Raymond C. Ward, Ph.D.
Jolene F. Ward, B.S.
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 greatNew Year !!!
CoRoN As A Replacement for Nitrogen
Reprinted with permission from Dakota Dirt, June 4, 2007
South Dakota State University
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 firstname.lastname@example.org.
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
|Foliar Treatment||Rate/A||140 lbs N/A||175 lbs N/A||200 lbs. N/A||Average|
|F.U rea||8 lb N||191.5||192.9||206.9||197.1|
No Till Fields May Need More Sulfur
By Dr. Ray Ward, Certified Soil Scientist
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
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.
Introducing: Mehlich P-3 Phosphorus Soil Test
This fall Ward Laboratories, Inc. began measuring available soil phosphorus by the Mehlich P-3 extraction method. Soil testing laboratories have been moving toward the Mehlich P-3 including Land Grant University laboratories. Iowa State University's fertilizer recommendation web site evaluates Bray P-1 and Mehlich P-3 exactly the same. This is especially true for Mehlich P-3 analyzed by a colorimetric method. 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.