Paul HARRISON
Ken KOELKEBECK
Department of Animal Sciences, University of Illinois Urbana, IL, U.S.A.
Introduction
The volatilization of ammonia (NH3) from poultry manure has become a major problem not only for the health of the birds and caretakers, but also in the negative perception of the public sector, concerning poultry waste. It has been known for a long time that high levels of atmospheric NH3 can negatively affect poultry performance (Anderson et al., 1964). Numerous studies have demonstrated that high atmospheric NH3 within layer and broiler facilities have been shown to reduce egg production, feed efficiency, and growth (Charles and Payne, 1966; Reece et al., 1980; Deaton et al., 1984). In addition to the negative impact of high NH3 levels in a poultry facility on birds, they cause health concerns for the caretakers in those facilities. High NH3 levels sometimes found in a poultry house have also become a cause of concern for the atmosphere outside the poultry house. Thus, this environmental concern has forced regulatory agencies to enforce a daily limit of 100 lbs. of NH3 released to the atmosphere per house or farm (Concentrated Animal Feeding Operation [CAFO]). Therefore, there is a great need to reduce NH3 volatilization from poultry manure to reduce the possible harmful effects of NH3 on animal and human health, and the environment.
Litter additives such as phosphoric acid (Malone, 1987), proprionic acid (Parkhurst et al., 1974), and ferrous sulfate (Huff et al., 1984) have been used to reduce the volatilization of NH3 from poultry manure. These litter additives act by reducing litter pH, which in turn reduces enzymatic and microbial activity and increases the solubility (binding) of ammonia to water. More recent research has examined the use of minerals to reduce microbial uricase activity of poultry manure which would in turn reduce NH3 volatilization (Kim and Patterson, 2003).
In a more recent study, Patterson et al., 2006 examined the impact of sodium bisulfate (PLT®) on ammonia emissions (AE) from laying hen manure and fly concentrations. In that study, a commercial high-rise hen house was used to evaluate the impact of amending manure with PLT® at two levels for potential merit with regard to manure management, nutrients, ammonia emissions and flies. For 45 days in April-June, 2005, three central rows of manure in a 5-row house were either not amended (Control) or amended with two levels of PLT® at 0.97kg/m (1X) or 1.95kg/m (2X) while mixing with a Compost Cat (Farmer Automatic, Inc.). Composting with the Cat was done in all rows (3 days/wk) and amendments were made 8 times during the 45 day experimental period. Manure density, depth, and row width were determined at 6 locations in each treatment row at the beginning of the study (t=0) and on days 4, 17, 31 and 45, corresponding to t=1, 2, 3, and 4. Manure nutrients, adult flies, pupae, larva and ammonia emissions per 0.215 m2 were also measured using Drager Pac III detectors at t = 1, 2, 3 and 4.
Manure depth and row width increased during the experimental period; however, there were no consistent treatment effects on manure density or architecture. Adult flies and pupae counts in the hen house were reduced in the 1X and 2X treatment rows compared to the control at the end of the study. Pupae counts per 150 g manure were significantly reduced in the 2X PLT® treatment at t=2, 3 and 4; while larva counts were elevated in the 1X treatment at t=2. Manure nutrients were significantly influenced by both PLT® levels resulting in greater concentrations of manure nitrogen, ammonia nitrogen, sulphur, sodium and less P2O5 compared to control manure. Ammonia emission rate (ppm/sec) was significantly reduced by the PLT® 1X treatment at t=3 compared to the control and PLT® 2X level at t=1 and 4 compared to the control. Thus, this study demonstrated that commercial application of PLT® to hen manure reduces ammonia losses, increases manure nitrogen and reduces fly activity.
In the poultry industry, the use of a commercially available, topically applied litter and manure amendment has been used to reduce AE. The product, PLT® has been used with success. Most of the work with PLT® has been application of it to broiler litter. Since, a majority of the poultry in the Midwest are laying hens, it is important to evaluate this product and its' effectiveness on laying hen manure.
Effectiveness of commercial products to reduce NH3 volatilization from poultry manure has been based on gaseous concentration of ammonia (ppm) in and around poultry facilities (field conditions). Field conditions reflect an accurate response to an existing condition. However, these responses can include a multitude of unknown variables that may have little to do with the actual effectiveness of the product used to control manure NH3 volatilization. In our laboratory, we have evaluated other product effectiveness based on mass generation and emission rate of ammonia (i.e., mg/hour, mg/bird/hr, mg/mass of manure/hr, or mg/surface area of manure/hr). Knowledge of NH3 volatilization that is based on the mass generation rate from a comparable manure mass and surface has much more potential for establishing dosage effect and time interval effect of applying litter-manure amendment products.
In our laboratory, three emission calorimeters (EC) have been developed to evaluate mass generation and utilization of gases from materials inside the EC. The EC boxes are constructed from 6.4 mm (1/4") thick plexiglass and are 0.356 m high x 1.07 m long x 0.585 m deep (14" x 42.13" x 23"). Clear plexiglass is used for outside observation of inside materials and to allow light into the calorimeter from the surrounding environmental chamber. The EC and air recirculation systems are completely sealed to maintain the gas balance. Airflow volume through each EC (in and out) is measured and regulated and a solenoid valve switching system diverts the airflow to analyzers for constituent NH3 concentration. Ammonia concentration (ppm) is read directly from analysis reaction tubes and is calibrated against two separate standard gases. Also, prior to each experiment, EC are calibrated by O2 and CO2 gas recovery from burning ethanol and are required to have at least a 95% recovery. Thus, this system can accurately measure NH3 emission from any manure source within the calorimeters.
In the past, we have measured ammonia generation from laying hen manure that was subjected to various treatments such as Micro-Aid® and a liquid aluminium sulfate-based substance (AL+ Clear®). Even though most of the products are used in broiler facilities, all treatments were effective in reducing NH3 generation from laying hen manure. In addition, testing various treatments to reduce AE from laying hen manure, we have also determined AE from composted laying hen manure. Results from these research efforts led us to initiate research that is concerned with the influence of some of the previously tested treatments on AE from composted laying hen manure.
Since many composting processes are managed on the same farm facilities as the animals that generate the manure, the ammonia produced by the compost may be attributed to the total allowable level for the animal production unit. Therefore this research was conducted to evaluate possible methods to reduce ammonia that was generated from an on farm composting system. PLT® was tested at 100% of recommended application level (150 pounds per 1000 square feet of surface [T-1]) and 150% of recommended level (T-2). This work was supported by the Jones-Hamilton Co. with donation of PLT® and funds to do the AE testing.
Methods
Composting laying hen manure was collected at a commercial laying hen farm that housed a total of approximately 1.2 million birds. Manure from the birds was collected onto conveyor belts located beneath the cages and removed from the poultry buildings to collecting areas. Manure from the collecting areas was transported to the on-farm composting facility and started into the composting process on Monday, Wednesday, and Friday of each week. Samples of compost material were collected from the top 1 - 2 feet of the approximately three-foot depth of compost. Samples were collected into 18 new plastic 5-gallon containers (14" H x 11.5" D) and a sealed cover was placed over the containers for transport to the EC's, located in the Environmental Research Laboratory (ERL) at the University of Illinois. Six replicate samples were collected from each of three different areas of the composting process. Material collected from the three composting areas was estimated to have been composting for approximately one day, one week, and three weeks. In each of the three composting areas approximately 55 g of PLT® was evenly distributed over the surface of two of the samples (T-1), another two samples were treated with 83 g of PLT® (T-2), and the remaining two served as untreated controls (zero).
The sealed lids were removed from the 18 collection containers approximately 5 hours after being collected and were maintained at 21°C for the remainder of the experiment. Ammonia emission was determined one day after being collected. Ammonia emission levels were evaluated from a random sampling of compost from each treatment that was collected into pre-weighed plastic tubs (5" H x 7" W x 11" L). Ammonia emissions from all compost treatment samples were determined for a one-hour period in each of the three EC, over approximately five hours. Ammonia emissions were sampled three times at the end of each measurement period. The first ammonia samples were taken after the compost had been equilibrating in the EC for approximately one hour, then at two and three hours after disruption of the compost surface while obtaining the sample (mixing). Mixing and obtaining the emissions samples was accomplished with a hand held feed scoop, which was used to remove a 200 to 600 g sample for the plastic containers.
Daily temperature of the collected compost that was maintained for emission sampling in the controlled environment chamber at the ERL was taken at a depth of approximately six inches in the centre of the 1-ft diameter x 14" deep composting material for a week after collection.
After each daily temperature measurement a lid was placed on the compost container and the compost was mixed by inversion and rolling the container and the lid was again removed. Moisture content and reactivity (pH) of the compost was taken from approximate 10-g samples after one day and one week after collection.
Mean AE were reported as pounds of ammonia per day per ton of compost and expressed as AE throughout this report. The level of inference for difference between various treatments was set at P < 0.05.
Results and discussion
Mean AE was 5.02, 4.89, and 3.68 for the zero, T-1, and T-2 levels of PLT® treatments when evaluated over both one day and one week measurement periods after storage in the 5¬-gallon containers. The significance of these PLT® treatment values was confounded by an extremely high AE (17.03) for the compost samples that had been composted for a week on the farm and maintained in their collection containers at ERL for a week (one-week/one week). This high level was consistent for all PLT® treatments in these one-week/one week samples (Table 1).
Mean AE for the PLT® and time of on farm composting (one-day, one-week, and three¬-weeks) when measured the first day after collection is shown in Figure 1. Since the one-week/one week values were not included in this analysis, main effects of both PLT® and time of composting were different. There was not a difference between T-1 and T-2; however, when PLT® treatments (AE = 1.09) were compared to zero PLT® (AE = 2.10) the values were different. AE measurements after one week of storage at ERL were 3.24, 17.03 and 2.63 for the manure that had been composting on the farm for one day, one week, and three weeks, respectively. PLT® had no effects on AE at the one week of storage measurement period even when the one-week-old compost samples were dropped from the analysis.
Mean pH was affected by PLT® treatments when measured the day after it was applied to the surface of the compost and was 8.07, 7.14, and 5.39 for the zero, T-1, and T-2 levels of PLT® treatments, respectively. The PLT® affects were not present when measured one week after application (mean = 8.09 ± 0.26).
Moisture (30.0 ± 1.0%) and temperature (38.2 ± 0.63°C) were not influenced by PLT® treatment and both moisture and temperature were higher for the compost samples that had been composted for a week on the farm. Mean temperature of the compost decreased from 42.4°C on days two and three to 36.6°C on day seven of storage at ERL.
PLT® treatment differences in AE and pH that were measured the first day after collection of compost led us to compare the hourly response of the compost that had been stored at ERL for three weeks (Figure 2). Since this comparison was not a part of our original experimental design and we were also short on analysis supplies, measurements could not be replicated. Inference from the data is not possible and only indicates that future research could lead to important management applications of AE inhibiting substances.
Summary and implications
These data will be used to establish the beneficial effects of composting to reduce AE from laying hen manure. An obvious benefit from AE inhibiting treatments is demonstrated and an obvious need for more information in relation to application level and frequency of application is needed for proper management. Economic and environmental value of composted manure can also be used for inclusion into models that can be used for business decisions.
The authors wish to thank Dr. Randy Chick and his company, Jones-Hamilton Co., for supplying PLT® and financial support.
References
Anderson, D.P., C.W. Beard, and R.P. Hanson. 1964. The adverse effects of ammonia on chickens including resistance to infection with Newcastle Disease virus. Avian Dis. 8:369-379.
Charles, D.R., and C.G. Payne. 1966. The influence of graded levels of atmospheric ammonia on chickens. 1. Effects on respiration and on the performance of broilers and replacement growing stock. Br. Poult. Sci. 7:177-187.
Deaton, J.W., F.N. Reece, and B.D. Lott. 1984. Effect of atmospheric ammonia on pullets at point of lay. Poult. Sci. 63:384-385.
Huff, W.E., G.W. Malone, and G.W. Chaloupka. 1984. Effect of litter treatment on broiler performance and certain litter quality parameters. Poult. Sci. 63:2167-2171.
Kim, W.K., and P.H. Patterson. 2003. Effect of minerals on activity of microbial uricase to reduce ammonia volatilization in poultry manure. Poult. Sci. 82:223-231.
Malone, G.W. 1987. Chemical litter treatments to control ammonia. Proc. of the 22nd meeting on Poultry Health and Condemnations, Ocean City, MD.
Parkhurst, C.R., P.B. Hamilton, and G.R. Baughman. 1974. The use of fatty acids for the control of microorganisms in pine saw dust litter. Poult. Sci. 53:801-806.
Patterson, P., T. Cravener, C. Myers, G. Martin, and Adrizal. 2006. The impact of sodium bisulfate (PLT®) on hen manure, ammonia emissions and flies. Poult. Sci. 85(Suppl. 1):210. (Abstr.)
Reece, F.N., B.D. Lott, and J.W. Deaton. 1980. Ammonia in the atmosphere during brooding affects performance of broiler chickens. Poult. Sci. 59:486-488.
From Proceedings of the "Midwest Poultry Federation Convention", St. Paul, Minnesota, U.S.A.
