Manure 101:
Nutrient Management and the
Dairy Industry.
Kevin Erb
UW-Extension NPM Program
University of Wisconsin - Extension
UW-Madison College of Agricultural & Life Sciences
Farmer View of Site-Specific
Future Manure Regulations
What is Nutrient Management?
Common Sense.

Combine on-farm nutrient sources, with
commercial fertilizer, to meet crop need.
On-farm nutrient sources
(manure)
Soil reserves
Commercial fertilizer
Minimize nutrient losses
Environmental Aspects
of Manure

Nutrients
 Nitrogen
 Phosphorus
 Potassium

Bacteria/Pathogens

BOD
Nitrogen

Groundwater Concerns
 EPA
Standard: 10 ppm
 Blue Baby Syndrome

Hypoxia
Hypoxia
Phosphorus

Surface Water Concern

Algae Growth
Environmentalist’s view
of how farmers
manage manure.
Phosphorus

Movement
 Soil
attached is most common route


1 lb P = 500 lb algae
One ton soil eroded = 1 ton algae in water
 Stop
Erosion, Solve Big Part of the
Problem

National Buffer Initiative (USA)
Potassium

Dairy Animal Health Concern
 Too
Much in Ration: Ketosis / Milk Fever
Bacteria

E. Coli
 Up
to 6 month + viable in soil
 Does
not survive as well on surface
 Enters
streams when manure runs off
Antibiotics

Animals DO NOT break them down.
 Excreted
intact with the urine
 Low level resistance concerns
Biochemical Oxygen Demand
* A measure of how much oxygen is
removed from a water body by the
bacteria breaking down organic
materials. (BOD)
Chemical Oxygen Demand (COD)
* Oxygen required to break down
chemical compounds in water body.
Manure Basics

What is Manure?
 Urine,
feces
 Waste
feed
 Parlor
water
 Gray
water (sinks, etc)
Manure Basics

How Much Manure Does a cow
produce in a day? A week? A Month?
A Year?
The Influence Of Milk Production On
Daily Manure Production
Manure (lbs/cow/day)
250
200
150
100
50
0
0
5000
10000
15000
20000
Milk Production (RHA)
25000
30000
How Much Manure?
 Typical
Dairy Cow:
 148
lbs/day (18 gal)
 1036 lbs/week (124 gal)
 4440 lbs/month (531 gal)
 54020 lbs/year (6460 gal)

Does not include youngstock, other wastes
Rule of Thumb #1

One cow plus replacement plus
wastewater = 10,000 gal/year
What is in manure?
 Nutrients
 Nitrogen,
Phosphorus, Potassium
 Micro nutrients (Sulfur, Boron, etc)
 Whatever
the cow eats that does not
become milk or meat becomes
manure.

If it’s in the feed, it’s in the manure.
Dairy Diet and Runoff
Manure from 2 rations applied
 1.28 and 0.48% P (rec is 0.34-0.38)


Runoff was 4x higher for high P diet
 Same

lbs P applied
Runoff was 10x higher when manure
rates were the same.

Ebeling et al, 2001
Dairy Diet Impacts

Ave P in dairy ration is 0.47%

Gunderson, Keuning & Erb, 2001

NRC Recommendation is 0.32-0.38% P

Higher rates are due to belief that lower P
reduces reproductive efficiency.
The Manure Paradox
Crops use N:P:K in a 3:1:2 ratio
Dairy manure is a 1:1:2 ratio (available)
Meet the crop’s N need = excess P
Meet the crop’s P need = buy N fert
Manure Nutrient Content
- Dairy _____________________________________
N
P2O5
K2O
(surface/incorporated)
Solid (lb/ton)
______________________
3/4
3
8
Liquid (lb/1,000 gal)
8 / 10
8
21
_____________________________________
Crop Nutrient Removal
N
P2O5
K2O
- - - - - - - - - lb/a/yr - - - - - - - -
Corn
(160 bu/a)
Corn silage
Soybean
Alfalfa
(23 ton/a)
(40 bu/a)
(5 ton/a)
Reed canarygrass
160*
60
40
225
90
170
115
35
40
250
65
250
250
125
325
(5 ton/a)
*recommended application rate. Note that these numbers vary by state/prov.
Example of
P2O5 Recommendations for Corn
Yield Goal
bu/a
Soil Test Level
Low
Optimum
High
Ex.High
- - - - - - - - - - - - - - lb/acre - - - - - - - - - - - - - -
111-130
131-150
151-170
65
75
80
45
55
60
25
25
30
0
0
0
Corn Nutrient Need vs. Manure Nutrient Supply
Following a Nitrogen Strategy
Manure Application Rates
Nitrogen Strategy
 Maximum rates
 P and K in excess of crop need
 Efficient with time and labor
 Preferred when land is limited
Corn Nutrient Need vs. Manure Nutrient Supply
Following a Phosphorus Strategy
Manure Application Rates
Phosphorus Strategy
 Low rates
 Need supplemental nitrogen
 Increased time and labor
 Need adequate acreage
Manure Nitrogen Content
Total vs. Available
Solid Manure
14
12
lb N/ton 10
8
6
4
2
0
Dairy
Beef
Total N
Swine
Available N
Soil Test P Changes Slowly

Soil buffering capacity
 The
amount of fertilizer needed to change
the soil test level by 1 ppm
 18 lbs P2O5/acre = 1 ppm change in soil P

Time is required to either lower or raise
soil test levels.
Soil Test P Changes Slowly
- Example Soil test P = 75 ppm (EH)
 Track draw-down of P over a
CCOHHH rotation.

Soil Test P Changes Slowly
- Example 


Soil test P = 75 ppm (EH)
Track draw-down of P over a CCOHHH rotation.

Corn @150 bu/a removes 55 lb P2O5/a/yr

Oats @ 100 bu/a removes 25 lb P2O5/a/yr

Alfalfa @ 5 tons/a removes 65 lb P2O5/a/yr
Removal of P2O5 over rotation = 330 lbs P2O5
Soil Test P Changes Slowly
- Example 


Soil test P = 75 ppm (EH)
Track drawdown of P over a CCOHHH rotation.
Removal of P2O5 over rotation = 330 lbs P2O5
Change in soil test P = 330 lb P2O5/18 = 18 ppm P
Soil Test P Changes Slowly
- Example 



Soil test P = 75 ppm (EH)
Track drawdown of P over a CCOHHH rotation.
Removal of P2O5 over rotation = 330 lbs P2O5
Change in soil test P = 330 lb P2O5/18 =
18 ppm P
Soil test P = 57 ppm (EH) after the 6-year rotation.
(75 ppm P - 18 ppm P = 57 ppm P)
Regulations

1972 Clean Water Act

Point vs. Non-Point Sources

Problem Not Yet Solved.
Regulatory Future
Each Providence, State, County,
Township may be different.
 Future

 Lower
AU (animal unit) threshold for permit
 More phosphorus emphasis
 Future emphasis on bacterial / antibiotics /
odor concerns

Short term focus will be on P based nutrient
management
Economics
(Nitrogen @ $0.20/lb)
100 Cow Dairy
Alfalfa N =
$ 1,200
(50 acres/yr @ 120 lbs N/a)
Manure N =
$ 1,320
(22 tons/cow/year @ 3 lbs N/ton)
Total On-Farm N =
$ 2,520
Economics
(P2O5 @ $0.25/lb; K2O @ $0.13/lb)
100 Cow Dairy
Manure P2O5 =
$ 1,650
(22 tons/cow/year @ 3 lbs P2O5/ton)
Manure K2O =
$ 2,288
(22 tons/cow/year @ 8 lbs K2O/ton)
Total Manure P205 & K2O =
$ 3,938
If You Are Going To
Use Manure
as a Fertilizer…
Treat It
Like A
Fertilizer!
Soil Test Phosphorus Variability
from a Wisconsin Dairy Farm
Public Relations

Manure Handling and Application
 Odor
control
 Real or perceived excessive rates
 Road spillage
 Traffic hazards & delays
 Spreading near water
 Cattle in water
Challenges of the Future:

Dairy Trends.
 Management:
More cows, fewer farms.
 Realization by farmers that manure
management requires a cash investment.
 Manure’s Internet IPO: Lots of ideas now,
lots of broken ideas coming in a few
years. Easiest to use / most farmprofitable techniques will remain.
Opportunities of the Future:

Every farm will have a nutrient
management plan.
– Phosphorus Pendulum
 Affiliated and independent consultants
 Site-specific research
 Nitrogen

Between 1992 and 2001, UWGB was the lead
institution for mass balance research.
Farmers are searching for
answers.
Manure is no longer
considered the last item
after everything else is done.
kevin.erb@ces.uwex.edu