MICRONUTRIENT
STATUS OF MANURE
S. M. Combs, J. B. Peters and Ling S. Zhang
Department of Soil Science
University of
Wisconsin-Madison
Animal feeds are routinely
enriched with supplements to minimize potential for mineral deficiency, enhance
feed efficiency or suppress disease.
Most swine and poultry are housed in confinement without access to soil
or forage that enhances the need for feed additives. Under practical feeding conditions it is usually necessary to
provide supplemental sources of several macrominerals (Ca, P, Na, Cl, K, Mg and
S) and trace minerals (As, Co, Cr, Cu, Fe, I, Mn, Mo, Se, Zn and others) to
meet dietary requirements (NRC for Dairy Cattle, 1988, NRC for Swine, 1998 and
NRC for Poultry, 1994). The effects of
diet on manure composition are much less quantified than the digestibility of
nutrients in feeds.
In addition to the presence of trace elements in
manure from supplementation, manure is increasingly being treated with chemical
additives to control odor, adjust pH, precipitate suspended solids or enhance
biological treatment (Day and Funk, 1998).
Amendments such as alum (Al2(SO4)3) and
Fe salts are used effectively in swine manure systems to precipitate
solids. Poultry producers can choose
from several amendments (alum, phosphoric acid, TSP, lime, gypsum, Fe salts and
others) to minimize NH4 volatilization by altering pH or inhibiting
microbial-aided uric acid decomposition.
Manure used to repeatedly supply major nutrients to
crops has the potential to elevate soil concentrations of these elements. The accumulation of P in excess of crop
needs is a common example. The
objective of this limited study was to determine the major nutrient (N, P, K,
Ca, Mg, Na and S) and trace element (Zn, Cu, Fe, Mn, B, Se, Co, Cr and As)
content of dairy, swine and poultry manure and evaluate potential soil
management impacts. Manure samples
submitted by producers to public soil testing labs in the NCR-13, SERA-6 and
NEC-67 regions were split and analyzed by the UW Soil and Plant Analysis
Lab-Madison.
Elemental Composition – ‘as is’
Average
concentrations and associated statistics for 87 dairy, 10 swine and 24 poultry
manure samples are given on an ‘as is’ or wet basis in Table 1. Knowing the ‘as is’ trace element
concentration in manure may be more practical when considering the quantity
potentially spread. Swine and poultry
manure contained similar amounts of Zn, Cu and Mn (0.5–1.1 lb/wet ton) and was
approximately 10-100 times higher than determined in dairy manure (0.01–0.06
lbs/wet ton). Liquid swine manure had
about 6 times (0.6 lbs/1000 gal) as much Cu and about 10 times more Zn (1.03
lbs/1000 gal) than liquid dairy manure.
Total Fe and Al content of swine (especially solid) ranged up to 40
times (19 lbs Fe/wet ton) more than either dairy or poultry.
Swine and poultry manure also contained about 10
times more Se (0.002 lbs/wet ton) than dairy.
Liquid dairy manure has only 0.008 lbs Se/1000 gal Monogastic animals
(poultry, swine) excrete Se primarily in urine but ingested Se is excreted
mainly in feces of ruminants (dairy cattle) (Mayland, 1989).
Swine and poultry manure had 0.01 to 0.02 lb Cr/l000
gal while liquid dairy had 10 times less.
Less than 3% of ingested Cr is actually absorbed by swine (NRC for
Swine, 1998). Similar differences were noted for Co.
Comparisons
Table 2 compares the results of this study on a dry
weight basis to other estimates of elemental concentrations in manure and
sewage sludge, (Capar et al., 1978; Peterson and Kelling, 1987; Dick and Chen,
1997). Changes in specialized feeding practices (i.e. Se, As), greater
therapeutic use of trace elements (i.e. Cu, Zn) and management (litter, no
litter) have contributed to changes in manure composition. This study showed about the same Zn and
slightly higher Cu concentrations than reported by Peterson and Kelling (1987)
for solid swine manure. Substantially
more B (489 mg/kg dry wt) in solid swine manure was estimated by Peterson and
Kelling (1987) than this study showed (30 mg/kg dry wt). Selenium concentrations in solid dairy
manure were about 2 times (0.58 mg/kg dry wt) higher than reported by Capar et
al. (1978) (0.35 low fiber diet, 0.30 high fiber diet). This difference may show the influence of
recently increased allowable supplemental Se levels (NRC for Dairy Cattle,
1988). Determined Cr concentrations in
solid dairy manure were about 10 times and Co 2 to 3 times less than reported
by Capar et al. (1978).
Most notable differences among reported results were
evident for poultry
(Table
2). Dick and Chen (1997) determined
high levels of Cu (477 mg/kg dry wt) similar to this study (437 mg/kg dry wt)
that were substantially greater than the 20-30 mg Cu/kg dry wt indicated by
others. Similar trends were evident for
Zn, As and Mn. Most poultry producers
are reported to feed an excess of CuSO4 causing a weight gain in
broilers related to possible reductions in pathogens contained in litter
(Moore, 1998).
Comparing the trace element composition of manure to
sewage sludge may put manure concentrations in better perspective (Table
2). Manure and sewage sludge (means
from 16 cities) have similar levels of most macro-elements (P, K, Ca, Mg, Na)
and some trace elements (Mn, Al, As).
However, concentrations of Fe, Co and Se are about 2 times, Zn and Cu
about 4 times and Cr 100 to 200 times greater in sewage sludge than
manure. Recent technology advances in
recovery of trace elements prior to discharge probably has decreased trace
element levels in sewage sludge that is currently land applied.
Table
1. 'As-is' total nutrient and trace
element content in selected dairy, swine and poultry manure.
Total Concentration * (wet weight basis)
N P2O5 K2O Ca Mg S Fe Al Na Zn B Mn Cu Se Co Cr As
Dairy solid lbs/ton wet ton
average 8.4 4.7 2.8 6.2 2.6 0.9 0.5 0.5 0.2 0.03 0.01 0.06 0.01 0.0002 0.0003 0.001 0.0001
sd 1.5 1.5 1.6 6.9 2.6 0.2 0.5 0.5 0.2 0.03 0.00 0.04 0.01 0.0001 0.0003 0.001 0.0001
max 13.5 9.8 10.4 51.8 17.6 1.4 3.1 2.4 1.1 0.17 0.03 0.19 0.08 0.0009 0.0020 0.005 0.0001
min 5.5 2.4 1.2 2.5 0.8 0.6 0.1 0.1 0.1 0.01 0.01 0.02 0.00 0.0001 0.0001 0.0001 0.0005
Swine solid
average 24.0 47.6 29.2 26.5 6.6 5.3 19.0 14.4 6.7 0.79 0.04 1.09 0.50 0.002 0.003 0.010 0.0024
sd 4.2 12.0 5.9 7.1 1.2 1.2 4.1 2.2 1.5 0.21 0.01 0.12 0.18 0.001 0.001 0.002 0.0009
max 27.6 60.2 36.6 33.9 7.5 6.8 23.9 16.3 8.6 1.02 0.05 1.30 0.72 0.003 0.005 0.013 0.0039
min 17.0 31.5 23.2 17.2 4.8 3.9 14.7 11.3 5.3 0.53 0.03 0.99 0.33 0.002 0.002 0.008 0.0016
Poultry all **
average 59.9 55.9 39.2 64.8 7.6 7.5 3.0 2.6 7.8 0.48 0.08 0.61 0.66 0.002 0.003 0.014 0.0330
sd 18.1 17.9 11.2 11.2 1.9 2.3 4.3 3.0 3.0 0.17 0.05 0.27 0.39 0.001 0.001 0.009 0.0510
max 94.8 90.4 55.4 191.9 10.6 10.7 21.8 12.7 12.3 0.83 0.30 1.13 1.34 0.004 0.005 0.033 0.1730
min 22.6 21.6 14.5 23.9 3.7 2.7 0.5 0.4 1.7 0.17 0.02 0.15 0.02 0.001 0.001 0.001 0.0002
Dairy liquid *** lbs/1000 gal
average 27.3 10.5 21.1 15.1 5.3 2.2 0.9 0.7 3.3 0.11 0.03 0.11 0.12 0.0010 0.001 0.002 0.0003
sd 10.3 4.7 10.5 8.8 3.0 1.0 0.7 0.6 1.8 0.06 0.02 0.05 0.24 0.0004 0.001 0.001 0.0003
max 50.2 19.6 39.8 36.8 14.7 3.9 3.4 3.0 7.7 0.23 0.06 0.20 1.19 0.0020 0.004 0.005 0.0010
min 11.1 3.4 6.8 5.2 1.9 0.8 0.2 0.2 0.6 0.02 0.01 0.03 0.01 0.0002 0.0003 0.001 0.0001
Swine liquid *
average 69.4 36.8 25.1 21.8 7.4 5.3 2.5 2.4 4.6 1.03 0.06 0.23 0.62 0.002 0.003 0.026 0.0024
sd 19.1 15.6 12.2 9.9 3.1 1.5 2.8 3.6 1.8 1.30 0.03 0.12 0.55 0.001 0.003 0.016 0.0025
max 95.9 63.3 41.8 35.6 10.7 6.7 7.4 8.7 7.3 3.34 0.09 0.41 1.45 0.004 0.008 0.042 0.0067
min 42.1 25.2 8.3 12.7 4.1 3.9 0.7 0.4 2.4 0.24 0.03 0.10 0.08 0.001 0.001 0.004 0.0004
*
Plant available concentrations depend on animal type, nutrient, application
method and number of years of previous
**
Includes unspecified 'chicken', and 'poultry' manure samples.
***
Liquid manure <15% DM.
Table 3. Amount of trace elements applied annually when
manure is used to
supply 160 lbs N/a*.
|
|
Manure
|
|
|
Dairy
|
Dairy
|
Swine
|
Swine
|
Poultry
|
|
Element
|
Solid
|
Liquid
|
Solid
|
Liquid
|
|
|
|
--------------------------------lbs/a/yr--------------------------------
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Zn
|
2.2
|
2.2
|
17.6
|
7.9
|
2.7
|
|
Cu
|
0.6
|
2.4
|
11.1
|
4.9
|
3.7
|
|
Mn
|
3.9
|
2.2
|
24.2
|
1.8
|
3.4
|
|
Fe
|
32
|
18
|
423
|
20
|
16
|
|
B
|
0.6
|
0.6
|
0.9
|
0.5
|
0.4
|
|
Se
|
0.01
|
0.02
|
0.05
|
0.02
|
0.01
|
|
As
|
0.006
|
0.01
|
0.05
|
0.02
|
0.2
|
|
Co
|
0.02
|
0.02
|
0.07
|
0.02
|
0.01
|
|
Cr
|
0.07
|
0.006
|
0.2
|
0.1
|
0.08
|
|
|
|
|
|
|
|
|
|
--------------------------------lbs/ton--------------------------------
|
|
Total
N
|
8.4
|
27.3
|
24.0
|
69.4
|
57.4
|
|
|
|
|
|
|
|
*Based on N availability from surface applications with no
incorporation
30%
— dairy, swine
50%
— poultry
160 lbs N/a x element
lbs/wet ton = element lbs/a
availability (%) (1bs N/wet ton)
Table 4. Background total soil trace element concentrations compared to
build-up from manure use
and proposed phototoxic threshold levels.*
Background** Manure
Mean Range build-up Proposed
--------------------------------
ppm soil -----------------------------
Zn 34-84 <5-300 15-250 70-400
Cu 14-41 1-300 2-60 60-125
B 20-55 7-150 0.3-0.6 25-100
Se
0.2-1.05 0.005-4.0
2.4 5-10
As
3.6-8.8 <0.1-93 3-25 15-50
Co 1-17 0.4-50 0.3-24 25-50
Cr 20-85 1-1500 5.2-5.5 75-100
*Kabata-Pendias and Pendias, 1984.
**mean and range for U.S. surface soils
Soil Management Impacts
Applying
manure to meet the generally high N requirements of row crops or as pre-plant
to seeding alfalfa to meet rotational K2O needs has the potential to
elevate concentrations of trace elements in soils and plants. Table 3 shows the estimated amount of total
trace element applied to soil when manure is used to supply 160 lbs N/a, a common
N recommendation for med/fine textured, high yield potential Wisconsin
soils. Bouldin and Klausner (1998)
estimated that total soil Cu would increase from 2 to 10 times if swine manure
was used for 10 years to supply corn N needs.
Actual increases in soil concentrations of several trace elements from
repeated manure applications have been reported (Kabata-Pendias and Pendias,
1984; Moore, 1998) (Table 4).
Elevated soil concentrations of trace elements means
there is potential for increased plant uptake.
In some soils and for some crops this effect may be welcome. For several trace elements, the amount
applied in a manure application equivalent to 160 lbs N/a is about the
recommended (4-8 lbs Zn/a as ZnSO4; 8-12 lbs Cu/a as CuSO4;
0.5-1.0 lb B/a; 3-5 lbs Mn/a as MnSO4) broadcast application to
responsive crops and deficient soils (UWEX A2809).
The
potential for increased plant uptake of micronutrients at elevated trace
element concentrations in soil depends on several factors such as soil pH, clay
type/amount, plant sensitivity and constituents found in manure itself. Increased plant availability of trace
elements from manure applications is attributed to the presence of soluble
organics and their ability to complex many trace elements (Moore, 1998). However, the use of some amendments (i.e.
lime, alum, Fe salts, TSP) in manure may actually reduce the level of soluble
organics and/or immobilize trace elements (Moore, 1998). Soil characteristics such as texture and
organic matter can also impact availability. For example, a 90% yield loss in a
‘heavy’ soil resulted when soil As concentration was 1000 ppm but only 100 ppm
soil As caused the same yield loss in a ‘light’ soil (Kabata-Pendias and
Pendias, 1984). Soluble organics and other amendments (lime, alum, Fe, salts,
TSP) can potentially impact trace element availability if the chemical form of
the excreted element is reactive. Unfortunately, selenium is excreted mainly in
the non-reactive elemental form and very little becomes available for plant
uptake (Mayland, 1989), necessitating continued use of supplemental selenium
for animals feed locally grown forage.
These
competing effects on the potential for plant uptake makes it difficult to
identify a soil concentration that may result in desired/needed increases in
plant micronutrient concentration.
Consider the following: some
producers have used the same fields for manure applications for many years;
large confinement systems may rely on excessive application rates because of
limited spreadable acreage; and recent changes in therapeutic use of trace
elements in swine and poultry production has shown significant increases in
dietary use of Zn, Cu and As. Therefore there is potential, especially from
repeated use of swine and poultry manure, to build-up trace element
concentrations in soil. This build-up
may be beneficial for many crops and eliminate the need for a broadcast or band
application. However, for some
sensitive crops there is the potential to build soil concentrations of
micronutrients to undesirably high levels.
Testing soils, and manure may be helpful to evaluate past management
practices on future crop needs.
References
Bouldin, D. R. and S. D. Klausner. 1998.
Managing Nutrients in Manure:
General Principles and Applications to Dairy Manure in New York. In
Animal Waste Utilization: Effective Use
of Manure as a Soil Resource. J. L.
Hatfield and B. A. Stewart (eds). Ann
Arbor Press. 320 p.
Capar, S. G., J. T. Tanner, M. H. Friedman and K. W.
Boyer. 1978. Multi-element analysis of animal feed, animal wastes and sewage
sludge. Environ. Sci. and Tech. 12:
785-790.
Day, D. L. and T. L. Funk. 1998. Processing
Manure: Physical, Chemical and
Biological Treatment. In Animal Waste Utilization: Effective Use of Manure as a Soil Resource. J. L. Hatfield and B. A. Stewart (eds). Ann Arbor Press. 320.
Dick, W. A. and L. Chen.
1997. Chemical characterization
and evaluation of nitrogen release rates from poultry manure. Final Report. The Ohio State University/The Agricultural Research and
Development Center. 34 p.
Kabata-Pendias, A. and H. Pendias. 1984. Trace elements
in soil and plants. CRC Press. 315 p.
Mayland, H. F., L. F. James, K. E. Panter, and J. L.
Sonderegger. 1989. Selenium in Seleniferous Environments. In
Selenium in Agriculture and the Environment.
L. W. Jacobs (ed). SSSA Special Publication No. 23, p. 30.
Moore, P. A.
1998. Best Management Practices
for Poultry Manure Utilization that enhance agricultural productivity and
reduce pollution. In Animal Waste Utilization:
Effective Use of Manure as a Soil Resource. J. L. Hatfield and B. A. Stewart (eds). Ann Arbor Press. 320 p.
Nutrient Requirements of Dairy Cattle. 1988.
National Research Council. Academy Press. Washington D.C.
Nutrient Requirements of Swine. 1998. National Research Council. Academy Press. Washington D.C.
Nutrient Requirements of Poultry. 1994.
National Research Council.
National Academy Press. Washington
D.C.
Peterson, J. B. and K. A. Kelling. 1982.
Manure Nutrient Credit Worksheet.
University of Wisconsin-Extension Publication A3411.
UWEX A2809.
Soil test recommendations for field, vegetable, and fruit crops.
K. A. Kelling, L. G. Bundy, S. M. Combs, and J. B.
Peters.
MANURE SAMPLING RECOMMENDATIONS
The
number of manure samples tested by public and private labs has increased from
approximately 6,220 in 1988 to almost 16,000 in 1996 (Soil, Plant and Animal
Waste Analysis Status Report, 1992-96).
However, the majority of animal producers still do not sample
manure. Reasons for not doing so
include sample heterogeneity and the inherent difficulty of taking a
representative sample. Following the
guidelines below for sampling manure should minimize the sample heterogeneity
problem.
Solid Manure – Dairy, Beef, Swine, Poultry
Obtain a composite sample by
following one of the procedures listed below.
One method of mixing a composite sample is to pile the manure and then
shovel from the outside to the inside of the pile until well mixed. Fill a one-gallon plastic heavy-duty ziplock
bag approximately one-half full with the composite sample, squeeze out excess
air, close and seal. Store sample in
freezer if not delivered to the lab immediately.
Sampling while loading—Take at least
five samples while loading several spreader loads and combine to form one
composite sample. Thoroughly mix the
composite sample and take an approximately one pound subsample using a
one-gallon plastic bag.
Sampling during spreading—Spread tarp
in field and catch the manure from one pass.
Sample from several locations and create a composite sample. Thoroughly mix composite sample together and
take a one-pound subsample using a one-gallon plastic bag.
Sampling daily haul—Place a five-gallon
pail under the barn cleaner 4-5 times while loading a spreader. Thoroughly mix the composite sample together
and take a one-pound subsample using a one-gallon plastic bag. Repeat sampling 2-3 times over a period of
time and test separately to determine variability.
Sampling poultry in-house—Collect ten
samples from throughout the house to the depth the litter will be removed. Samples near feeders and waterers may not be
indicative of the entire house and subsamples taken near here should be
proportionate to their space occupied in the whole house. Mix the samples well in a five-gallon pail
and take a one-pound subsample, place it in a one-gallon ziplock bag.
Sampling stockpiled litter—Take ten
subsamples from different locations around the pile at least 18 inches below
the surface. Mix in a five-gallon pail
and place a one-pound composite sample in a gallon ziplock bag
Liquid Manure – Dairy, Beef, Swine
Obtain a
composite following one of the procedures listed below and mix thoroughly. Using a plunger, an up-and-down action works
well for mixing liquid manure in a five-gallon pail. Fill a one-quart plastic bottle not more than three-quarters full
with the composite sample. Store sample
in freezer if not delivered to the lab immediately.
Sampling from storage—Agitate storage
facility at least 2 to 4 hrs before sampling.
Collect at least five samples from storage facility or during loading
using a five-gallon pail. Place
subsample of the composite sample in a one-quart plastic container.
Sampling during application—Place
buckets around field to catch manure from spreader or irrigation
equipment. Combine and mix samples into
one composite subsample in a one-quart plastic container.
Sample Identification and Delivery
Identify
the sample container with information regarding the farm, animal species and
date. This information should also be
included on the sample information sheet.
The routine manure analysis includes dry matter, available (1st
yr) and total N, P2O5 and K2O content. Micronutrients must be requested in addition
to the routine analysis. Contact the UW
Soil and Plant Analysis Lab-Madison, (608) 262-4364 or UW Soil and Forage Analysis
Lab-Marshfield, (715) 387-2523 for further information and current fees.
Keep all
manure samples frozen until shipped or delivered to a laboratory.
Ship early
in the week (Monday-Wednesday) and avoid holidays and weekends.