovirus, Salmonella enterica, Cryptosporidium parvum, and avian influenza virus.