Managing Nutrients

Managing Nutrients


[ Silence ] [ Music ]>>As you’ve seen in the
earlier segments of this series, naturally healthy soil is much more
efficient at storing and cycling nutrients. Over time, you’ll be able to grow crops
with far less chemical fertilizer, but the first few years can be challenging. Before we talk about ways to deal with
those challenges, think back for a minute on what we know about developing healthy soil. Remember, the main problem with
tilling crop residue into the soil. When plant material is buried, it gives the
following crop a quick boost of nutrients. Very little soil or organic
matter remains to store and cycle the nutrients from
your chemical fertilizer. Any nutrients the plants
don’t use are lost for good. But now you’ve begun reducing soil disturbance and you’re keeping the plant
residue on top of the soil. Organic matter is starting to build up
in your soil but you’ve got a problem.>>It takes time, and those first 3 to 5 years
are the most difficult for this whole process. In fact, you’ll probably have to use
more fertilizer; you’ll probably have to use more herbicides those first 3 to 5 years.>>This is because the soil organisms
that are building organic matter are able to use the nutrients before your plants are. At first, you’ll need to feed both
the plants and the soil organisms.>>The first thing that comes back is
the soil structure and the infiltration, and the most difficult one to
get back is the nutrient cycling, and that one takes feeding the soil system, feeding it with diversity;
diversity, diversity, diversity.>>Remember, once you established
productive soil in the field, you’ll gain about 1000 pounds
of nitrogen for every 1% of SOM. The good news is that as you build SOM,
your nutrient efficiency is rising as well; more nutrients are available to your plants
and less is leaking into the environment. Depleted soil is like a leaky faucet. More organic matter in the soil
along with all he organisms that grow in the organic matter is able to stop the
nutrient leak, and along the way you’ve cut down on the amount of nutrients that were
flowing into ponds, streams, and ground water. Good nutrient management
begins with good information. Accurate soil test data is vital. Develop a nutrient management plan that
takes into account your cropping history, which crops you expect to grow in the future, and realistic yield goals
for the upcoming crops. Solid recordkeeping is also important when
you begin your work to rebuild depleted soil. Accurate records enable you to monitor the
buildup or depletion of nutrients over time and avoid being caught off guard by
the nutrient demands of your crops. You may not be aware that
most agencies responsible for fertilizer recommendations make those
recommendations based on conventional tillage. Nitrogen recommendations don’t take into the
account the amount of organic matter present in your soil and your surface residue history;
however, your soil test laboratory will be able to analyze your soil for organic matter content. It’s very important that you
start tracking SOM levels as you begin a program of reduced tillage. After 5 or more years of no-till or
strip-till, and with a mature residue layer, you may be able to take a nitrogen credit. A rough rule of thumb is between
30 and 50 pounds per acre. If you suspect that your soil organic matter
is now able to provide a substantial amount of nitrogen for your crops, you can
get an idea of your nitrate levels through the Presidedress Nitrogen Test. Often the results of this test give farmers the
confidence to reduce their sidedress nitrogen by as much as 50 pounds per acre. Interpreting the results of a Presidedress
Nitrogen Test requires expertise. Talk to your NRCS agronomist or
to farmers and extension agents who have experience with
it before you get started. Cutting back on nitrogen fertilizer doesn’t come
without some risk, and you’re probably reluctant to take any steps that might result
in lower yields and a loss in income. And nothing says you have to back
off on nitrogen everywhere at once. You can set aside part of a field to experiment
with lower amounts of sidedress nitrogen and then compare the yields
with the rest of the crop. With time and experience, you’ll
develop a sense for how the changes in your farming practices are
affecting the fertility of your soils.>>We decided with the help of a District
Conservationist who gave me a lot of help, John Timmons, that we should cut down on
this fertilizer and see what it would do. We planted some test plots where
we cut it down to half, a fourth, and some of them with none in it. The one that we didn’t have any nitrogen
on we took a tissue sample and sent it off and there was nothing lacking in it. So I decided if I didn’t need it, why buy it?>>You may be used to taking a 40-pound
credit for a crop that follows soybeans. Legume cover crops typically deliver an
even greater benefit that can be considered when you work out your nitrogen needs.>>One of the last hurdles for me personally
as a County Agent and making recommendations on nutrients was can we have the confidence
that that nitrogen is out there and is available for the plant during the growing season? And I guess it was somewhat of a
process, but where we’ve gained that confidence is just actually
reducing our amount of nitrogen going into the growing season that we would apply. In corn, we took a really big step last year
and reduced our nitrogen application by 50%, and in this particular field I’m standing in, as
far as I know, it was our highest yielding field of corn in Turner County last year. And then with cotton, cotton production
of 12, 13, 1400 pounds with only 30 units of nitrogen compared to where we’d be
recommending applying a commercial application of nitrogen, commercial fertilizer
of the 100 to 125 pounds. We’ve grown some 60, 70 bushel grain sorghum
with no nitrogen application, so it’s there; we just got to take that leap of faith or
step out there and know that it’s available.>>Phosphorus, potassium, and micronutrients are
typically more stable in the soil than nitrogen. For this reason, it makes more
sense to use the recommendations that come back from your soil tests. But here, too, you can expect
healthy soil to conserve nutrients. Fields under reduced tillage, and especially
fields that have been cover-cropped, generally consume less chemical
phosphorus, potassium, and micronutrients [Background Music]. For more information on nutrient management,
you can consult NRCS Conservation standard #590 or contact your local NRCS or extension office.

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