and his co-workers collected petioles from leaves opposite clusters during
bloom. They found phosphorus concentrations between 0.04% and 0.07% (400 to 700
ppm).6 In California, phosphorus concentrations in
petioles during bloom normally range from 0.3% to 0.6%,6 and petiole phosphorus concentrations lower than 0.10%
(100 ppm) have been considered deficient.4 However,
recent research indicates that the leaf tissue phosphorus concentration
associated with deficiency may vary with scion and rootstock variety.
Ungrafted vines have been
shown to generally differ in petiole phosphorus concentrations,2,5 and the varieties Chardonnay and
Chenin Blanc to differ in the leaf blade phosphorus concentration associated
with maximum yield (Fig. 1).15
Scion and rootstock influence the extent that vine growth and leaf area are
inhibited by phosphorus deficiency.7
addition, rootstocks differ in their ability to take up phosphorus from the
soil, to translocate phosphorus to the scion, and in their influence on
phosphorus use efficiency by the scion.8 These
observations suggest that a single leaf tissue phosphorus concentration may not
accurately diagnose phosphorus deficiency in all scion-rootstock combinations.
Until further research involving several scions, rootstocks, and soil
phosphorus levels is conducted, the 0.10% criteria should be used
Plant nutrients required
in large quantities, such as phosphorus, are called macronutrients.
Macronutrient deficiencies are usually corrected by applications of fertilizers
to the soil. In field trials, applications of phosphorus fertilizer to soils
have successfully corrected phosphorus deficiencies.6,15 Fertilizer was placed on the soil under the drip
emitters by hand. Maximum fruit yields were achieved at 0.3 to 0.4-lb
phosphorus per vine for vineyards with conventional vine densities.15
The beneficial effects of the fertilizer declines with time and reapplication
becomes necessary after two or three years.
Triple superphosphate and
monoammonium phosphate, two commonly used phosphorus fertilizers, were used in
the trials.15 There was evidence in this and other
studies that the nitrogen present in the monoammonium phosphate fertilizer
enhanced phosphorus uptake and utilization by P-deficient plants.19
The application rates for
phosphorus fertilizers are relatively high compared to those used for other
macronutrients such as nitrogen. Such high rates are necessary because low pH,
P-deficient soils adsorb or fix large quantities of phosphorus. This makes it
necessary to apply P-fertilizer in a concentrated band or spot in order to
overwhelm the soils adsorption capacity leaving some phosphorus available
to the vines. With lower rates or broadcast applications, most of the applied
phosphorus is adsorbed by the soils and not enough is left for the
Lower application rates
are required when correcting P deficiency with soluble phosphorus fertilizer
applied through a drip system.12,13 Savings will be realized both in the quantity of
phosphorus fertilizer applied and the labor required for application.
Fertilizer may be applied
through a drip system at any time during the season until leaf fall, but is
probably most effectively applied during the spring and autumn while roots are
It is essential that only
soluble phosphorus fertilizers be applied and that only very low concentrations
of calcium and magnesium be present in the water flowing through a drip system
while phosphorus is being injected to avoid emitter clogging. When their
concentrations are sufficiently high, calcium and magnesium combine with
phosphorus to form the solid compounds calcium phosphate and magnesium
phosphate. Precipitation of these compounds can be avoided by acidifying the
irrigation water, which is accomplished through injection of acidic fertilizer
or simultaneous injection of acid and fertilizer.
Many growers inject
sufficient acid to lower the irrigation water pH between 5.5 to 6.0. Fertilizer
is normally applied during the middle of an irrigation set to allow prewetting
of the soil prior to the application and flushing of the drip system following
Rock phosphate, the raw
material from which commercial phosphorus fertilizers are made, is commonly
used by organic growers to correct phosphorus deficiencies because other
fertilizers accepted by organic certifying organizations contain much less
phosphorus. (Examples of other phosphorus-containing fertilizers accepted by
organic-certifying organizations include compost, bone meal, and kelp-based
Rock phosphate will not
be effective in correcting phosphorus deficiencies if it dissolves too slowly,
allowing much of the phosphorus to be adsorbed by the soil and leaving little
phosphorus for the vines.
with rock phosphate occurs when it is derived from apatitic phosphate rocks
containing a high percentage phosphorus (see Table I),
finely ground, and applied at very high rates (two to three times higher
phosphorus rates than conventional phosphorus fertilizer) in a concentrated
band or spot.19 Rock phosphate has the
disadvantages of uncertain effective phosphorus concentration and rate of
release, and the inconvenience of greater bulk and dust compared with
conventional phosphorus fertilizers.
Composition of selected phosphorus fertilizer materials.
|Raw rock phosphate
|Defluorinated phosphate rock
|Magnesium silicate phosphate rock
|Phosphoric acid z
|Superphosphoric acid z
|Monoammonium phosphate z
||20 or 39
||9 or 17
|Ammonium polyphosphate z
|Monopotassium phosphate z
|z Some or all fertilizer materials of this
type are suitable for drip irrigation. Verify suitability with fertilizer
supplier before using
Regardless of the type of
phosphorus fertilizer, it is beneficial to apply it to low-P soils in advance
of planting a new vineyard to allow it time to saturate the soils
P-adsorption capacity and become available for vine uptake. This is most easily
accomplished by shanking dry fertilizer adjacent to the vine row or injecting
liquid fertilizer through the drip system. Hand application in the planting
hole is more costly and may result in young, tender vine tissues coming into
direct contact with concentrated fertilizer.
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"Aluminum and iron phosphate studies relating to soils, II. Reactions
between phosphate and hydrous oxides." J. Soil Sci. 15: 110-116 (1964).
2. Brunstetter, B.C., A.T. Myers, I.W. Dix, and C.A. Magoon.
"A quantitative survey of eight mineral elements by a spectrographic
method and of total nitrogen in young leaves of 25 varieties of American
grapes." Proc. Am. Soc. Hort. Sci. 37: 635-638 (1939).
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4. Christensen, P., A.N. Kasimatis, and F.L. Jensen. Grapevine
Nutrition and Fertilization in the San Joaquin Valley. Univ. Calif., Berkeley
5. Christensen, P. "Nutrient level comparisons of leaf
petioles and blades in 26 grape cultivars over three years (1979 through
1981)." Am. J. Enol. Vitic. 35: 124-133 (1984).
6. Cook, J.A., W.R. Ward, and A.S. Wicks. "Phosphorus
deficiency in California vineyards." Calif. Agric. 37: 16-18 (1983).
7. Grant, R.S. and M.A. Matthews. "The Influence of
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Area, and Petiole Phosphorus Concentration." Am. J. Enol. Vitic. 47:
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aluminum systems, I: Adsorption of phosphate by X-ray amorphous aluminum
hydroxide." Can. J. Soil Sci. 42: 197-209 (1962).
10. Marschner, H. Mineral
nutrition of higher plants. Academic Press, London (1986).
11. Menge, J.A., D.E. Munnecke, E.L.V. Johnson, and D.W.
Carnes. "Dosages responses of the vesicular-arbuscular mycorrhzal fungi
Glomus fasciculatis and G. constrictus to methyl bromide." Phytopathol.
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12. ONeill, M.K., B.R. Gardner, and R.L. Roth.
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Irrigation." Soil Sci. Soc. Am. J. 43: 283-286 (1979).
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and R.G. Burau. "Phosphorus fertilizer with drip irrigation." Soil
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of phosphate fertilizers in soils." In: The role of phosphorus in
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15. Skinner, P.W., J.A. Cook, and M.A. Matthews.
"Responses of grapevine cvs. Chenin Blanc and Chardonnay to phosphorus
fertilizer applications under phosphorus-limited conditions." Vitis. 27:
16. Skinner, P.W., R.S. Grant, and M.A. Matthews.
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nutrient levels of Cabernet Sauvignon (Vitis vinifera L.) Lamina." In:
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