VOLUME XIX
ISSUE 2
December, 2007
Raymond C. Ward, Ph.D.
President
Jolene F. Ward, B.S.
Corporate Secretary
Carbon Sequestration Paying Dividends
Carbon sequestration is one of
the "hot" topics being discussed in agricultural circles these days.
And, with good reason … carbon sequestration is paying financial and crop
yield dividends.
Organic matter is 58% carbon, which means an increase in organic matter
is necessary for carbon sequestration to occur. To improve the organic
matter concentration in the soil it is almost necessary to leave crop residue
on the soil surface. By tilling the residue into the soil the residue
decomposition is so fast that it does not convert into more organic matter.
Leaving crop residue on the soil surface slows decomposition allowing more
of the carbon in the residue to be retained as part of the soil organic matter.
By leaving the crop residue on the soil surface more water is saved because
it slows evaporation and improves water infiltration, as well.
The interesting fact is that to sequester carbon you must also sequester all
of the plant nutrients found in the crop residue. Besides carbon, other
plant nutrients are also found in crop residue. This means the
organic matter found in the soil contains carbon and most of the other plant
nutrients. The carbon to nitrogen ratio is our grassland soils range from
10 to 12 parts carbon to 1 part nitrogen. And for every 7 to 10 parts
of nitrogen there is one part phosphorus and sulfur. This example is
used to show that carbon sequestration will be better when soil fertility
is adequate for high economic yield.
The Ward family dry land farm in Saline County is in a carbon program.
The family gets a small dividend each year for their continuous no-till practices.
Participating farmers must sign a five-year contract that says they will no-till
for the entire time. The incentive payments must be returned if there
is any deviation from the no-till practice.
Another advantage offered from no-till farming and carbon sequestration is
increased crop yield. Carbon is one of the essential plant nutrients
not talked about because plants get carbon from carbon dioxide that is present
in the atmosphere. If we can keep residue on the surface until the crop
canopy is formed, the residue will decompose during rapid plant growth.
Carbon dioxide is released during residue decomposition, so if more decomposition
occurs during crop growth and after crop canopy, the greater the yield potential.
It has been estimated that 40% of the carbon dioxide used by crops comes
from decomposing organic matter in the soil. The important factor is
to get more carbon dioxide released while the crops are growing.
Best wishes for a great
New Year !!!
CoRoN As A Replacement for Nitrogen
Normally we do not address particular products in this newsletter
but rather address soil fertility principles and research data. However,
numerous questions from across South Dakota this winter and spring related
to the product CoRoN and whether 3 gallons can replace 35 to 40 lbs of nitrogen.
According to the Helena Chemical Company website, CoRoN comes in over 25
different N, P, K grades and micronutrient additions, many of which appear
to target the turf, tree, fruit, and vegetable industry. However many
labels have agriculture crops such as corn, wheat, soybeans, cotton, etc.
on them.
The CoRoN 25-0-0 label indicates the N is derived from urea (18.8%)
methylene diurea and methylene ureas (6.2%). Methylene ureas are
slow release or controlled release N sources. Since this product weighs
9.9 lbs per gallon there is 2.48 lbs total N per gallon of which one quarter
or 0.62 lbs is controlled release. A 3 gallon application will supply
a total of 7.44 lbs total N of which one fourth or 1.86 lbs is controlled
release N.
The CoRoN 25-0-0 label indicates it is recommended for use as a supplement
to a regular fertilizer program only. The general use rate recommendations
label for corn indicates 3-5 gallons per acre of this product (25-0-0) to
be foliar applied at V6-V8 for use as a partial side-dress nitrogen replacement.
The label goes on to state that the maximum replacement value of side-dress
nitrogen (N) using CoRoN 25-0-0 is: 3.0 gal = 37.5 lbs nitrogen (N),
4.0 gal = 50.0 lbs nitrogen (N), and 5.0 gal--64.0 lb N.
The label is not clear, nor do I have an explanation, on how the 7.44 lbs
N applied with the 3 gallons of CoRoN 25-0-0 can replace 37.5 lbs nitrogen
from other sources or where the plant will get the additional 30 lbs of
N if needed.
Several callers indicated the cost of CoRoN was in the range of $6 per gallon.
Although they were not clear on the CoRoN grade, if we assume 25-0-0, the
cost per lb N would be $2.42.
CoRoN is all urea type N, some being slow release, whereas regular UAN (28
or 32-0-0) is only half urea, none of it being slow release. The other
half of UAN is a high salt-index ammonium nitrate. Therefore, CoRoN
will cause less leaf burn with foliar applications. Work done by NDSU
at Minot in 2005 comparing UAN to CoRoN on wheat and Mississippi State University
at the Northeast Branch Experiment Station in 2002 comparing regular urea
to CoRoN on corn show this to be the case.
In a spring wheat trial at Minot, ND, in 2006 CoRoN (28-0-0) applied at
1, 2, or 3 gallons per acre at 5 leaf stage did not increase yield or protein
(Table 2),. All treatments had received preplant N for a 50 bu wheat
yield goal and yields averaged 57 bu per acre. UAN at 5, 10 or 15
gallons per acre had no effect in this trial either. Results were
similar in another trial that included fungicides in both 2005 and 2006.
For more information on these ND trials contact Kent McKay at kent.mckay@ndsu.edu.
Table 2. Helena Spring Wheat Fertility Trial, North Central Research Extension
Center, Minot, ND 2006
All plots received preplant N for 50 bu yield goal
Similar to the spring wheat trials in ND, foliar applications
of 1 or 2 gallons of CoRoN (25-0-0) or urea applied at the V12 growth stage
at Mississippi State University Northeast Branch Experiment Station had
no effect on corn yield (Table 3 adapted for Corn Response to Foliar CORON
Applications with Reduced N Rates, R.R. Dobbs, et.al. Mississippi State
University). For more details on this study see the complete report at http://msucares.com/nmrec/reports/2002/corn/rotation/dobbs01corn3856.pdf.
Prepared by Jim Gerwing
Table 3. Corn Yield Response to CoRoN Foliar Application and N rates on a Leeper Silty Clay Loam Soil, Verona, MS, 2002
--------Yield, Bu/A --------
No Till Fields May Need More Sulfur
Last year we
began making higher sulfur fertilizer recommendations because we found
that no till and reduced tillage slowed mineralization of sulfate from
organic matter. Most sulfates are held in the organic phase of the
soil. When we are no tilling and building organic matter, we get
less release of sulfate from the organic matter. Organic matter
contains the plant nutrients that are present in the crop residue left
on the soil surface. So, as organic matter or carbon © is sequestered
or stored in the soil nitrogen (N), phosphorus (P), sulfur (S), etc are
also sequestered. The C: N: P: S ratio then is
about 100C: 8N: 1P: 1S. The point is that as organic
carbon is increased in the soil, other plant nutrients are also increased
meaning they are not available for crop growth.
We have dropped the amount of sulfur from organic matter factor from our
recommendations, which increases the sulfur recommendation. Other
reasons for more sulfur being recommended is 1) cleaner atmosphere means
there is less sulfur from the air and 2) more pure fertilizers that have
less sulfur are being offered. All of these factors are reasons
for recommending higher sulfur fertilizer to our clients.
To evaluate the level of sulfur in no till fields, soils samples should
be taken at 0-8 inches for all nutrients including sulfate and 8 to 36
inches for nitrate and chloride and in some cases, sulfate.
Applying liquid manure to growing crops has been a convenient and affordable
means of providing a boost to crops during the growing season. University
of Nebraska has researched soluble salts in manure and the salt's impact
on corn and soybeans.
Soluble salts are generally any ion or element that is present in the
liquid. While sodium and chloride are thought of first when it comes
to liquid manure, they actually comprise only a small part. Other
elements present in the liquid manure include ammonium, sulfate, potassium,
calcium, magnesium, chloride, and bicarbonate.
The University of Nebraska Haskell Agriculture laboratory near Concord,
Nebraska has done some research on liquid manure usage. The Haskell
experiments tested applications of different salt concentrations of liquid
manure. They mixed water and liquid manure to make salt concentrations
of 6.l4, 11.7 and 20.3 dS/m (deciSiemens per meter). The study revealed
some leaf burning following applications of liquid manure.
And, while the study revealed the application of liquid manure at 6.14
dS/m created some foliage damage it did not hurt the yield. Higher
rates of liquid manure applied to growing corn or soybeans produced some
decrease in crop yield, however.
Producers using liquid manure on growing plants should also be aware of
weather conditions during the application process. The research
indicated that plant damage is likely caused by absorption into plant
tissue. Therefore, application should be avoided in hot, windy conditions
that create the potential for greater than normal evapotranspiration.
However, we have found that heavily manured soils will have a higher Mehlich P-3 test than the Bray P-1 test. But for soil P tests below 50 ppm P the Mehlich P-3 and Bray P-1 tests are very close to the same number.
Since other laboratories were using Mehlich P-3 we decided to look into the method and found the very close relationship to the Bray P-1 test in most cases. Bray P-1 test does not work well in highly calcareous (excess lime) soils. So, we would measure the excess lime in the soil and then mark those soils for Mehlich P-2 analysis. By adopting Mehlich P-3 we were able to get our P soil tests done more quickly and efficiently. The main difference between Mehlich P-3 and Mehlich P-2 is the soil test laboratories went to Mehlich P-3 instead of Mehlich P-2.
We can still run Bray P-1 if the test is requested. However, we will analyze calcareous soils with the Bray test also. Ward Laboratories thinks the Mehlich P-3 works very well for making phosphate fertilizer recommendations.