Publication 360, Fruit Production Recommendations: Chapter 6: Grapes

Publication 360, Fruit Production Recommendations:
Chapter 6: Grapes > Grape Nutrition

Pub 360, Fruit Production Recommendations > Chapter 6: Grapes > Grape Nutrition

Excerpt from Publication 360, Fruit Production Recommendations 2010-11,
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Table 6-1. Nutrient Sufficiency Range of Grape Petioles

Introduction

Test the soil a year in advance of planting grape vines, or two years before planting where pH adjustment may be necessary. Several soil amendments do not move readily through the soil profile, but are needed to optimize vineyard productivity. These materials include organic matter, phosphorus, potassium, and lime to adjust soil pH. The only opportunity to thoroughly incorporate these materials is before planting.

Manure for Vineyards

Manure can pose a food safety risk on many fruit crops. Ensure at least 120 days between manure application and harvest.

Manure contains beneficial organic matter and provides many macro and micronutrients. The organic nitrogen in manure is mineralized over time, providing nitrogen in diminishing quantities for several years after application. When manure is used, adjust applied inorganic nitrogen to avoid over applications. Excessive nitrogen, particularly in the second half of the growing season, can result in poor fruit colour, excessive growth and delayed hardening of the woody tissue, which may make plants more susceptible to winter injury.

Observe the following guidelines to receive the benefits of manure while minimizing potential problems:

Apply no more than 7 tonnes/ha of poultry manure (20 m³ liquid), 40 tonnes/ha of cattle manure (100 m³ liquid) and 35 tonnes/ha hog manure (65 m³ liquid). Since the nutrient content of manure varies considerably, it should be tested before application. See Manure nitrogen.
Broadcast manure and work it into the soil in late fall or early spring before planting.
Do not place manure around newly planted vines as winter injury may result.
Adjust the rate of nitrogen, phosphorus and potassium fertilizers applied according to the nutrient content of the manure. See Table 3-11. Average Fertilizer Replacement Values for Different Types of Manure.
For more information about food safety and the environmental impacts of manure application see Manure nitrogen and Use manure responsibly.

pH requirements

The pH of a soil is a measure of its acidity. Soil pH affects nutrient availability and crop performance. Adjust pH to 6.5 on sandy soils and 6.0 on clay soils as recommended by a soil test report.

In established vineyards sample soil in the vine row every three years to ensure the pH is satisfactory. If pH is low or acidic, apply lime in the fall to the sod cover or before spring cultivation. The results will not show immediately because lime reacts slowly in the soil. Apply lime to established vineyards when the pH drops below 5.1 on clay loam soils or 5.6 on sandy soils. Lime raises the soil pH, reduces its acidity and also supplies calcium. For details regarding rates and suggested types of lime to use, refer to Soil pH and Liming.

Petiole Analysis for Grapes

In established plantings, the best way to determine the nutrient status of the vines is by petiole analysis. In conjunction with soil analysis, it provides good information for adjusting fertilizer rates. For more information on these tests, see Plant tissue analysis.

Nutrient uptake is affected by many vineyard conditions and varies slightly from year to year, depending on the season. To obtain optimum growth and fruit quality, all nutrients must be present in sufficient concentrations. See Table 6-1. Nutrient Sufficiency Range of Grape Petioles.

For petiole analysis to be most useful, sample the same vines each year. Use these tests along with soil testing to determine the fertilizer program. Soil management practices, vine age, rootstock, soil type, previous fertilizer, growth, fruit size, colour and storage quality must also be considered to determine fertilizer requirements.

Table 6-1. Nutrient Sufficiency Range of Grape Petioles (Taken in September from Mature Vines) (PDF 67 kb)

Variety	N%	P%	K*%	Ca%	Mg%	Fe(ppm)	B(ppm)	Zn(ppm)	Mn(ppm)
Vinifera	0.8-1.4	0.15-0.40	1.2-2.3	1.0-3.0	0.6-1.5	15-100	20-60	15-100	20-200
Fredonia	0.6-1.2	0.15-0.40	0.8-1.8	1.0-3.0	0.6-1.5	15-100	20-60	15-100	20-200
Other	0.7-1.3	0.15-0.40	1.0-2.0	1.0-3.0	0.6-1.5	15-100	20-60	15-100	20-200

* Potassium levels will be higher with grapes grown on sandy loam soils.

Fertilizer for Grapes

The best time to effectively incorporate nutrients such as potassium, phosphorous, boron and lime into the soil is prior to planting the vineyard. Nutrient levels in the topsoil adequate for vineyard establishment are 12-20 ppm phosphorus, 120-150 ppm potassium, 100-250 ppm magnesium and 1,000-5,000 ppm calcium. Table 6-2. Phosphorus and Potassium Soil Requirements for New Plantings of Grapes, provides fertilizer rates prior to planting. Along with incorporation of organic matter such as manure, these fertility levels will sustain the vineyard through the juvenile years.

On coarse-textured, infertile soils use a 10-52-10 or 20-20-20 starter solution at planting time.
High nitrogen levels can result in excessive growth and incomplete vine hardening. Use cover crops to reduce late season nitrogen levels in cultivated vineyards, especially in new plantings. Sow cover crops such as Italian ryegrass about July 1 to take up much of the available nitrogen in the soil.

Nitrogen (N)

Use petiole analysis to determine nitrogen requirements. Use 34 kg of nitrogen per ha only if this information is not available. Broadcast nitrogen before the first cultivation. In vineyards with sod between the rows, apply nitrogen as early as possible in the spring. Where urea (46-0-0) is applied, it must be incorporated to reduce losses by volatization. Do not use urea in vineyards with sod between the rows because incorporation is not possible. Reduce rates or eliminate nitrogen entirely if manure is used or growth has been excessive. If severe winter temperatures cause fruit bud damage, it may be necessary to split nitrogen applications. Apply the first application in mid-April, and the second application, if necessary, after bloom in late May. During dry springs, use irrigation to move the fertilizer into the rooting zone just before first bloom or immediately after petal fall. Consider foliar applications of nitrogen if vine performance and petiole analysis suggest the need.

Phosphorus (P)

Grapes do not require high levels of soil phosphorus. With a few exceptions, the level of phosphorus in Ontario soils is adequate for grapes. In established plantings, use plant analysis along with soil analysis to estimate phosphorus requirements. Phosphorus soil test values between 12-20 ppm are adequate for vineyard establishment and production. See Table 6-2. Phosphorus and Potassium Soil Requirements for New Plantings of Grapes,below. Apply phosphorus before planting and thoroughly incorporate it into the soil. Additional phosphorus may be needed for sod or cover crop maintenance.

Table 6-2a. Phosphorus Soil Requirements for New Plantings of Grapes* (PDF 71 kb)

Soil Test (ppm P)	Phosphates (P₂0₅) req'd kg/ha
0-3	80 HR
4-5	60 HR
6-7	50 HR
8-9	40 MR
10-12	20 MR
13-15	0 LR
16-20	0 LR
21-25	0 RR
26-30	0 RR
31-40	0 RR
41-50	0 RR
51-60	0 RR
61-80	0 NR
80 +	0 NR

* For new plantings, apply only every second year. For established grapes, use plant analysis to estimate requirements of N, P and K. HR, MR, LR, RR, and NR denote, respectively, high, medium, low, rare and no probabilities of profitable crop response to applied nutrient.

Potassium (K)

Grapes require larger amounts of potassium than tree fruits. In established plantings, use plant analysis along with soil analysis to estimate potassium to determine requirements. Excess potassium can lead to deficiency of magnesium (Mg). Avoid unnecessary potassium applications.

Prior to establishment, incorporate potassium according to Table 6-2. Phosphorus and Potassium Soil Requirements for New Plantings of Grapes, below. In established cultivated vineyards, broadcast potassium before the first cultivation in the spring. In established vineyards with sod between the rows, and in vineyards on clay soils, apply potassium in a band to reduce potassium fixation and increase its availability to the vines. Muriate of potash (0-0-60, potassium chloride) can injure roots and trunks if applied too closely to the trunk.

Table 6-2b. Potassium Soil Requirements for New Plantings of Grapes* (PDF 71 kb)

Soil Test (ppm K)	Potassium (K₂O) req'd kg/ha
0-15	270 HR
16-30	270 HR
31-45	270 HR
46-60	270 HR
61-80	270 HR
81-100	270 HR
101-120	270 HR
121-150	270 MR
151-180	270 MR
181-210	270 MR
211-250	270 LR
250 +	270 LR

Foliar application of potassium for grapes

In dry growing seasons, potassium is not readily available to the plant. When a potassium deficiency occurs, foliar applications of potassium may help. Foliar potassium applied at veraison (when grapes begin to ripen) may improve fruit yield and quality.

Magnesium (Mg)

Magnesium soil test values between 100-250 ppm are adequate for grapes. Dolomitic limestone can be used on acidic soils to raise the soil pH and to supply magnesium. Magnesium deficiency has become more evident in vineyards, particularly when high rates of potassium are used.

Magnesium deficiency can lead to premature fruit drop. Because magnesium is a part of the chlorophyll molecule, magnesium deficient vines have older leaves that are pale in colour. Petiole analysis is the best way to evaluate magnesium levels.

Foliar sprays correct magnesium deficiency for the current year only. For long-term corrections, apply magnesium to the soil in early spring. On some soil types a single, early-spring application of soil-applied magnesium may not be enough. A second or third application the next spring may be required before the magnesium level in the plant improves..

Foliar sprays are recommended for the first two years, in addition to soil applications. See Table 6-3. Magnesium Foliar Sprays.

Table 6-3. Magnesium Foliar Sprays(PDF 65 kb)

Timing	Product	Rate	Notes
3 sprays spaced 10 days apart beginning in mid July	Magnesium sulfate (Epsom salts)	20 kg/1,000 L water	Wet plant to point of runoff. Do not concentrate beyond 40 kg/1,000 L water.
3 sprays spaced 10 days apart beginning in mid July	Liquid formulations including chelates*	Consult product label	May be compatible with some pesticides. Consult product label.

*Use chelates recommended for foliar sprays.

Fruit or foliage injury may occur if pesticides are mixed with magnesium sulfate, so apply magnesium sulfate separately. Check the manufacturer's label about mixtures of magnesium chelates with pesticides. Use chelates recommended for foliar sprays.

Calcium (Ca)

Calcium deficiency has been associated with stem and bunch breakdown of Canada Muscat and Himrod grapes. If applied too close to harvest, some formulations of calcium chloride (CaCl₂) result in poor fruit finish.

Use CaCl₂ (77% flakes) at 4 kg/1,000 L of water from early July to mid-August. Apply sufficient volume of spray to wet the entire vine. Apply three sprays, 10-12 days apart. Do not concentrate sprays as foliage may be injured as a result. Calcium sprays must contact the fruit for uptake to be effective. Do not apply calcium formulations that contain nitrogen after the end of July or fruit quality may suffer.

When using calcium chelates, be sure they are recommended for foliar sprays. For all formulations, consult label directions for rates and compatibility with pesticides. The product used is not as important as the total amount of actual or elemental calcium applied. For example, calcium chloride (77% flakes) contains 28% actual calcium. For acceptable results up to 12 kg/ha of actual calcium is often required in a total of four or more sprays. Calcium sprays may damage foliage and fruit if applied during low temperatures and wet weather that delay the drying of the spray. Injury can also occur if calcium is applied in hot (over 25°C) or humid weather.

Micronutrients for Grapes

Deficiencies of micronutrients are not widespread in Ontario plantings. The desirable range for micronutrients is quite narrow. Micronutrients applied in excess can cause more damage than deficiencies. For this reason, do not apply micronutrients unless petiole analysis confirms a deficiency. Only apply the nutrient that is deficient and only in sufficient quantities to correct the problem.

Lime-induced chlorosis is a deficiency in iron or manganese occasionally induced by alkaline soils with high soil bicarbonates or by excessive lime application. For additional information, see Micronutrients.

Warning: Do not concentrate nutrient sprays. Do not spray at temperatures above 25°C.

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