Soil Test Note – No. H006
Dr. Keith Steigler, Extension Horticulturist –
Fruits, Dr. Stanley L. Chapman, Extension Soils Specialist
FERTILIZER AND CULTURAL
SUGGESTIONS FOR NUT TREES
Lime is generally recommended for pecans when the soil pH is above 5.5.
A very high pH is likely to cause more problems than a low pH.
Young Nut Trees:
The growth of first-year pecan trees is normally very slow, and they do
not respond to fertilizer. Weed and
insect control and adequate water are essential for survival the first year.
Apply the recommended fertilizer in a broad band three feet wide starting
at least a foot from the trunk and in an increasing diameter as the size increases.
The fertilizer can extend to or beyond the drip line.
Fertilizer recommendations
based on soil tests should be considered as an initial guide only. Leaf analysis, observation of length and vigor
of terminal growth, leaf color, and amount of leaf production should provide
a continuing indication of tree needs. Nitrogen
and zinc are the two plant food nutrients usually required by nut trees, especially
pecan. The response of nut trees to
phosphorus is very rare, and response to potash is uncommon.
Several suggestions for determining the amount of fertilizer needed
are listed. They do not all agree exactly. Foliar analysis provides the best measure of
the fertilizer needed.
Fertilization of Large Nut Trees on Town Lots or Farmsteads:
Proper lawn fertilization with plenty of nitrogen fertilizer may be sufficient
for these trees. Broadcast nitrogen
(1/4 – ½ lb ammonium nitrate or equivalent per 100 sq ft) one or more times
in early summer to maintain good, green foliage. Tree roots extend double the drip line (limb
length). Hole punching is not necessary
and will likely cause unsightly clumps.
Mature bearing pecan trees
should make annual terminal growth of 5-10 inches. Younger pecan trees should make 12-36 inches of terminal growth
until bearing starts. Poor nut production
is expected from very weak or very long vegetative growth. Vary nitrogen fertilization up or down to obtain
the desired tree response.
Fertilization of Individual Trees:
When a lawn application
is not appropriate or does not provide sufficient terminal growth.
|
Years of Age or Inches of Trunk Diameter (the smaller) |
Soil Test P > 35 Soil Test K > 125 Lbs. Ammonium Nitrate Or Equivalent/Tree |
Soil Test P < 35 Soil Test K < 125 Lbs. 10-10-10 Or Equivalent/Tree |
|
Year of Planting (1st leaf) 1(2nd leaf, etc.) 2 3 4 5 6 10 14 19 23 27 30 |
0 ½ 1 1 ½ 2 3 4 8 12 20 30 40 50 |
0 1 ½ 3 4 ½ 6 9 12 24 36 60 90 120 150 |
Note: Apply fertilizer uniformly within or slightly
beyond the drip line; broadcast on the surface. Avoid heavy applications of fertilizer near the tree trunk.
Fertilizing
the Commercial Pecan Orchard:
Fertilization of the pecan orchard will vary considerably
with the cultural practices used. Apply
the suggested fertilizer at bud swelling or slightly before, about mid-March.
Cover or Treatment Around Trees
Lbs. N/A
Continuous pasture or grass cover
90-150
Spring Cultivation and summer vegetation
60
Winter legumes and spring cultivation
30
Zinc:
Treat for zinc deficiency if zinc rosette appears:
½ lb. Zinc sulfate or equivalent per year of age-up to 10 lbs. Under
trees on acid soils. Try zinc chelate soil treatment on yard trees
with soil pH higher than 7.1, or apply as foliar spray (zinc sulfate or chelate)
if equipment is available. Zinc sulfate
at 2 lbs. Per 100 gallons of spray or equivalent zinc material may be applied
as a foliar spray twice before the foliage is full grown.
Foliar
Analysis:
A foliar analysis program is available for pecan trees
through the University of Arkansas Agricultural Diagnostic Service Lab at
Fayetteville. Sampling instructions
and other information is available through your local county Extension Office.
__________________________
Revised February, 1989
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