Growing Grapescrop nutrition advice
Growing Grapescrop nutrition advice
Everything you need to know about Grape and vineyard fertiliser, best practice, suitable products, field trials and more.
Advice for growing grapes and vineyards(Vitis vinifera)
Soils: Grapevines can adapt to a wide range of soil types. If soil depth, texture, and water conditions are favourable, grapevines will survive and bear saleable crops in soils with poor fertility. Grapevines do require well-drained soil.
In soils with a high pH (above 7.5) deficiencies in phosphorus, but also iron and other micronutrients may appear.
If the soil is deep enough, grass can be implemented between the rows in order to prevent soil erosion and suppress weeds.
Site selection: Localised micro-climates play an important role in the feasibility of planting grapes at a specific site. The most important feature is cold air and drainage.
Other factors to consider for site selection are; availability of full sunlight and freedom from strong wind and heavy hail.
Grapes typically require a hot, dry climate, i.e., warm days, cool nights and low humidity. These generally produce higher-quality grapes.
The season at a particular site must be long enough to allow both the fruit and the vegetative parts of the vine to mature. It must provide enough heat to ripen the fruit and vegetation.
Winter must be long and cold enough to ensure a vines dormancy period. Late spring frosts present a threat to the young buds, as they are sensitive to freezing temperatures that can damage and destroy flower clusters.
There must be adequate sunlight hours to ensure adequate photosynthesis to supply sufficient carbohydrates to mature the fruit and vine.
Heavy or little rain during the ripening period may provoke various grape diseases.
Drip irrigation optimises the water supply for grape production. Drip irrigation is now the major irrigation method used in intensive growth environments, enabling longer production periods, better quality, and higher yields. However, it isn’t allowed in all territories, specifically when there is a protected geographical indication in the region.
Grapevines have fewer mineral deficiencies and a lower plant nutrient demand than many other horticultural crops.
Phosphorus, potassium, and lime applications should be based on the results of soil tests and leaf analysis.
Nitrogen fertiliser should be applied during periods of active N uptake to minimise loss through soil leaching. This includes the period from bud-break to veraison, and if leaf fall has not occurred, immediately after fruit harvest.
Multiple applications of nitrogen are preferred over one large spring application. Most nitrogen forms can be used equally in vineyards.
Dynamics of nutrient uptake in vineyards over a crop season
The following dynamics patterns can be seen above:
- N uptake is relatively low during the early season, it rises sharply until fruit-set, then decreases sharply until harvest, and then increases sharply again after harvest.
- P follows a similar pattern, but it only increases after harvest.
- K uptake rate starts higher than N and P, then falls steeply until harvest, before slightly recovering after harvest.
Role of nutrients
- Promotes high yields and ensures vegetative growth of the crop.
- Plays a key role in the synthesis of proteins which are directly involved in growth and yield.
- Promotes development of a good root system – a prerequisite for flowering and hence the overall number and maintenance of fruits.
- Essential for appropriate energy management in the plant. Enhances cell division.
- Enhances transport of sugars to the fruits. A cofactor of tens of enzymes. Regulates water management, mainly through stomata aperture.
- Enhances the sugar content of the fruit. Reduces susceptibility to many kinds of abiotic, and biotic, stresses. Improves deep green fruit colour, firm flesh, shape, and overall yields.
- Promotes cell-wall stability, providing the plant with a strong structure and resistance to diseases.
- Adequate calcium prevents blossom-end rot (BER). It also delivers improved shelf life.
- Is the central part of the chlorophyll molecule, playing a key role in photosynthesis. Increases Fe utilisation.
- Magnesium is the carrier of phosphorus in the plant. It is both an enzyme activator and a constituent of many enzymes. Adequate Mg application helps obtain a deep green fruit colour.
- Essential for proteins and chlorophyll synthesis. Iron is an important factor in many enzymes, associated with the energy transfer and the respiratory systems.
- Improves translocation of sugars and carbohydrates, pollination and seed production. Cell division and cell-wall formation are both related to Ca uptake and use.
- Zinc is required for the production of auxin, an essential growth hormone. Promotes proteins and chlorophyll synthesis. Necessary for starch formation and proper root development.
- Involved in the metabolism of N and carbohydrates. A catalyst in photosynthesis and respiration. Included in enzymes involved in building and converting amino acids to proteins.
- This nutrient is important for nitrate reductase activity, converting nitrates to amino acids. Conversion of inorganic P into organic forms.
|Nitrogen||• Mature leaves: uniformly small and light-green or yellow, throughout the vine.
• Shoot growth: slow and ceases in midsummer.
• Internodes: short.
• Fruit maturation: precocious.
• Fruit quality: poor, including poor colour in red varieties.
• Total N in bloom-time petiole: <1%; Nitrate-N in bloom-time petiole: <350 ppm.
|Phosphorous||• P-deficient plants have weak roots, are stunted, and produce small, dark green or brown leaves.
• Fruit-set is reduced, thus impairing production.
• Phosphorus deficiency is most common when soil pH is too low (<5.5) or too high (>7.0).
|Potassium||• Old leaves are the most sensitive to potassium deficiency exhibiting marginal chlorosis and, in severe cases, the leaf margins die.
• A dull dark green colour appears on the leaves. In mid- to late-summer leaves may have a bronze colour, especially on west-facing side of the trellis. Some leaves may develop dark spots or blotches.
• K-deficiency can be aggravated by the application of dolomitic limestone, which is applied to raise the pH and enrich the soil with Mg.
• Severe K deficiency markedly reduces vine vigour, berry size, and crop yield.
|Magnesium||• Yellowing of older leaves, beginning between the major veins, which retain a narrow green border. This interveinal chlorosis shows first as scattered blotches. Younger leaves are less affected. It does not become evident until late summer unless the deficiency is severe.
• Young terminal leaves may never show symptoms unless the entire vine is extremely affected.
• Yields are reduced.
• Mg deficiency can reduce yield and delay ripening if leaf chlorosis becomes severe enough to inhibit photosynthesis.
• Deficiency is revealed mainly in plots with pH<5.5, and plots that have received high N, Ca, or K fertiliser rates, on light soils and in very dry years.
Ref. Dami et al., Ohio, 2005
|Iron||• Pale interveinal yellowing appears on younger leaves first. All other leaves remain dark green.
• Reduction in shoot growth and yield.
• Iron-deficient plants are yellow and stunted.
• Most often observed when growing in alkaline (pH > 7.0) or calcareous soils, and can be also induced by over-liming, poor drainage, or high concentrations of metallic ions in the soil or nutrient solution.
|Manganese||• The symptoms appear in mid-to-late summer, as an interveinal chlorosis, or yellowing of the basal leaves.
• Since Mn deficiency only affects the less photosynthetically-active older leaves, yield losses from Mn deficiency are rarely a concern.
• Mn deficiency occurs on pH>7 soils, and on sandy-, calcareous- , or excessively limed soils.
|Molybdenum||• Older leaves are affected first, as a whitish-tan interveinal chlorosis, accompanied by marginal leaf burn in severe cases, followed by death of the tissue at the margins.
• Plants severely stunted.
|Zinc||• Young leaves appear yellowed and tend to be smaller in size.
• Interveinal yellowing similar to that provoked by Fe deficiency.
• New growth is adversely affected with shorter internodes that produce stunted shoots.
• Older leaves initially show yellowish-green interveinal chlorosis, developing later to yellow/whitish. The veins keep their green margins.
• Much fewer flowers, which may be infertile.
• Withered clusters with tiny, under-ripe fruit.
Apply nitrogen within 30-60 cm of the vine by banding + immediate disking, or by fertigation. If nitrogen fertilisation is needed, an annual application of 35-60 kg/ha of nitrogen, on sandy loam soils, is a good starting point for mature vineyards. Young vineyards (in their 1st and 2nd growing seasons) in need of nitrogen fertilisation typically require no more than 30 kg/ha of nitrogen.
Fertigation by drip irrigation in open fields and protected management
As drip irrigation is so common with this crop, fertilisation is generally done by fertigation using fully-soluble fertilisers. The N-P-K-Ca-Mg ratios should be adapted according to the crops’ needs at every growth stage.
A properly applied foliar spray program usually focuses on micronutrients and can be beneficial. Before applying any nutrient spray, laboratory petiole analysis from affected and normal leaves as well as soil analysis should be performed. This will help make an informed decision, with more evidence than just visual symptoms. Zinc deficiency may be corrected by applying a foliar spray 2-3 weeks before bloom. As iron (Fe) is immobile in plants, spray only existing foliage. If chlorosis is severe and persists, repeated applications at 10-20-day intervals may be necessary.