Managing Livestock Manure to
Enhance Water Quality and
Social Benefits
Dr. Jeffery Lorimor
Iowa State University
Ames, IA USA
Income from Livestock
 In Romania –
– Rural population is 46% of total
– Overall Ag GDP is 18.5% of total
– Of 14.8 million hectares, 63% is arable
– Meat and egg production has declined
approximately 40% since 1990 except for milk,
even though adequate feed is available
L. Lordache, senior researcher, World Economy Institute
Animal Contributions
 Animals play multiple roles
by providing
– Draft power
– High quality protein
 (meat, milk, eggs)
– Cash income/income
diversification
– Ability to graze non-cropped
ground
– Animal waste products
 Nutrients
 Gas for heating and cooking
IFPRI 2020 Brief no. 61
Livestock Benefit the Poor More
 Livestock benefit the
poor by alleviating
micronutrient
deficiencies and by
directly alleviating
poverty.
 The rural poor tend to
get a higher share of
their income from
livestock than betteroff rural people
Environmental Effects
 The environmental
concerns of increasing
livestock production
are
– Higher concentrations
of animals
– Water quality
deterioration
– Air quality deterioration
Two Environmental Threats
 Two primary threats to water quality may
exist from animal production
– Direct discharge of collected wastes
– Over application of manure nutrients
 Good management can minimize or
eliminate both threats
Direct Discharge Elimination
 Primary concern for direct discharge from
manure to surface waters
– Acute toxicity
 Oxygen demand (COD/BOD)…kills aquatic life
 Ammonia NH3-N
…kills aquatic life
– Chronic effects
 Phosphorus
…excess algae growth
Direct Discharge Elimination
 Primary concern for discharge to ground
waters
– Acute toxicity
 Microorganisms
e coli, streptococcus, etc.
– Might result from poor well construction
 Nitrate
…Blue baby disease
– Might result from too much nitrogen applied to the land
Direct Discharge Elimination
 Solid manure less risky
than liquid manure
– Direct discharges are
less likely since the
manure does not flow
– Adequate space
between the manure
and the water source is
the primary means of
protection
Direct Discharge Elimination
 Most states in the US require separation
distances between livestock production/
manure storage facilities and water
resources
– Iowa, for example, for liquid manure from
animal buildings and manure storages requires
150 -300 meters separation
Direct Discharge Elimination
 Solid manure stacks
– Build stacks on
impermeable floors/soil
– Protect against rainfall
with roofs or covers to
avoid seepage
– Keep stacks away from
streams, rivers, and
lakes
Avoid Over Application of Manure
 Crops need nutrients to produce well
 Nutrients can come from manure, legumes
(N), or from purchased fertilizer
 We know what the crops need
 We know what the animals “produce” in
manure
Clarification
NOTE: animals do not produce nutrients.
They use nutrients. We say they “produce”
because non-grazing animals accumulate
nutrients from feed taken from a large area
into manure that accumulates in a small
area.
Basic Objective
 To avoid water quality problems we need to
redistribute the animal manure back onto
approximately the same area that the animal
feed was produced on.
 Research data tells us that properly
distributed manure nutrients do not cause
water quality deterioration
Properly Managed Manure Will
Reduce Nitrates in Shallow Groundwater
Nitrate Concentrations in Tileline Flow
from
Land Fertilized With Swine Manure
30
25
20
Average
15
10
5
6/
16
/9
4/ 1
21
/9
8/ 2
18
12 /92
/1
5/
9
6/ 2
15
/9
3/ 3
4/
9
5/ 4
27
/9
10 4
/1
/9
2/ 4
1/
9
3/ 5
11
/9
7/ 5
31
/9
2/ 5
8/
9
6/ 6
17
/9
3/ 6
3/
97
0
Nitrates in Tileflow
Poultry Manure Plots
30
Nitrate N, mg/l
25
Field plots
Lysimeters
20
15
10
5
0
Check
1X UAN
1X
2X
Nitrogen Concentrations
90
80
70
Percent
60
50
40
30
20
10
0
Anhydrous
Ammonia
Nitrogen
Urea-Ammonia Liquid Sw ine
Nitrogen
Manure
Bedded Sw ine
Manure
Typical Nutrients Used by Crops
 We know the nutrient needs of the
crops
– Corn needs 55-17-14 kg of N-P-K
– Wheat needs 60-27-14 kg of N-P-K
Yearly Nutrients “Produced”
16
Liquid manure
Kg / animal / year
14
Solid manure
12
10
8
6
4
2
0
N
P
K
Animals per Hectare
to Provide Nitrogen needed
Swine
bedded
Beef
bedded
Poultry
Corn
Wheat
Soybeans
10
11
0 (16)
2
2
0 (6)
500
500
0 (600)
Protecting Water
If we do not apply more nutrients than the
crops need, we will protect water quality.
This applies to both purchased fertilizer and
to animal manure.
To protect water quality…do not over apply
nutrients
Other Issues
 Good manage must include other issues
– Soil erosion…manure can increase of decrease
soil erosion, depending on how it is managed
– Losses…nitrogen losses can occur if manure is
not covered with soil soon after being applied to
the field
– Seepage…seepage from storage piles can be
an issue if left uncontrolled
Summary
 Animals can play a vital role in the well
being of a country
 One of the many contributions animals can
make is to concentrate nutrients from feed
into manure for use as crop fertilizer
 Good manure management is the key to
changing a potential pollutant into a valuable
natural resource
Summary
 The current world bank project near
Calarasi is an excellent example of a
project that can result in improved
manure management and improved water
quality.
 I commend you for your efforts
Annual Nutrient Amounts
 Solid (bedded) beef manure
– 132-66-132 lb/hd/yr (60-30-60 kg/hd/yr)
 Poultry
– 60-60-40 lb/100 birds/yr
(30-30-10 kg/100 birds/yr)
Compost
 Proper compost requires four things:
– Carbon
– Nitrogen
– Oxygen
– Moisture
Composting Principles
Composting Principles
Temperature ºF
Heating
Temperature
plateau
Thermophilic
(conversion)
105
Mesophilic
50
(degradation)
Psychrophilic
(maturation)
Time
Substrate
depletion
Composting Principles
Efficient composting requires
 A balanced source of energy and
nutrients Typically with a C:N ratio
between 20:1and 40:1
 Sufficient moisture
Typically between 40% and 60%
 Sufficient oxygen
Typically 5% or greater
 A pH range between 6 and 8
Composting Principles
Moist, highnitrogen
primary
ingredient
Bulking agent
with
large firm
particles
Dry, highcarbon
amendment
Composting Principles
Composting methods
 Passive composting pile
 Windrow
 Passively aerated windrow
 Aerated static pile
 In-vessel
Composting Principles —
In-Vessel Bin
Composting Principles -Windrows