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Georgia Grown - Pecans
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Georgia Grown - Pecans)
Pecans
 Pecans have been
an important part of southern diet and culture since before the
arrival of European settlers. The first successful grafts of the
pecan tree were done in 1846 by a Louisiana plantation gardener. The
cultivation of the pecan tree increased, and the technique of sowing
proved to be the most effective.
Today the tree is most widely cultivated in the states of New
Mexico, Louisiana, Mississippi, Georgia, Florida and Texas, where
the pecan tree is the official state tree.
Georgia is the nation's largest supplier of pecans, with more than
half the total U.S. production.
An average pecan harvest is about 100 million pounds. In 2001 the
crop was 95 million pounds and in 1993, the crop weighed in at a
record 150 million pounds.
The state's major pecan-producing region is near Albany, in
south-central Georgia, although there are large and small orchards
from Atlanta southward.
Pecans are often associated with the traditional pie or pralines but
they are used in a variety of recipes, from cookies and desserts to
salads and main dishes. Pecans can replace just about any nut in
cookies.
Pecans are available in many forms; you'll find them vacuum- packed
in jars, sealed in plastic bags, or packed in cans. For the freshest
and most flavorful pecans, choose whole ones in the shell; look for
nuts that are heavy for their size and don't rattle when shaken.
There shouldn't be any cracks or holes in the shells. When you buy
shelled pecans, look for a date on the bag or container. Shelled
pecans absorb odors and turn rancid quickly, and should be stored in
the refrigerator in a sealed container.
Pecans can be stored in the freezer for up to two years, so if you
buy more than you can use right away, store them in a moisture-proof
plastic bag in the freezer. Unshelled pecans may be stored for about
3 months at room temperature.
Even though pecans have a high fat content, they're a good source of
potassium, thiamine, zinc, copper, magnesium, phosphorous, niacin,
folic acid, iron, and vitamin B6, they are also a good source of
fiber.
Pecans are rich in oleic acid, a mono-unsaturated fat believed to
help in preventing heart disease.
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 Pecan
History
During the late 1800's landowners began to recognize the potential
profit of pecans in the southeastern United States . By the late
1800's several individuals near Savannah, Georgia had produced and
marketed pecans on a small scale. By 1889 there were only 97 acres
of pecans planted in Georgia .
Thousands of acres of pecan trees were planted in Southwest Georgia
between 1910 and 1925. Most of these trees were initially planted as
real estate investments rather than for nut production. Thousands of
acres were sold in five and ten acre units, primarily in Dougherty
and Mitchell Counties , which are still today the hub of Georgia's
pecan producing counties. By 1920, Georgia was producing 2.5 million
pounds of pecans.
By the 1950's Georgia was ranked as the top state in the nation for
pecan production.
Today, Georgia pecan orchards may range in size from just a few
trees to several thousand acres. The state continues to be regarded
as the top pecan producing state in the U.S. , with over 140,000
acres planted to pecans. An early harvest date compared to other
areas of the nation which produce pecans, often results in good
prices for Georgia pecan growers, who produced $128,499,337 in farm
gate value during 2007.
Although the pecan has a long history in North America, Georgia
farmers were relative latecomers in realizing the benefits of this
tree nut. By the 1950s, however, Georgia had become the country's
leading producer of pecans. As of 2006 Georgia remains the largest
pecan-producing state in the nation.
Pecan (Carya illinoensis) is a common name for a species of hickory
in the walnut (Juglandaceae) family. According to archaeological and
historical evidence, Asian species of the hickory tree arrived in
North America before the first humans crossed the Bering Strait from
Asia about 10,000 B.C. Other species are native to the Mississippi
River valley. The tree typically grows to a height of 75 to 100 feet
and is well adapted to Georgia's sandy loam soil with clay subsoil.
The term pecan is also applied to the tree's edible fruit. The nuts
have a rounded, oblong shape and vary in weight from 25 to 100 to
the pound.
While there may have been wild pecans in some of Georgia's river
valleys, the nuts are generally regarded as nonnative to the state,
and their value as a potential cultivated crop was not recognized
until the late nineteenth century. By that time landowners began to
regard pecans, long a staple of wild native trees from Iowa and
Indiana to Texas and Mexico, as a commercial crop. Commercialization
of pecans allowed the nut crop to expand into a number of
southeastern states (including Georgia) and to New Mexico and
California.
In the late 1800s several individual Georgia landowners near
Savannah began producing and marketing pecans on a small scale
(about ninety-seven total acres by 1889). By 1910 a "pecan boom"
began when southwest Georgia landowners started planting what became
thousands of acres of pecans. The orchards, however, were not looked
upon as a commercial agricultural venture but as a real estate
enterprise. Most of the acreage planted during the fifteen-year
boom, from 1910 to 1925, were sold as five- to ten-acre units for
homes or small farms. Most of this acreage was concentrated in
Dougherty and Mitchell counties.
Those early-twentieth-century plantations consistently remain the
center of Georgia's pecan-producing counties today. Modern orchards
with plantings of scientifically improved pecan varieties now yield
what are called "paper shell" pecans, so named because the nuts are
easy to crack and shell.
By the 1920s Georgia was producing 2.5 million pounds of pecans. As
of 2006 Georgia pecan orchards range in size from just a few trees
to several thousand acres, with more than 142,500 acres planted.
Georgia is also fortunate to have an early harvest date compared to
other pecan-producing areas, which often results in good prices for
Georgia growers. They produced about 45 million pounds in 2004 and
70 million pounds in 2005. The farm-gate value for the crop in 2004
was more than $121 million.
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Harvesting & Storage
 Harvesting pecans
occurs from mid October through November, and occasionally into
December. For home harvesting, gathering falling nuts can be an
option, but you usually have to fight the squirrels, who are master
nut gatherers. Small harvests can be achieved by tapping limbs with
a padded stick to help with nut drop, or commercially tree shakers
are used. Mechanical shakers are fascinating to watch. Once secured
on the trunk of the tree, they are turned on and the tree shakes
rapidly, causing the nuts to drop like pelting rain. Standing
nearby, even the soil vibrates. Then the nuts are gathered, removed
from their outer husks and sorted. Pecan nuts lose quality very
quickly on the ground, especially during wet weather, so it is
important to harvest soon after shaking. Fresh pecans need to be air
dried for two to three weeks before storing.
Pecans will oxidize or turn rancid more rapidly in light and out of
their shell, so nuts will store longer when they are in their shell.
If you don’t intend to use them right away, you may want to buy
unshelled nuts. They are best stored in a cool, dry, protected
location. If you plan to store them for more than a month, you might
consider freezing them. For the highest quality product it is
recommended that they not be stored for more than one year in the
freezer, but they have been known to do fine for several years.
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 Fertilization
Proper nutrition is a key requirement for the reliable production of
pecans. Like other plants, pecans require nutrients for growth and
fruit production. Fertilizers supply nutrients to soils and help to
correct nutrient deficiencies. Four of the six macronutrients needed
by pecans are commonly deficient in Georgia soils. These include
nitrogen, potassium, phosphorous, and magnesium. Two of the seven
micronutrients required by pecans are commonly deficient as well,
zinc and iron. Recent attention has also been given to deficiencies
of nickel and boron.
The single most reliable indicator of the nutritional needs of the
pecan tree is the foliar or leaf analysis. Soil samples are less
efficient for determining nutritional deficiencies in mature
orchards, but are quite useful for monitoring soil pH and lime
requirements. Leaf analysis is more sensitive to changes in nutrient
supply because it measures amounts of specific nutrients in the
leaves. Leaves should be sampled for analysis between July 7 and
August 7 as this is the period in which nutrient concentrations in
the leaves are most stable. Nutrient Sufficiency levels are given in
table 1.
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Table 1.
Sufficiency levels for essential elements.
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Element Sufficiency Range
N (%) 2.5-3.3
P (%) 0.18-0.2
K (%) 1.3-2.5
Mg (%) 0.35-0.6
Ca (%) 1.3-1.75
S (%) 0.25-0.5
Zn (ppm) 50-100
Fe (ppm) 50-300
Mn (ppm) 100-800
B (ppm) 15-50
Cu (ppm) 6-30
Ni (ppm) 5-15 |
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Nitrogen
Nitrogen is the element that most commonly limits pecan growth and
ultimately orchard profitability. It provides better tree growth, a
higher percent kernel, and a healthier tree. When properly
maintained, nitrogen can help to provide optimal year to year
production. Nitrogen deficiencies result in poor growth and poor
tree health. Too much nitrogen stimulates excess foliage, shading,
and in some instances reduced yield. The key to nitrogen management
is to balance applications with the needs of the tree.
The management of nitrogen fertilization in the pecan orchard will
vary for irrigated versus non-irrigated orchards and from one year
to the next within a given orchard, depending upon crop load.
Nitrogen uptake in the pecan tree is driven by demand. There are two
critical periods of nitrogen demand during the season; (1) early
foliage growth and (2) kernel filling. The early spring foliage
flush is nourished primarily from reserves held within the tree,
while the nitrogen demand during the kernel fill stage is satisfied
from an earlier application made during the current season.
In the absence of leaf sample recommendations, dry land orchards
should be fertilized with 75 lbs of N in late February or early
March so that winter rains will help to improve soil moisture and
ultimately nitrogen uptake. For irrigated orchards, soil moisture,
and thus nitrogen uptake can be more easily controlled by the
grower, which provides for more efficient use of nitrogen by the
tree.
Nitrogen recommendations have evolved greatly over the years.
Historically, recommendations for orchards have been to apply
nitrogen in March or as a split application in March and May. A
general “rule of thumb” for mature, well managed, irrigated orchards
is to apply 10 lbs of N /acre for every 100 lbs. of expected crop.
An alternative is to split the application between mid-spring and
late summer. This timing works best for orchards bearing heavy crops
and where other limiting factors are controlled. Well managed trees
coming off an “off” year, begin spring foliage growth with a full
supply of nutrients stored in the stems, trunk, and roots. As a
result, there is little demand for nitrogen and healthy trees will
not remove nitrogen from the soil at this time. A more efficient use
of nitrogen may be to apply 1/3 of the nitrogen required when the
shoots are 75% expanded, which generally occurs in mid to late April
in Georgia.
During “off” years, the April application alone as described above
is sufficient. During July, trees may be assessed with regard to
their crop load. If the crop load is heavy, another 1/3 of the full
rate should be applied in early August. The final 1/3 should be
applied in early September to help maintain healthy foliage for
optimum kernel filling, leaf retention, and ultimately adequate
nutrient storage pools. For example, with an expected crop of 1500
lbs/acre, the N would be applied as 50 lbs/acre in mid-late April,
50 lbs in early August, and 50 lbs in early September.
The kernel filling process pulls nitrogen from the leaves. During an
“on” year with heavy crop loads, these leaves must have soil
nitrogen to remain healthy and fully functional.
Once the kernel-filling process is complete, healthy leaves will
maintain sufficient nitrogen to produce stored food. Trees in the
“off” cycle of production will have sufficient nitrogen and will not
need late-summer applications.
Though more complex than the March or March/May applications, spring
and late summer splits make for more efficient use of nitrogen by
the tree and can help reduce the alternate bearing tendency in well
managed orchards.
Phosphorous
Phosphorous is important for energy storage as well as the
production of wood and nuts. Despite its value, phosphorous levels
in Georgia soils are often adequate, and additional phosphorous
should not be applied unless called for by leaf analysis. The
predominant symptom of phosphorous deficiency is a dull green
foliage with no intervienal chlorosis.
Such deficiencies are often over-looked and are easily mistaken for
mild nitrogen deficiency. In heavy bearing varieties, phosphorous
efficiency can be expressed as a marginal leaf scorch, which may
begin 7-10 days before shuck split and premature defoliation. High
concentrations of phosphorous can inhibit the uptake of nitrogen, as
well as iron, zinc and copper, by the pecan tree.
Phosphorous is relatively immobile in the soil, so single
application of 60-100 lbs of P2O5 incorporated at planting can last
for several years. Subsequent applications as needed should also be
incorporated because surface applications may require several years
to be of benefit to the orchard. Applications should be made any
time leaf levels fall below 0.12 percent.
Potassium
Potassium is essential for the movement of carbohydrates, regulation
of osmosis, and the activation of enzymes within the pecan tree. The
resistance of pecan trees to winter injury is also heavily
influenced by potassium levels.
Maintaining an appropriate balance of nitrogen and potassium within
the tree is of vital importance. If leaf potassium content is near
minimum levels, heavy nitrogen applications will induce a visible
potassium shortage termed nitrogen scorch. Nitrogen scorch can lead
to serious defoliation, which appears first on the basal shoots and
leaves, progressing upward. Scorched areas occur along the leaf
margins, and are circular or oblong and about the size of a dime.
Desirable, and to some extent, Schley trees are often especially
sensitive to the nitrogen-potassium imbalance.
Less severe symptoms of potassium deficiency begin as an irregular
interveinal chlorosis. As potassium concentrations decrease through
the season, the chlorosis may spread up the shoot and leaf. Necrotic
spots may develop on the surface of the leaf.
Transport of potassium from the leaves to the fruit often
accelerates potassium deficiencies, particularly in heavy crop
years. Such deficiencies may induce premature defoliation, shoot
die-back, and small, poorly filled nuts. Careful monitoring of leaf
nitrogen and potassium levels is required to maintain optimal
nutrition.
The most common method of supplying potassium is by soil application
of muriate of potash. Rates should be based on leaf potassium and
the amount of nitrogen applied.
The N/K ratio should be maintained at 2:1 for most varieties in
order to prevent leaf scorch. Applications should be made in
February before the onset of winter rains.
Where late summer applications of N are used, additional
applications of K should be made at that time if K levels in the
leaf are marginal.
Magnesium
Magnesium deficiency is relatively rare in pecan; however, it can
occur in trees growing on acid or sandy soils, especially in
orchards with high soil potassium levels. Magnesium deficiencies are
characterized by an intervienal chlorosis , which forms a “Christmas
tree” pattern on the leaf. In very severe cases, a marginal leaf
scorch may follow chlorosis.
Magnesium deficiency is best prevented by maintaining soil pH at
6.0-6.3 and by the use of Dolomitic limestone as a liming material.
Dolomitic limestone contains both calcium and magnesium, and
generally provides an adequate amount of magnesium for most
orchards. Growers will usually be able to observe increases in their
leaf magnesium levels the second growing season following
application. Where trees are identified as magnesium deficient,
magnesium sulfate is more effective at raising leaf magnesium
levels, because it is more water soluble. Deficient trees ill
respond more quickly to foliar sprays of magnesium sulfate (5
lbs/100 gal) applied from the first leaf stage through July, but
soil application of magnesium will still be necessary to maintain
adequate levels in orchard soils.
Zinc
Zinc has a major influence on the economic return of a pecan
operation due to its effect on flowering, fruit size, leaf
efficiency, and nut yield. It is particularly important to leaf
expansion and shoot elongation. As a result, zinc must be available
to the tree at these specific times during the growing season. The
most familiar characteristic of zinc deficiency is pecan rosette,
which begins as chlorosis and curling of young leaves, resulting in
a wavy leaf margin. Additional symptoms may be a rosette pattern,
narrow leaves, and terminal die-back.
Even with adequate soil levels, the availability of zinc in the soil
depends upon soil pH, nitrogen, and phosphorous application. Liming
soils with marginal zinc levels can reduce zinc uptake, particularly
when nitrogen and phosphorous are applied in combination with lime.
Zinc can usually be maintained at adequate levels under a liming
program on acid soils if zinc is also applied. One advantage of soil
applied zinc is that one application should provide an adequate
supply of available zinc for many years to come.
Zinc moves slowly in the soil, requiring two or more years for a
surface application to become effective. Therefore, foliar zinc
applications are the most effective means of correcting the problem
when deficiencies occur. Three to six applications per season are
normally recommended, depending on the severity of the deficiency,
with the first spray being applied about two weeks after bud break.
Sprays should be applied at 2 week intervals over the period of
shoot elongation. Foliar zinc should be applied anytime leaf
concentrations fall below 50 ppm or when visible symptoms of zinc
deficiency are present. For rates to apply, see the current pecan
spray guide.
Iron
As a component of chlorophyll, iron is essential to the process of
photosynthesis. Iron deficiency rarely occurs from lack of iron in
the soil, but is induced by over-liming, cold, wet spring weather,
or high concentrations of zinc, phosphorous, or manganese in the
soil. The deficiency generally occurs early in the growing season,
and clears up as the season progresses.
Symptoms of iron deficiency look similar to nitrogen deficiency,
exhibiting chlorosis of the leaf. The interveinal chlorosis in iron
deficiency sometimes retains very pronounced green veins. Also, with
iron deficiency, young leaves are the first to be affected.
Depending upon the cause of iron deficiency, correction may take
varying routes, including foliar applications of iron, changing the
amount of lime applied to the orchard, or foregoing phosphorous
applications. In most cases, the problem will clear up as the season
progresses, especially when due to cool, wet spring conditions.
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Georgia Grown - Pecans) |
