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Spring 2008
Spring is a great
time to appreciate the diversity of agriculture
in the Southeast region. Vegetable and citrus
harvests are in full swing in Florida, potato
planting is underway in North Carolina, and land
is ready to plant 2 million acres of rice in
AR, LA, MS, and MO. Over 5 million acres of winter
wheat has been, or is being topdressed with N
fertilizer, with sugarcane not far behind. Corn
acreage is not expected to fall much from the
approximately 10 million acres planted last year.
However, cotton acreage may be lower than we’ve
seen in the southeast since 1983. Strong wheat
and soybean futures are pushing many growers
out of cotton for another year. The greatest
declines are expected in MS (31%), AR (30%),
and TN (29). In the eastern part of the region,
NC and SC are expected to reduce their cotton planting
by 22 and 20%, respectively.
Many growers are still
looking at nutrient inputs as a way to save money
in 2008. Dr. Larry Oldham, Nutrient Management
Specialist at Mississippi State, is responding
by saying : I’m hearing people
say they cannot afford fertilizer this year. The
question is…can you afford not to fertilize?” His
data show that while it is possible that the percentage
yield decrease due to not applying soil test-recommended
P and K may be minimal (8%), if fertilizer is not
used when soil tests are in the low range yields
can be as much as 25% lower. “At a 50 bushel
per acre potential soybean yield, taking 12.5 bushels
out of the picture, at $12 per bushel for soybeans,
the cost of not applying is $150. Management needs
to assess whether this is acceptable given their
production system and variables in addition to fertilizer
costs: soil-specific yield potential, irrigation,
pest management, weather, variety yield potential,
etc. Soils testing in the very low range require
even more detailed decision processes.” Jason
Kelley, Extension Wheat Agronomist in AR, echoes
these sentiments saying, “I believe cutting
back on fertilizer would be the wrong thing to do.
With grain prices at these levels, it does not take
much of a yield response to get your fertilizer money
back”.
Even considering the economics, it is critical that
growers continue to think about maximizing nutrient
use efficiency to maintain profitability and minimize
nutrient losses. Applying nutrients at the correct
rates at the right time of the growing season are
sure ways to improve efficiency.
Despite the declining acreage, grower interest in
K fertility of cotton is very high heading into the
2008 growing season. This interest was evident at
the recent Beltwide Cotton Conference, when a special
session on K fertility was standing-room-only. The
increased concern is likely because growers are reporting
K deficiency showing up in fields where it had never
been a problem before. For more information on K
fertility in cotton, see article
Number 5 in the Spring 2008 series of Plant Nutrition TODAY.
A more detailed look at K nutrition,
including the complexity of the K cycle, K in
soil, uptake mechanisms, K role in plants, and plant
response to K fertilizer is available in the slide
set "Advanced
Topics in K Nutrition".
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