Transcript Managing Manure Nutrients for Crop Production

Managing Manure Nutrients for Crop Production
– Using DDGS, an Agronomists Viewpoint.
Joel DeJong
ISU Extension Field Specialist/Crops
September 27, 2006
with thanks to:
Dr. John E. Sawyer
Associate Professor
Soil Fertility Extension Specialist
Manure Management Goals
 Manure
production
 Keep
it on site
 Keep it in storage
 Manure
 Keep
application for crop production
it in the field
 Keep it in the soil
 Keep it off / out of watercourses
 Don’t over-apply / over-load nutrients
 Have a Whole Farm Nutrient Plan
Manure Management Incentives
 Water quality
 Immediate effects
 Long-term --
 Nutrient
nutrient enrichment
value - $
 Natural resource sustainability
 Avoid regulatory process
 Good neighbor
Long-Term Benefits From Agronomic
Application of Manure To Crop Land
 Improved
productivity
 Improved fertility

Essential plant nutrients
 Adds
organic matter
 Stimulates biological activity
 Improves
physical structure
 Infiltration
 Stability
 Water holding
 Bulk
density
capacity
Livestock and the Environment
A Sioux County Project, funded by the Leopold Center
Why this project?
*Better use of manure as a nutrient for crop production.
Purchased N + Manure N = 268#/corn acre.
*1998 Ia. Farm & Rural Life poll - 53% take no credit.
Why?
*What is perceived value of the nutrients?
*We think manure works.
Convince skeptics.
The Sioux County Manure
Management Project

Final Producer Survey done in Fall 2001
(375 responses -289 used manure in past 5 years)
 85% believe manure management is better
now in Sioux County than 5 years ago.
 55% sample manure for nutrient content
 80 respondents indicated they changed their
manure management practices because of this
project!
Project funded by Leopold Center for Sustainable Agriculture
Sioux County Survey - How did crop yield
respond to manure application?
Responded yes or (Responded no) to previous question
about having manure analyzed.
As good as ground that had commercial fertilizer applied
26% (30%)
Better than ground that had commercial fertilizer applied
66% (51%)
Worse than ground that had commercial fertilizer applied
3% (4%)
Don’t know
5%
(12%)
The Whole Farm Nutrient Management
Concept and Challenge
 Nutrient
management is an integrated and
continuous process
 Assess overall nutrient balance of farm
 Nutrient

deficit -- Low Intensity
Plan to maximize manure nutrient utilization
 Near balance

Priority for field-by-field plan
 Imbalance of

-- Medium Intensity
excess manure -- High Intensity
Explore off-farm plan to "get rid of manure"
Nutrients in animal manure should be managed
with the same care as commercial fertilizer

To do so it is necessary to determine:
 The
total amount of nutrients in the manure
 The
availability of the nutrients to the crop
 The
amount of nutrients needed to optimize
crop yields
 That
it is being applied uniformly
How to determine the nutrient content of
animal manure
 The
best method is to have a sample
chemically analyzed.
Chemical analysis:
 Eliminates
the need to make assumptions about
storage and handling losses.
 Requires a representative sample of the manure.
 Requires that you know the volume of manure
you have.
Plant availability of the nutrients
in animal manure
 Animal
manure contains all the nutrients
essential for plant growth.
 The nutrients are present in both organic and
inorganic forms.


The nutrients in inorganic form are readily available.
The nutrients in organic form must be converted into
inorganic form. This conversion, mineralization, is
accomplished by microorganisms that live in all soils.
Availability of nitrogen in animal manure
 Nitrogen
is present in both organic and
inorganic forms in animal manure.


The total amount of N present and the proportion of
organic to inorganic N depends on animal species and
how the manure is handled and stored.
Recent research suggests:



About 35% of the total N in dry cattle and dairy
manure is available to plants the year of application
About 100% of the N in liquid swine manure is
plant-available the year of application.
About 65% of total N in poultry manure is
available the year of application.
Application losses of nitrogen

The two forms of inorganic N in animal
manure are ammonium (NH4+) and urea.

If manure is left on the soil’s surface,
ammonium and urea will form ammonia gas
and be lost to the atmosphere. This process is
called volatilization.

You must make adjustments for volatilization
losses of N.
Use correction factors to account for nitrogen
volatilization during land application of animal
manure
Correction factors to account for N volatilization during
land application of animal manures.
Application Method
Correction Factor
Direct injection
0.98
Bdcst & incorp. w/in 24 hrs
0.95
Bdcst & incorp. after 24 hrs
0.80
Bdsct liquid, no incorp.
0.75
Bdcst dry, no incorp.
0.70
Irrigation, no incorp.
0.60
Source: Iowa Department of Natural Resources
Volatilization example -- solid manure
You have solid manure from a beef operation that
contains 12 lb N, 6 lb P2O5, and 12 lb K2O per ton.
The manure will be broadcast onto the land; it will
not be incorporated.
Correction for field volatilization loss:
12 lb N x 0.7 = 8.4 lb N/acre
The amount of N available the year of application is:
8.4 lb X 0.35 = 2.9 lb N/ton of manure.
Availability of phosphorus in animal manure
 P is
present in both inorganic and organic
forms.
 If
the soil test for P is “high” or “very high”
consider that 100% of the P is available.
 If
the soil test for P is “very low,” “low,” or
“optimum” consider that 60% of the total P
will be available the year of application.
Availability of potassium in animal manure
K
is present in animal manure as the
inorganic ion K+. This is the form of K used
by plants, so assume that 100% of the total
K is available to plants in the year of
application.
Nutrient requirements for crop production
 Manure
application rates can be determined
using either N, P, or K, depending on which
set of regulations you fall under.
N
and P are used most frequently to
determine application rates.
There are two methods for determining N
requirements
 Method
1 for N- for DNR Manure Plans
 Estimate
N needs by multiplying the proven
yield for a given field (or area of a field) by a
factor which represents the crop’s N
requirement and then taking credit for N
from other sources.
N fertilizer = (Proven yield x N factor) - N credits
N requirement example
N supplied by cattle feedlot manure
You have established that you can grow 175 bushels
of corn per acre on a field in north central Iowa.
Last year’s soybean crop yielded 50 bushels/acre.
N fertilizer = (175 x 1.2) - 50 lb N/acre
= 210 - 50 = 160 lb N/acre
Manure rate = 160 lb N/acre  2.9 lb N per ton
= 55 tons/acre
[55 tons x 6 lb P2O5/ton = 330 lb P2O5/acre]
There are two methods for determining N
requirements.
 Method
 This
2 for N
method involves use of the Late Spring
Soil Nitrate test.
 Take a 0- to 12-inch soil sample taken when
corn is 6 to 12 inches tall.
 Have the soil samples analyzed for nitrate-N.
 Use the recommended side dress N rate,
based on a table from ISU.
Nitrogen fertilizer recommendations for manured
soilsa and corn after alfalfa
(from
Grain and
fertilizer
prices
Unfavorable
(1 bu. buys
7 lb. of N
Favorable
(1 bu. buys
15 lb. of N)
a
Blackmer, Voss, and Mallarino, 1997)
Recommended N rate
Excessb
Normal
rainfall
rainfall
- - - - lb N/acre - - - 90
90
0
60
0
0c
0
0
Soil test
nitrate
ppm N
0-10
11-15
16-20
>20
0-10
11-15
16-25
>25
Uniform manure, or 2 of 4 years.
c
Optional 30 lb N/acre.
90
60
0
0
b
May rainfall > 5 in.
90
60
30
0
Nutrient Content of Harvested Crops
lb per Unit of Yield
Crop
Unit
P2O5
K2O
Corn
Bu
0.375
0.30
Corn Silage
Ton
3.50
6.50
Soybean
Bu
0.80
1.50
Alfalfa
Ton
12.50
40.00
Pm-1688 General Guide for Crop Nutrient Recommendations in Iowa
Manure N-P-K Application and
Soybean - Corn Rotation Use Example
Crop Nutrients from Cattle
Feedlot Manure with Rate
Based on Total N Application
Nutrient Removal in Grain Based
on 50 bu/acre Soybean and 175
bu/acre Corn Yields
Manure Application, tons/acre
Nutrient
10
18
55
- - - - - - - - lb/acre - - - - - - - - -
S-C
Soybean
Corn
Rotation
- - - - - - - - lb/acre - - - - - - - -
N
29
52
160
0
160(?)
160
P2O5
60
108
330
40
66
106
K2O
120
216
660
75
40
115
Example manure nutrient values for beef feedlot finishing, confined unit: 12 lb total
N/ton; 6 lb P2O5/ton; 12 lb K2O/ton. N available calculated at 2.9#/ton. About 11 tons
per head per year are produced, according to ISU Publication ICM – 1.
DDGS Additional Concerns

From Table 2, “Use of Distillers Grain in Feedlot Diets”

15% DDGS in diet increases excreted P2O5 by 20%
 25% increases excreted by 40%
 40% increase by 70%

Additional Concern regarding Application
Dry manure spreaders are not calibrated often enough
Dry spreaders aren’t always very uniform in application.
Manure application timing
and nutrient availability




Fall applications allow time for organic portions of the
manure to mineralize.
Fall applications also allow for more potential N loss to
the environment.
Do not apply manure in the fall until the soil
temperature (4” deep in the soil) is 50o F and cooling.
Applying manure to frozen soils increases the potential
for environmental contamination.


N and P movement into surface water can be significant.
Apply only on relatively flat land (slopes of 4 % or less).
My Summary - - IT WORKS!
Economically, it makes sense to use
manure as a crop nutrient.
You have to plan for it.
You have to pay attention to the details
You have to take the time needed to do it
right!!
My Suggestions for Manure Management
 1.
Sample the manure.
 2. Plan for where, how much, and how to
apply it. The biggest step!
 3. Monitor it’s performance during the year
– late spring N tests when in doubt?
 4. Get a “report card” of how you did. Use
the end of season stalk N test.
ANY QUESTIONS?