Could Sugar Help Drought Stressed Corn?
LEXINGTON, KY.
The dry weather has farmers
looking for any options
to alleviate drought
stress. Some are tempted to
try sugar. Plants make glucose
sugar through the
process of photosynthesis.
Crop scientists estimate that
about 78 pounds of glucose is
needed to produce one bushel of corn and 119
pounds of glucose is needed to produce one
bushel of soybean.
To extend those calculations, 50 bushels of
soybeans require about 5,965 pounds of glucose
and 200 bushels of corn require about
15,580 pounds of glucose. In comparison, some
of the products being sold are putting on 16
fluid ounces of product. Those products contain
34 percent sugar, which comes out to 5.44
ounces of sugar per acre. That is a very small
amount compared to what the crops require.
Some of the products claim activity to boost
micro-organism activity in the soil and that will
help with uptake of nutrients. But, there may
be as much as 2,000 pounds of bacteria per
acre of soil. There are other micro-organisms as
well, including fungi. Is 5.44 ounces of sugar
enough to feed 2,000 pounds of bacteria plus
the fungi and other organisms?
Researchers investigated various forms of
sugar applied at 3 pounds per acre to soybeans
across Minnesota, Wisconsin, Illinois and Indiana.
Some of the sugar sources were applied
two times. No yield increases were observed in
any of those locations.
The cost of some of these foliar products is
also concerning. In one scenario, 16 fluid
ounces is said to cost $6.00/acre. If the equivalent
rate of sugar was applied as corn sugar
purchased in bulk, the cost would be around
$0.24/acre.
Spending $6.00 on 5 ounces of sugar when a
corn crop uses 78 pounds of sugar for each
bushel seems like a long shot for any yield effect.
While drought stress on the crop is extremely
frustrating, and most producers want to try to
do something...sugar most likely is not the answer.
Calculations:
• 1 bu of corn = 56 pounds and 1 bu of soybean
= 60 pounds
• 16 fl oz of a foliar product (34% sugar) equals
5.44 oz of sugar. So $1.10/ fl oz of sugar =
$6.00/acre
• corn sugar or high fructose corn syrup (24%
water + 55% fructose + 42% glucose) costs up to
$700 / Metric Ton in bulk sales, according to
alibaba.com
• 1 metric ton = 1,000 kg ≈ 722 L ≈ 24,413 fl
oz (bulk density of corn sugar 1.384 kg/L)
• So, $700 Metric Ton ≈ $0.03 / fl oz of corn
sugar
• Corn sugar is 76% sugar. If cut in half with
water, the solution is 38% sugar. 8 fl oz/A of
corn sugar (or 16 fl oz of 38% sugar solution) =
$0.24/A (Note: this does not include a shipping
charge and assumes that the cost of water is
zero. If water and shipping doubled the cost of
corn sugar,the bulk corn sugar is still much
cheaper than the foliar product.)
References:
• Connor, Loomis and Cassman. 2011. Crop
Ecology: Productivity and Management in Agricultural
Systems. Cambridge University Press.
New York. (p. 297-299)
• Ingham, E.R. Soil Biology. The Soil Biology
P r i m e r .
http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html
bacteria.html
• Furseth, B., Davis, V. M., Casteel, S. N.,
Naeve, S. L., and Conley, S. P. 2011. Soybean
seed yield was not influenced by foliar applications
of sugar. Online. Crop Management
doi:10.1094/CM-2011-0615-01-BR. Δ
DR. CHAD LEE: Extension Agronomist, University
of Kentucky