Effect of Chemical Amendments
on AmmoniaVolatilization
from Poultry Litter
P. A. Moore, Jr.,* T. C. Daniel, D. R. Edwards, and D. M. Miller
ABSTRACT
Ammonia
(NH3)volatilization from poultry litter results in a buildup
of atmospheric NH3in chicken houses, which is detrimental to both
farm laborers and birds. Ammonialoss from litter is detrimental to
the external environment because it results in acid rain, as well as
low N/P ratios in litter, which increase the likelihood of excessive P
runoff into adjacent water bodies. The objectives of this study were
to determine the effect of various chemical amendmentson NH3volatilization and selected litter characteristics after 42 d. Alaboratory study
was conducted using the following amendments: Ca(OH)2 (calcium
hydroxide), A12(SO4)~’lSH20 (alum), alum + CaCO3, FeSO4-7H20
(ferrous sulfate), and MLT(Multi-purpose Litter Treatment, commercial product). Ammonia-freeair was continuously passed through
air-tight chambers containing amendedlitter and any NH3volatilized
fromthe litter was trapped in boric acid solutions, which were titrated
daily for NH~content. The study was carried out for 42 d. At this
time, the litter was analyzed for pH, electrical conductivity (EC),
soluble, organic C (SOC), metals, and soluble and total forms of N
and P. The results of this study indicated that the addition of alum
to poultry litter dramatically reduces NI~ volatilization (up to 99%
less volatilization than controls). Decreases in volatilization resulted
in higher total and soluble N in litter, which increased NIP ratios.
Several of the compoundsstudied (particularly alum) were effective
in decreasing water-soluble P levels in litter. Therefore,we are proposing the use of alum as a litter amendmentin poultry houses.
W
rlTH THE CURRENTSYSTEM used
for poultry production, a beddingmaterial such as wheatstraw, rice
hulls, or woodshavingsis addedto the floor of poultry
houses, and five or six flocks of broilers are grownon
it over a 1-yr cycle. After that time, the litter is removed
andis normallyland-appliedas fertilizer. This re-use of
litter for several flocks results in the productionof NH3
gas, whichcan be producedin high quantities in poultry
houses. For >30 yr, researchers have knownthat NH3
levels build up in poultry-rearing facilities, and this
buildup adversely affects chickens. Scarborough(1957)
and Valentine (1964) both observed NH3levels in the
60 to 70 IxL L-~ range in the atmosphereof poultry
houses. Andersonet al. (1964b)showedthat NH3 levels
reached 100 ~tL L-~ in the atmosphereof commercial
poultry houses. In Europe, COSHH
(Control of Substances Hazardousto Health) has set the limit of human
exposure to NH3at 25 ~tL L-1 for an 8-h day and 35
~tL L-l for a 10-minexposure (Williams, 1992). Reece
et al. (1979)and Andersonet al. (1964a)indicated
high NH3concentrations in poultry houses are more
common
in the winter, since the curtains on the houses
are closed and high ventilation rates increase energy
costs.
Researchon the effects of high NH3levels on poultry
P.A. Moore, Jr., USDA-ARS-PPPSR,
AgronomyDep., Plant Sciences
115, Univ. of Arkansas, Fayetteville, AR72701; T.C. Daniel and D.M.
Miller, AgronomyDep., Univ. of Arkansas; and D.R. Edwards, Agric.
and Biol. Eng. Dep., Univ. of Arkansas. Received18 Apr. 1994. *Corresponding author.
has shownit causes damageto the respiratory tract
(Anderson
et al., 1964a;Nagarajaet al., 1983),increased
susceptibility to Newcastledisease (Andersonet al.,
1964a), increased levels of Mycoplasma
gallisepticum
(Sato et al., 1973), increased incidence of airsaculitis
(Kling and Quarles, 1974; Quarles and Kling, 1974;
Oyetundeet al., 1976), impaired immunosuppression
(Nagaraja et al., 1984), decreased growthrates (Reece
et al., 1980; Charles and Payne, 1966a; Quarles and
King, 1974), decreased egg production (Deatonet al.,
1984;Charles andPayne, 1966b),reducedfeed efficiency
(Cavenyand Quarles, 1978; Cavenyet al., 1981), and
increasedincidenceof keratoconjunctivitis(Bullis et al.,
1950; Faddoul and Ringrose, 1950).
Dueto the reasons listed above, Carlile (1984) indicated that 25 ~tL L-1 NH3should not be exceededin
poultry houses. Attemptsto inhibit NH3volatilization
frompoultry litter werefirst reported in the 1950s(Cotterill and Winter, 1953). Since then, manydifferent
chemicals have been tested for their effectiveness to
inhibit NH3release fromlitter. Carlile (1984)indicated
that these chemicalsfall into two categories, those that
act by inhibiting microbial growth (which wouldslow
uric acid decomposition) and those that combinewith
the released NH3and neutralize it. These chemicals
include calciumchloride (Witter and Kirchmann,1989),
paraformaldehyde
(Seltzer et al., 1969), zeolites like
clinoptilolite (Nakaueet al., 1981), superphosphate
(Cotterill andWinter, 1953; Reeceet al., 1979), phosphoric
acid (Reeceet al., 1979), ferrous sulfate (Huff et al.,
1984), hydratedlime (Cotterill and Winter, 1953), limestone (Cotterill andWinter,1953), gypsum
(Cotterill
Winter, 1953), magnesium
salts (Witter and Kirchmann,
1989), yuccasaponin(Johnstonet al., 1981), acetic acid
(Parkhurst et al., 1974), propionic acid (Parkhurst
al., 1974), and antibiotics (Kitai and Arakawa,1979).
Anotherdetrimental aspect of NH3volatilization from
litter is the effect on acid atmosphericdeposition. ApSimonetal. (1987) indicated that atmosphericNH3pollution plays an importantrole in acid rain. Theyindicated
that the dominantsource of NH3in Europewaslivestock
wastes, with long-term trends showinga 50%increase
in NH3emissions in Europefrom 1950to 1980. Ammonia
raises the pH of rainwater, which allows moreSO2to
dissolve in it. Ammonium
sulfate then forms, which
oxidizes in the soil, releasing nitric and sulfuric acid
(van Breemenet al., 1982). This producestwo to five
times the acid input to soils previously described for
acid atmosphericdeposition, resulting in extremelylow
pHvalues (2.8-3.5) and high levels of dissolved aluminumin noncalcareoussoils (van Breemenet al., 1982,
Abbreviations: MLT,Multi-purpose Litter Treatment; EC, electrical
conductivity; SOC, soluble organic carbon; COSHH,
Control of Substances Hazardousto Health; DRP,dissolved reactive phosphorus; TDP,
total dissolved phosphorus; ICAP, inductively coupled argon plasma;
BOD,biochemical oxygen demand.
Published in J. Environ. Qual. 24:293-300 (1995).
293
294
J. ENVIRON.
QUAL.,VOL.24, MARCH-APRIL
1995
1989). Ammoniavolatilization
can also contribute to
eutrophication. Nitrogen deposited via wet fallout tripled
in Denmark from 1955 to 1980 and corresponded to N
losses from agriculture during this period (Schroder,
1985). The rising levels of N in the fallout were also
shown to be highly correlated to the NO3-Ncontent in
Danish streams (Schroder, 1985).
Another major problem facing the poultry industry is
P runoff from fields receiving poultry litter. Phosphorus
is considered to be the primary element of concern with
respect to eutrophication of freshwater systems (Schindler, 1977). Recent studies have shownextremely high
concentrations in the runoff water from pastures receiving
low to moderate levels of poultry litter (Edwards and
Daniel, 1992a, b, 1993). The majority (80-90%) of
P in the runoff water is dissolved reactive P (Edwards
and Daniel, !993), which is the form that is most readily
available for algal uptake (Sonzogni et al., 1982).
the USA,guidelines for confined animal operations are
currently being formulated by state and federal agencies,
which could limit animal production in certain areas
based on threats to surface and/or groundwater.
In light of these developmentsand the fact that P runoff
fromfields receiving litter is mostlyin the dissolved form,
our laboratory has conducted several experiments to
determine if P solubility in poultry litter can be reduced
with Al, Ca, and/or Fe amendments.These studies have
shownthat water-soluble P concentrations can be reduced
by several orders of magnitude with a variety of amendments (Moore and Miller, 1992, 1994). Although this
wouldbe beneficial from an environmental point of view,
there is little economicincentive (at present) for growers
to decrease P runoff from their land. Therefore, an
attempt was madeto identify secondary benefits of these
litter amendmentsin an effort to maketheir use economically feasible. Since NH3volatilization is such a large
problem in the poultry industry and since this process
is largely dependenton pH(which was found to be greatly
affected by a variety of amendments), this appeared to
be a logical second step. Hence, the objectives of this
study were to determine the effect of various chemical
amendmentson NH3volatilization
and selected litter
characteristics after 42 d.
METHODS AND MATERIALS
Poultry litter was collected from low-ventilation growth
chambersthat had beenused to raise one flock of broilers to
6 wkof age. Thelitter wascollected 2 d after the birds were
removed.Thebeddingof the litter wasrice hulls. Themoisture
content of the litter washigh, due to lowventilation rates in
the chamber,but the litter was not caked. Ninety-twograms
of fresh litter (50 g dry wt. equivalent) was weightedinto
each of 44, 750-mL
air-tight plastic containers. Eleventreatmentswereutilized in this study (Table 1). There werefour
replications per treatment. After weighingthe litter into the
containers, the amendments
were addedand thoroughly mixed
into the litter. Thecontainers were equippedwith air inflows
and outflows. The samples were incubated at 22°C + 3°
and ammonia-freeair (i.e., air that had passed through two
consecutive 1 MHCItraps and one trap containing deionized
water) was continuously passed through each chamberand
any NH3volatilized fromthe litter wastrappedin twoconsecu-
five boric acid traps containing30 mLsolution each. At each
sampling period, the boric acid was removedand replaced
with new acid. The traps were titrated with 0.10 MHCIto
determine the NH3content. Before the study, a preliminary
experiment was conducted in which boric acid traps were
comparedto H2SO,~ traps, whichwere analyzed using normal
Kjeldahl methods.There were no differences from the methods
(data not shown),indicating that the trapping capacity of the
boric acid was not exceededas was experiencedin a study on
NH3volatilization from liquid swine manureconducted by
O’Halloran(1993). Samplesweretitrated daily for the first
d and every other day thereafter. The study was carried out
for 42 d. At this time, a 20-g subsampleof the litter was
extracted with 200mLof deionizedwater for 2 h. The samples
were centrifuged at 6000rpmand aliquots weretaken for pH,
electrical conductivity(EC), alkalinity, NI-h, NO3,dissolved
reactive P (DRP),total dissolved P (TDP),SOC,and metals.
Samplesfor EC, pH, and alkalinity were analyzed immediately in an unfiltered state. Samplesfor NH4and NO3were
filtered through 0.45-~mfilter and frozen. Ammonium
was
determinedwith the salicylate-nitroprusside technique, according to USEPAmethod 351.2 (USEPA,1979). Nitrate
(+ nitrite) was determinedusing the Cd reduction method,
according to Method APHA418-F (APHA,1992). Nitrate
values were very low (<1% of inorganic N) and are not
reported. Metal, DRP,and TDPsamples were filtered (0.45
I~m), acidified to pH 2.0 with HCI, and frozen. Metals and
TDPwere determined by ICAP(inductively coupled argon
plasmaemissionspectrometer). Dissolvedreactive P wasdeterminedusing the ascorbic acid techniquewith an auto-analyzer
according to APHAmethod 424-G (APHA,1992). Soluble
organic C was determined according to APHA
method5310-B
(APHA,
1992).After the waterextract, the litter wasextracted
with 1 MKC1for 2 h for exchangeable
NI-h. After centrifuging,
these sampleswere filtered and analyzed for NIL, as above.
Ten-gramsubsampleswere taken from each container for
water content, total P, and total N analysis. Total N was
determinedby Kjeldahl distillation after using the salicylic
acid modification of the Kjeldahl digestion to include NO3
(Bremnerand Mulvaney,1982) using moist samples (values
were corrected for water content). Moist sampleswere used,
rather than dried, since ovendryingresulted in Nlosses. Total
P was determinedby digesting oven-dried (60°C) litter with
HNO3,
and analyzing the digested sampleusing ICP (Zarcinas
et al., 1987).Fecal coliformcountsweremadeon litter samples
from all the treatments at the end of the study and were
analyzed by the ArkansasWater Resources Laboratory using
the mostprobablenumbermethod.All samplestested negative,
indicatingthat these bacteria do not survivefor longperiods(6
wk) in environmentswith relatively high temperatures(22°C).
Future workwill be conductedto de~erminethe effect of these
amendments
on short-term coliform viability, since bacterial
contaminationof rivers and lakes from manureis an important
water quality problem.
RESULTS
AND DISCUSSION
An average of 14.8 g N kg-1 litter was lost from the
controls (unamendedlitter) during the 42-d incubation
period (Fig. 1). This corresponds to an NH3volatilization
rate of 352 mgN kg-1 d-1. Applications of MLTactually
increased NH3volatilization. The recommendedrate (10
g MLTkg-~) resulted in 31%more N loss via volatilization than the controls (Fig. 1). At two times the recommended rate (20 g MLTkg-~), volatilization
was 15%
higher than the controls (Fig. 1). These results are not
MOOREET AL.:
Table 1. Effect of litter
295
EFFECT OF CHEMICALAMENDMENTS
ON AMMONIAVOLATILIZATION
amendmentson selected litter
characteristics
pH
TKN
Treatment
Control
25 g Ca(OH)2-1
50 g Ca(OH)2-1
-1
100 g AI2(SO4)3"lSH20
200 g A12(SO4)3-18H20
kg-a
100 g Al2(SO4)a-18H204- 50 g CaCO~-1
200 g AI2(SO4)a’18H20+ 50 g CaCOa-t
100 g -~
FeSO4.TI-I20
kg
-m
200 g FeSO4.7H20kg
10 g MLTkg-~
-~
20 g MLTkg
LSD(0.05)
8.89
9.09
9.03
8.37
7.07
8.07
7.88
8.37
8.09
9.11
9.09
0.36
26.1
24.8
26.3
35.7
41.5
29.0
32.6
30.5
37.5
27.0
24.6
2.7
after 42 d.
NH4~
-I
g kg
3.72
3.62
5.80
13.6
17.6
10.9
16.1
12.1
19.9
5.21
3.54
3.16
TP
SOC
DRP
--
24.8
23.3
21.9
22.5
21.6
22.5
21.4
22.3
21.1
24.4
23.5
ns
27.4
26.7
30.3
20.7
22.0
14.8
11.1
19.9
14.6
24.8
26.4
3.5
TDP
mg kg -1 -2022
2621
1305
1798
989
1324
467
734
111
261
431
605
194
286
748
978
529
727
1827
2361
1788
2245
211
295
Sumof water-soluble and exchangeable NI-L-N.
surprising since the pHof MLTis around10. Increases
in litter pHshift the NH3/NH4
equilibrium towardNH3,
resulting in highervolatilization.
Ammoniavolatilization from litter treated with
Ca(OH)2
wasnot significantly different fromthat in the
controls (Fig. 2). Duringthe first 3 d of the experiment,
the rate of NH3loss fromthe 50 g Ca(OH)2
kg- mtreatment
was muchfaster than the controls, probablydue to increases in pH. However, Ca(OH)2was probably converted to CaCO3with time, resulting in lower pHs. The’
pHsof the Ca(OH)2treatments were not significantly
different fromthe controls after 42 d of incubation(Table
1).
Applications of FeSO4" 7H20decreased NH3 volatilization (Fig. 3). CumulativeNH3losses at 42 d were
11 and 58%lower than the controls for the 100 and 200
g FeSOa’7H20
kg-l treatments, respectively. This is
probably due to a decrease in litter pH, since FeS04" 7H20is an acid-forming compound.Although ferrous sulfate controls NH3emissions, there is a major
problemwith its utilization as a litter amendment.
Wallner-Pendletonet al. (1986) reported a large die-off
1-day-oldchicksin a commercial
flock after the litter had
been treated with ferrous sulfate. Apparently,chickens
normally consumea certain amountof the litter and
whenit has beentreated with ferroussulfate, it can result
in increased mortality of the birds.
Alumapplications, both with and without CaCO3,
greatly reduced NH3 volatilization (Fig. 4). Nitrogen
losses at 42 d with alum(at rates of 100and 200 g alum
kg-~), in combinationwith 100 g CaCO3,were 24 and
57%lower than the controls, respectively. Whenalum
was applied alone the Nloss was greatly reduced, with
cumulative NH3losses at Day42 that were 36 and 99%
-~
lowerthan the controls for the 100 and 200 g alumkg
treatment, respectively. In fact, only 0.2 g Nkg-1 was
lost due to NH3volatilization at the high rate of alum
and this occurred in the last weekof the study. Before
that time, NH3 loss from the 200 g alumkg-1 treatment
had been zero.
20
control
10 g MLT/kglitter
¯ 20 g MLT/kg litter
0
Fig. 1. Cumulativeammoniavolatilization
s.41].
l
10
from poultry litter
I
20
Time(days)
I
30
40
with and without MLTamendmentsas a function of time [LSD(O.05) at Day42 =
296
J. ENVIRON.QUAL., VOL. 24, MARCH-APRIL
1995
20
¯
control
/k 25 g Ca(OH~kg
litter
¯ 50 g Ca(OH)2/kglitter
0
20
Time(days)
10
Fig. 2. Cumulativeammoniavolatilization
at Day 42 = 5.41].
frompoultry litter
30
40
with and without calcium hydroxide amendments
as a function of time [LSD(0.05)
In Fig. 5, the total N concentrations of the litter
after 42 d of incubation is plotted as a function of the
cumulativeNH3volatilization for the various treatments.
Treatmentswith higher volatilization had lower total N
concentrations at the end of the study, as would be
expected. Most of the additional N in the treatments
with low volatilization was NH4-N(Table 1). Less than
1%of the inorganic N was present as NO3-N(data not
shown). The total N concentration of the 200 g alum
kg-~ treatment was 41.5 g N kg-1. This was somewhat
-1)
higher than the original N concentration(38.5 g N kg
andsignificantly higher than any of the other treatments.
If the weightof alumpresent had beentaken into account,
the N concentrationsof the litter itself wouldhave been
in excess of 50 g N kg- 1. Highertotal N concentrations
at the end of the studythan the original litter are probably
20 /
~
¯
control
/k
100g ferroussulfate/kglitter
¯
200g ferroussulfate/kglitter
-,,= 15-
0
Fig. 3. Cumulativeammoniavolatilization
Day 42 = 5.41].
10
frompoultry litter
20
Time(days)
30
40
with and without ferrous sulfate amendments
as a function of time [LSD(0.05)
MOOREET AL.; EFFECT OF CHEMICALAMENDMENTS
ON AMMONIAVOLATILIZATION
297
20
~t5
¯
/~
control
¯
200g alum/kglitter
[]
100 g alum/kglitter
100g alurn/kglitter
+ CaCO
a
~
o
._~
0
0
10
0
Fig. 4. Cumulativeammoniavolatilization
at Day42 = 5.41].
20
Time(days)
from poultry litter
30
4O
with and without aluminumsulfate amendments
as a function of time [LSD(0.05)
the result of losses of C via CO2evolution frommicrobial
-~
decomposition. The controls contained 26.1 g N kg
at the conclusion of the study. Therefore, the addition
of alum at the higher rate resulted in a doubling of
the N concentrations in the litter, whichwouldgreatly
increase the value of poultry litter as a fertilizer source.
Research by Mooreet al. (1994, unpublished data)
on the effects of litter amendments
showedthat after 4
wkof growththe cumulative mortality rates of broilers
were significantly lower in alum and ferric chloride
treated litter comparedwith that treated with ferrous
sulfate (3.6, 4.4, 8.3, and 10.2%for the alum, liquid
ferric chloride, control, andferrous sulfate amendments,
respectively). Lowmortality rates in the alumandferric
chloride treatmentcomparedwith the controls were probably due to decreasedlevels of atmosphericNH3,whereas
high mortality in the ferrous sulfate treatmentwasprobably due to Fe toxicity (the rate of Fe applied from the
liquid ferric chloride was muchlower than for ferrous
sulfate). Theseresults supportthe findings of WallnerPendletonet al. (1986) and indicate that ferrous sulfate
is not a suitable amendment
for poultry litter.
45
I
~
.,~-~200 g alum/kglitter
.~. 40
. .:~~.:~..~]..1~
(1~
g..!!(t.~
~.........
contro~
5
10
15
CumulativeAmmonia
koss (g N/kg li~er)
20
298
J. ENVIRON.QUAL., VOL. 24, MARCH-APRIL
1995
The rate of NH3volatilization is highly dependenton
pH. As pH increases, the NH3/NH4
ratio increases,
causing volatilization to increase. Reeceet al. (1979)
indicatedthat NH3volatilizationin poultrylitter increases
dramatically at pHsabove 7. Therefore, acid-forming
compounds,
like alumand ferrous sulfate, reducevolatilization, whereasbasic compoundslike MLT(which has
a pHof 10) increase volatilization. The high rate of
alumresulted in the lowest litter pH(7.07), whichwas
significantly lowerthan the other treatments. This treatmentalso resulted in the lowest alkalinity (data not
shown).
Althoughincreased ventilation will solve mostof the
health problemsassociated with high NH3levels in poultry houses, it is expensiveduring winter months,due to
energy costs. Cart and Nicholson(1980) studied three
ventilation rates (low, medium,and high) and foundthat
weight gains were highest with high ventilation rates.
However,they calculated that the high rate (ventilation
-l)
needed to keep NH3levels below about 40 ~tL L
resulted in an increase in fuel consumptionof 172%
comparedwith the mediumrate (which had ventilation
rates 50%lower). Attar and Brake (1988) developed
computerprogramthat modelledthe economicbenefits
of NH3control in poultry houses. Theycalculated that if
the outside temperatureis 7°C, then the cost of producing
broilers increased by $0.11 kg-mwhenNH3concentrations increased from 25 to 80 ~tL L-~. In a normal
poultry house with 19 000 birds weighing1.82 kg each,
this cost wouldbe roughlyequivalentto $3800per flock.
Thecost of treating the litter with amendments
such as
alumwouldbe almost an order of magnitudelower than
this.
Dissolved reactive P (DRP)concentrations were lowered by all of the treatments studied except MLT(Table
1). DissolvedP concentrations at the end of the study
weresignificantly lowerwith the addition of 200 g alum
kg-1 than any other treatments, either with CaCO3(194
mgP kg-~) or without (111 mg P kg-l). The watersoluble P levels of these treatments were an order of
magnitude lower than the controls (2022 mgP kg-1).
Total dissolved P concentrations were somewhat
higher,
but similar, to DRPlevels (Table 1). Alum,calcium
hydroxide,ferrous chloride, and ferrous sulfate haveall
beenshownto be effective in decreasingP solubility in
poultry litter (Mooreand Miller, 1992, 1994). Since the
major form of P in runoff from fields fertilized with
poultry litter is water-soluble P (Edwardsand Daniel,
1993), P runoff fromfields receivinglitter amended
with
these compounds
should be lower than that from fields
fertilized with normallitter. This was confirmedin a
field study using rainfall simulators by Shreve et al.
(1995), whoshowedthat the P concentrations in runoff
from small plots receiving alum-treated poultry litter
were 87%lower than plots receiving the samerates of
normallitter. Fescue productionwasalso significantly
increased with alum-treated litter comparedwith normal
litter, as a result of increasedNavailability.
Currently,there is concernover P runoff frompastures
receiving poultry litter. Highconcentrationsof soluble
P havebeenobservedfromfields receivingpoultry litter.
The University of ArkansasExtensionService is recommendinggrowersnot apply poultry litter on soils that
test 150 kg P ha-.~ (MehlichIII extractable) or higher
due to the concernover eutrophication. Manyfields in
northwesternArkansasalready test above500 kg P ha-1
and the numberscontinue to grow.This could eventually
force growersto transport litter to areas that test lowin
soil P. Althoughthis will probablyhelp the environment,
it will, in effect, lowerthe value of the litter (due to
high transportation costs). Thegrowers will also have
to buy commercialN fertilizers to meet the N requirementsof their pastures.
Bytreating poultry litter with alum, the amountof P
runoff can be decreaseddramatically. Results fromthis
study also indicate that the use of alumwill benefit
poultry production and the environmentby significantly
reducing NH3volatilization fromlitter. This should not
only help improvebroiler production costs, it will increase the fertilizer valueof the litter by increasingthe
N content. Currently, morethan half of the N in chicken
litter is lost via NH3volatilization beforeit can be taken
up by forages. This results in a poorlybalancedfertilizer
source, since the N/P ratio is low. Forages have much
higher requirements for N than P; therefore, the best
fertilizers shouldreflect this balance. Since alumwould
reducevolatilization losses, the litter wouldbe a higher
quality fertilizer. Thiswill also result in less atmospheric
contamination by NH3.
Anotheraspect of air pollution that will be addressed
by these amendments
is odor. The numberone complaint
received by state and federal environmental agencies
each year against animalproducersinvolves odor. Since
NH3 comprises a portion of the odor associated with
poultry litter, measuresto control odor mustincorporate
strategies that reduceNH3volatilization.
Sincethis workwasinitiated, questionson the environmental impact of these amendmentshave been raised.
For example,will the A1be toxic to grass or fish in
streams receiving runo~ Evidencesuggests no. As mentioned earlier, fescue productionwasfound to be higher
in plots receiving alum-treatedlitter compared
with normal litter (Shreve et al., 1995). Aluminum
represents
one of the primary componentsof soils and sediments.
Its bioavailability is controlled by pH. Aluminum
is not
toxic to plants and fish undernormalpHconditions(i.e.,
whensoil pH is above about 4.5 and water pHis above
pH5.5). In fact, alumis often used in lake restoration
(to precipitate P).
If alumis addedto poultry litter after each flock of
chickens is grown, then the NH3 levels in the houses
will be loweredfor the first fewweeksof the next flock.
Normally,1-day-old chicks, whichare very susceptible
to high NH3are placed in the houses. If the litter has
been treated with alum, then the pHwill start out low
(5-6) andincrease with time as the acidity fromthe alum
reacts with bases, such as NH3. Ultimately, all of the
acidity will be consumed,causing the pHto increase to
over 7 after about 5 wk (Table 1). At such high pHs,
concentrations of A13÷ are too low to cause problems.
Rather, the A1is in the AI(OH)a
form, whichis relatively
insoluble.
MOORE ET AL.: EFFECT OF CHEMICAL AMENDMENTS ON AMMONIA VOLATILIZATION
299
200
y = 5.42x - 9.49
R = 0.79
«
i 150
U)
Jt
^
o
D>
3
100
o
(/)
k
a
15
50
10
15
20
25
30
35
Soluble Organic C (g C/kg litter)
Fig. 6. The relationship between water soluble Cu and soluble organic C in water extracts of poultry litter treated with various compounds.
Moore and Miller (1994) and Shreve et al. (1995)
showed SOC levels decreased dramatically with addition
of various Al and Fe amendments. This was also found
in this study (Table 1). This should help improve the
runoff water from fields receiving poultry litter by decreasing the biochemical oxygen demand (BOD) of the
runoff. Another important parameter that is affected by
SOC is metal solubility. At present, the poultry industry
uses large quantities of heavy metals, such as Cu and
Zn, as feed additives. Since poultry litter contains extremely high concentrations of soluble organics, these
metals become complexed, resulting in unusually high
metal solubilities. Therefore, anything that results in
decreased SOC levels also decreases heavy metal solubility (Fig. 6). Lower SOC and soluble Cu levels were
observed in the alum and ferrous sulfate treatments.
CONCLUSIONS
Results from this study indicated that alum greatly
reduced NH3 volatilization from poultry litter. By decreasing N losses from volatilization, the use of this
compound should result in higher total N concentrations
in poultry litter, thus increasing its value as a fertilizer.
Alum was also shown to decrease the solubility of P in
litter. Since high NH3 levels in poultry houses cause
major economic losses to producers, the use of alum as
a litter amendment should result in increased poultry
productivity, while decreasing the negative environmental impact caused by P runoif from land application of
poultry litter.
ACKNOWLEDGMENTS
The authors gratefully acknowledge funding from USDAARS, Southeastern Poultry & Egg Association, and Arkansas
Water Resources. The authors would also like to acknowledge
the assistance of Suzanne Horlick and Beth Green in sample
preparation and analyses.
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J. ENVIRON. QUAL., VOL. 24, MARCH-APRIL 1995