Midwest Vegetable Guide - 2022 - 20

Soil Fertility and Nutrient Management
ground limestone reacts with soil more quickly than normal
limestone. In fluid lime, 100 percent of the liming material
must pass through a 100-mesh screen, and nearly 80 to 90
percent must pass through an even smaller 200-mesh screen.
The principles of effectiveness of ground agricultural lime
also apply to fine or fluid lime. Lime suspensions do not
possess any special capabilities compared with conventional
agricultural lime that contains a high degree of 60-mesh or
finer particles.
Pelletized lime, or pell-lime, is finely ground lime that has
been formed into pellets for easy application. Because it is
finely ground, it will react quickly in the soil. Unlike regular
ag lime, it will not provide residual liming activity over a few
years.
Liming Recommendations
Fields usually require lime every few years because Ca and
Mg are removed in harvested portions of the crop, leached
out of surface soil by rainfall, and lost from the field when
soil erodes. Lime is also needed to neutralize acidity
produced by acid-forming fertilizers.
Growers sometimes need to add lime to correct subsoil
acidity. In that case, apply enough lime to bring the surface
soil to pH 6.8. The subsoil pH will increase only if you
maintain the surface pH near 6.5 or more. Over time, rain
will leach the Ca and Mg into the subsoil, raising its pH.
Because this downward movement takes several years, the
sooner the lime is applied, the better.
In most cases, make split applications when the
recommendation is more than 4 tons per acre. This will
achieve a more thorough mixing with the acidic soil.
Apply half the lime before plowing and half before soil
fitting. For best results, apply the lime at least six months
before seeding a legume.
If you have a recommendation for a maintenance application
of 2 tons per acre or less, you can apply it at any time in the
cropping sequence.
Plant Tissue Analysis
Plant tissue analysis for nutrients is a useful tool in managing
plant health, and a tissue test is usually required to confirm a
diagnosis of nutrient deficiency. Tissue testing can be
especially helpful when growing a new crop or a familiar
crop in a new production system.
Regular tissue tests, especially early in the growing season,
will provide early notice of nutrient imbalances so they can
be corrected before yield or quality is affected. With high
value greenhouse crops regular tissue testing is often a
standard part of production.
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Concentrations of nutrients in plant tissue that are normal,
deficient, or excessive have been identified for most
vegetables. The concentrations depend on the plant part and
stage of growth. Before collecting plant tissue, contact a
tissue testing lab and request instructions for collecting and
submitting samples. The specific plant part to collect for
tissue analysis varies depending on the crop; often it is a
recently mature leaf. The stage of crop growth is important
because normal tissue nutrient concentrations change as the
crop develops.
If the tissue test is being used to diagnose a specific
symptom, collect separate samples from each of these groups:
* Symptomatic plants
* Healthy plants
* Plants with minor symptoms
Comparing the results of these three samples, along with
results of soil tests, can help in determining the problem. For
assistance in interpreting plant tissue tests, contact your
local extension vegetable specialist.
Chemigation Management
Chemigation is the process of applying an agricultural
chemical (pesticide or fertilizer) to the soil or plant surface
through an irrigation system. Depending on the type of
agricultural chemical, chemigation may be referred to as
fertigation, insectigation, fungigation, etc.
For chemigation applications, you can only use pesticides
that display EPA approval for such applications on the
label. Each chemigation and irrigation system also must use
the safety equipment specified on the EPA label as well as
any equipment required in your state. Some states also may
require a system or operator permit before you can apply
any product with chemigation.
Chemigation can be an effective application option for some
labeled pesticides if the irrigation system can apply the
chemical/water solution uniformly over the target area with
the correct water depth. Some pesticides work best with less
than 0.25 inch of water per application.
Most late-model center pivot and linear move systems
provide adequate distribution but some may not be able to
apply a small enough volume of water. Solid set sprinkler
systems may be effective for some pesticides but require
close timing of chemical movements to get complete and
uniform coverage of the field. Drip irrigation can be used
effectively to apply certain pesticides and fertilizers.
Traveling gun and hand move systems do not provide water
distribution that has high uniformity and are not
recommended. Product labels provide more information
about appropriate water application amounts and which
irrigation systems are recommended.
Midwest Veg Guide 2022
Midwest Vegetable Guide - 2022

Table of Contents for the Digital Edition of Midwest Vegetable Guide - 2022
