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Northcentral
Higher nitrogen (N) prices are of concern for farmers who have not already
applied their N nor prepaid for this spring's requirements. Whether you're
dealing with the higher prices or not, here are a few points to consider about
N fertilization.
Account for all N sources
• When appropriate, sample soils to determine nitrate levels. Some universities
provide guidance on the timing, depth, and number of cores to take for these
samples as well as adjustments for precipitation.
• Figure in the nitrate concentration in irrigation water. Although the
amount of irrigation water used varies from year to year, average amounts used
over the past few years may serve as a basis for planning.
• Consider taking N credits after a legume. Legumes cause a greater net
mineralization of N from soil organic matter, reducing the N rates required for
subsequent crops.
• Account for N and other plant available nutrients recoverable from manure.
Consider different times of application
A portion of the N may be applied pre-plant, side-dressed, or interspersed
throughout the season. Generally, N applications become more efficient when
applied closer to the times when plants have greater N needs.
Watch and evaluate
Look for signs of nutrient deficiencies… not just N but other nutrients
as well. An end of season evaluation for N nutrition of corn is available with
the stalk nitrate test. This test can help determine if N nutrition was sufficient
during the season.
Consider bumping up the intensity of management
More intensive measuring and monitoring better characterize N needs and improve
the ability to evaluate current management approaches. Keeping more detailed
as well as more frequently updated records increase the chances of managing
N in ways that maximize profit in more areas of the field.
Northeast
Don't let nutrient deficiencies and depleted soils creep up on you. Many people
are unaware of the quantities of phosphorus (P) and potassium (K) removed from
the field with a crop harvest. The most recent USDA summary of average U.S. 2003
yields for alfalfa, corn, wheat, and soybeans are 3.24 tons/A, 142.2 bu/A, 44.2
bu/A, and 33.4 bu/A, respectively. Considering these crops and yield levels,
using coefficients published by PPI, corn and alfalfa remove the most P per acre,
at 63 and 49 lb P2O5/A, respectively. Soybeans come in third at 27 lb P2O5/A.
Wheat is fourth, with a U.S. average removal of 22 lb P2O5/A. By far, K removal
from fields is highest with alfalfa, at an estimated 2003 U.S. average of 194
lb K2O/A. Soybeans come in a distant second, removing an average of 47 lb K2O/A.
Average K removal by corn and wheat follow with an estimated 41 and 15 lb K2O/A,
respectively. Because the actual amounts of P and K removed can vary with different
conditions and yield levels, it is best to take a few grain or forage samples
and have them analyzed to determine nutrient content. Combine this knowledge
with yield records to calculate how much P and K are being removed from your
fields. Attention paid to his aspect of nutrient management will help prevent
nutrient deficiencies and depleted soils from catching you unaware.
Northern Great Plains
Focus on phosphorus this spring.
With spring just around the corner, it
is time to start making plans for the 2004 crop season. The most recent survey
of soil tests conducted by the Potash & Phosphate
Institute demonstrated, at a state and province scale, the varying phosphorus
(P) needs across North America. Phosphorus levels also vary among and within
fields, making more intensive soil sampling necessary in many situations.
Does a field area have enough P already or is
more needed? The only way to tell is to take a
good soil sample and have it tested by a reputable
laboratory. The Extension Service in each province
or state, as well as many laboratories, provide
guidance on how to take and submit a soil sample
and interpret lab results.
What are appropriate target soil test P levels?
Target levels can differ widely depending on local
conditions, management practices, cropping systems,
land tenure, and cash flow. There are generally
two approaches to setting target soil test P levels:
1) the buildup and maintenance approach, and 2)
the sufficiency approach.
The buildup and maintenance approach attempts
to minimize the risk of P limiting yields. However,
because of the higher fertilizer rates required
during the buildup phase, there is increased initial
risk that positive returns to fertilization will
not be gained in the year of application. Adequate
cash flow, available capital, and a longer-term
financial strategy fit well with this approach.
The objective of the sufficiency approach is
to keep soil test levels in the responsive range
(below the critical level for the crop grown) to
assure a higher probability that positive economic
returns to fertilization will be gained in the
year of application. The sufficiency philosophy
attempts to reduce short term economic risks, but
carries a greater risk that P may be yield-limiting.
By targeting appropriate P soil test levels and
keeping a watchful eye on P budgets and soil test
changes, farmers and their crop advisers can make
the adjustments they need to come ever closer to
optimizing their P inputs to meet their management
objectives.
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Southern/Central Great Plains
Many parts of the region have recently received much needed rainfall. This has
resulted in an improved wheat grain yield outlook for areas such as the Rolling
and High Plains of Texas and most of Oklahoma. Although most of the region benefited
from the recent rains, it caused problems for some in the way delaying field
work and planting (e.g., Texas Coastal Bend). On the other hand, much of Colorado
and western Kansas still suffer from low soil moisture conditions. Overall, wheat
conditions across most of the region are relatively good. Growers should make
sure that wheat has adequate nitrogen (N) to finish out the season. Where appropriate
and time permits, topdress applications should be made to take advantage of the
improved conditions.
The recent rains have also resulted in a significantly
improved outlook and potential for spring plated crops and summer forages
over much of the region. Considering the improvement in the soil moisture
outlook this season, producers and ag professionals need to make sure that
fertility does not limit productivity. A priority should be given to complete
and balanced fertility this spring. For example, consider that providing
adequate phosphorus and potassium… along
with N… increases the crops ability to efficiently extract soil moisture
and improves N use efficiency. Also, as we enter the spring and approach the
summer keep in mind that forage crops will need sufficient nutrition to get
a good start. Take into account nutrient removal when planning the fertilization
of hay and silage crops… remember, these crops have the potential to
remove tremendous amounts of nutrients from the field.
Southeast
Farmer and fertilizer dealer attitudes are upbeat for 2004. Everyone is hopeful
that the crop prices will continue to be as positive as they were in 2003.
Soil moisture across the region has been abundant to surplus. Field work has
slowed in several states as a consequence.
In late February, wet soils slowed some land preparation for peanut and corn
planting in the northern Peninsula and Panhandle areas of Florida. The wet
conditions also hindered some sugarcane harvesting in the Everglades, with
most on schedule. In Georgia, apple producers set out insect traps. Producers
applied pesticides and fertilizer to pastures and fields and finished up pruning
orchards.
Corn planting was active, as was planting and harvesting of several vegetable
crops, prompted by warm, dry conditions in the recent weeks in Georgia and
Florida. Citrus growers harvested several varieties. Fields were drying across
most of Georgia, allowing producers to fertilize small grains and pastures
where needed.
Cool season forages - Fertilization began as the warmer weather spurred
growth.
Wheat - Fertilization began in most states. In spite of the wet weather,
the crop appears in relatively good health.
Cotton - Production was expected to increase slightly in the region
in 2004. However, the expected world production (100 million bales) may be
slightly greater than world demand (98 million bales), according to leading
cotton marketing specialists.
Soybeans - Soybean acreage is expected to be higher in 2004. For the
first time in almost 20 years, fertilizer dealers, farmers, and crop advisers
appear receptive to information and education on soybean response to phosphorus
(P) and potassium (K). It's important to recognize soybean harvest removal
of P and K.
According to Farm Press On-Line
(March 8, 2004) - "World ending stocks of grains and oilseeds are expected
to be lower in 2004 than in 2003. This differs from the U.S. situation in that
only rice stocks are expected to decline in the U.S. in 2004. Correspondingly,
U.S. farm prices for grains other than rice are not predicted to increase in
2004 from the levels seen this past year."
"U.S. exports of vegetables, horticultural products
and tree nuts should increase slightly in 2004. Productivity and net farm
income are relatively high in Georgia when compared to other states, according
to the guide. As net income improves in the U.S. agricultural economy, economic
conditions in Georgia also should improve during the coming years."
West
With the season in full swing, sometimes it's useful to step back and look at
the tremendous contributions that agriculture makes to society. Fertilizer is
one of the undisputed contributors to modern food production. The production
of fertilizers, especially nitrogen, requires the use of non-renewable energy
sources. Since they are non-renewable and costly, these energy sources need to
be used as carefully as possible.
Solar energy (photosynthesis) is the principal source of captured energy in
crop production, as sunshine is converted into energy that can be harvested
for humans and animals in the form of food. Farmers must invest energy inputs
(such as fuel, fertilizer, labor, etc.) in order to maximize the conversion
of solar energy into yield.
A variety of agronomic studies have shown that
returns on energy investments are greatest when fertilizers are used appropriately
for crop production. Using energy inputs for agriculture does not "consume" energy,
but instead transforms energy into food. We consume bread, fruit, milk, and
meat as food, but not crude oil and coal.
Wasteful use of energy should always be avoided, but appropriately used inputs
in agriculture are one of the best energy investments we can make. Proper fertilizer
use gives excellent returns on investment in energy, finances, and environmental
stewardship.
Remember that the reason for agriculture's existence
is to supply energy for people in nutritious and flavorful forms… in
food!
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