Nutrition

Soil Management

The Ministry of Agriculture and Lands has produced several reference publications that will assist people in the management of soils. These publications are called Soil Management Handbook for the Lower Fraser Valley and Soil Management Handbook for the Okanagan and Similkameen Valleys.

These handbooks complement the soil descriptions contained in Ministry of Environment (MOE) Technical Report #18 Soils of the Okanagan and Similkameen Valleys and Soils of the LangleyVancouver Map Area RAB Bulletin 18 (Vol. 1-5). For the Vancouver Island area, MOE Technical report #15 Soils of Southeast Vancouver Island Duncan-Nanaimo Area. These maps are no longer available to the public, but may be available from some Ministry of Agriculture and Lands offices.

Soils most suitable for commercial grape production have the following characteristics: 

  • well drained
  • no ground water within 2 metres of the surface
  • no restriction to root development
  • pH of 6 to 7.5 in the top 40 cm
  • nil to slight calcariousness in the top 40 cm and slight to moderate calcariousness beyond 40 cm
  • non saline
  • preferably medium to high cation exchange capacity
  • medium to warm soil temperature
  • site which has a slight slope (3 to 4%) to the south or southwest. 
  • are mineral soils with a minimum of 1% organic matter or more in interior soils and 4% or more organic matter in coastal soils 

Soils differ greatly in the proportions of organic matter, clay, silt, sand, and rock; water holding ability; bacterial and other animal life. Soils change with time. Farmed soils can change rapidly. Good soil management promotes grape production by encouraging a favourable environment for grape roots. All vineyard practices that involve the soil will affect plant growth in some way.

Soil Texture

Soil texture is an important property affecting vine growth and soil management. Soil texture refers to the combination of mineral particle sizes in the soil. A soil can be coarse, medium, or fine textured; each is dependent upon the combination of the individual mineral particle sizes which are grouped into four particle sizes as follows:

  1. Gravel – size 2 mm to 80 mm, generally rounded and loosely compacted;
  2. Sand – size 0.05 mm to 2 mm, sub-rounded primarily quartz or feldspar minerals;
  3. Silt – size 0.002 mm to 0.05 mm, rounded and not sticky when moist or wet; and,
  4. Clay – size <0.002 mm, flat secondary minerals, sticky and plastic when wet or moist. 

Most soils are mixtures of these four particle sizes and in addition, some also contain organic matter. 

Individual soil texture classes are placed into five main soil textural groups. Common properties related to each group are found in the following table. 

For additional reading: Parnes, R. (1990). Fertile Soil: A Grower’s Guide to Organic and Inorganic Fertilizers. Davis, California

Table 4.2 – Main Characteristics of Soil Textural Groups 

Textural Group  Soil Textures  Characteristics 
Coarse  gravels (G) sand(S) loamy sand (LS)  Generally single grained loose and very friable when moist, loose and soft when dry; many large pores; very low water holding capacity; and rapid perviousness; loose sands tend to wind blow; good bearing strength and trafficability when moist.
Moderately Coarse  sand loam (SL)  Very friable when moist, moderate to low water holding capacity; good trafficability and bearing strength when moist.
Medium loam (L) silt loam (SiL) silt (Si)  Friable when moist; slightly sticky and plastic when wet; many medium to small pores; high water holding capacity; moderately good trafficability and bearing strength when moist.
Moderately Fine  clay loam (CL) silty clay loam (SiCL) sandy clay loam (SCL)  Hard to very hard when dry; sticky and plastic when wet; friable to firm when moist; high proportion of small pores; high water holding capacity; poor trafficability when wet
Fine silty clay (SiC) sandy clay (SC) clay (C) heavy clay (HC) Very hard when dry; very sticky and plastic when wet; firm when moist; many small pores; moderately high water holding capacity; very poor trafficability when wet. 

 

Available Water Storage Capacity (AWSC) Affected by Soil Texture 

The capacity of a soil to store water depends upon the particle size composition of the soil (texture) and the soil particle arrangement (structure). It is also dependent upon organic matter and content of coarse fragments.

The available water in soils is generally considered as that held between field capacity and the wilting coefficient. Below are typical moisture holding capacities of different soil textures. 

Table 4.3 – AWSC Values for Soil Textures in the Okanagan and Similkameen Valleys 

Texture Class AWSC* mm/cm of Soil  Relative AWSC Rating
Gravel 0.2 – 0.6 Very low
Sand  0.8 Very low
Loamy Sand 1.0 Low
Sandy Loam 1.2  Moderate 
Loam  1.7 Moderate
Silt Loam  2.1 High 
Clay Loam 2.0  High 
Clay 2.0  High 
Organic  2.5  Very high 
* AWSC values are given for the less than 2 mm size fraction only. For gravelly soils with coarse fragments, the AWSC values are correspondingly reduced. Also the whole profile water holding capacity is much less on shallow soils. 

In the soil texture triangle, pure sand (S), silt (Si) and clay (C) soils are shown near the triangle corners while soil textures of loam (L) or clay loam (CL) near the centre have various amounts of each.

Figure 4.8 – The Composition of Textural Groups. 

Percentage of clay and sand in the main textural classes of soils; the remainder of each class is silt

The texture classes of the soil are: Sand (S), heavy clay (HC), silt (Si), Loam (L), or combinations of various forms as silt loam (SiL) The symbols within the triangle are meant to group these classes into similar coarseness classes from fine to coarse. 

Good Soil Management

Before planting a vineyard: 

  1. Disturb the soil as little as possible during land clearing except in cases where shallow soils overlay clay or silt soils or where clay or silt soils overlay sands or gravels.
  2. Have the soil analyzed at depths of 0-20 cm and 20 to 40 cm.
  3. Incorporate large amounts of organic matter or grow a (deep rooted) green manure crop (e.g. fall rye) for several years before planting.
  4. As grapes are a deep rooted crop, incorporate any recommended nutrients, lime, organic matter etc., as deep as possible.
  5. Before planting, break up any hard pan with a deep ripper at least in the location where vines will be planted. It is better to use two way and close spacings in the ripping operation. Organic matter could be dropped into the trench created by the slip plow during this operation so that the organic matter and any soil amendments are placed deep into the soil profile. 

After Planting a Vineyard — Good Management Should

  1. Provide adequate amounts of water and plant nutrients for optimum crop growth.
  2. Avoid excessive uptake of nitrogen, particularly late in the season, thereby promoting winter hardiness.
  3. Prevent soil erosion, by wind or water through the use of temporary cover crops planted in the late summer and incorporated in the spring or through the use of permanent cover crops.
  4. Improve or maintain soil structure.
  5. Extend root development.
  6. Increase or maintain soil organic matter.
  7. Avoid working on wet soils, especially clay or silt soils.
  8. Keep the number of tractor trips in the vineyard with wet to moist soil to a minimum to avoid soil compaction. (compact soil has a bulk density greater than 1.4).
  9. Maintain a cover crop on alternate rows in clean cultivated vineyards with heavy soils for tractor traffic. 9. Plant deep rooted cover crops to keep the soil open.

Poor Soil Management Will Result In 

  1. Decreased soil air content and water infiltration rates (e.g. by frequent, deep cultivations).
  2. Decreased soil organic matter levels (e.g. by not growing cover crops or adding organic matter to the soil). 

Erosion Control 

Water and wind erosion should be reduced or eliminated. Water erosion damage is most severe on slopes where grapes are grown up and down the slope. Wind erosion is severe when light sandy soils are left bare.

Winter cover crops, permanent grass, and drainage systems all help to reduce erosion. The use of fall seeded cover crops can provide good water and wind erosion control. Wind erosion in the summer months on sandy soils can be reduced through the use of summer cover crops. 

Organic Matter

Soil organic matter is a very small part of a mineral soil, but plays a very important role. Proper management of the organic matter influences the vineyard long term productivity. About 40% to 45% of the soil organic matter is very stable and resists decomposition. Another 40% to 45% is moderately stable (half life of 20 to 40 years). This portion is held within the soil particles and is very important to soil fertility accounting for 40% to 50% of the nutrients released each year. The remaining 10% to 15% decomposes easily and is composed of living and dead organisms (bacteria, algae, fungi, earthworms, nematodes etc.). 

Excessive tillage, soil erosion and poor cover crop management will speed the loss of organic matter, especially in the interior where irrigation and cultivation, combined with hot summers, “burns” the organic matter very quickly. 

In addition to the inorganic fertilizers available, there are organic fertilizers that can be used with advantage in vineyards. Some of these are listed in Table 4.2. There are several considerations that must be made when dealing with organic fertilizers. These are:

  • the nutrients they contain are usually in an insoluble form (except potassium) and must be broken down by soil microorganisms. Organic fertilizers are therefore more effective if they are incorporated into the soil 
  • organic fertilizers are usually bulky and expensive to transport. The use of green manure crops and cultivating these into the soil may be a good substitute for some forms of organic fertilizer. 

Organic matter improves the physical condition of the soil, increases soil moisture-holding capacity, improves aeration and serves as a source of nitrogen and other plant food. It supports bacteria and fungi which aid in the release of plant nutrients.

Most vineyard soils are low in organic matter. The organic matter level can be increased through the addition of green manure crops, barnyard manure, grape prunings, manure, and hay. Maintaining or improving soil organic matter will benefit the soil and grape plants. 

Methods of Improving Soil Organic Matter

(1) Green Mature Crops

Organic residues from green manure crops maintain the soil in a more desirable physical condition, helping water and air movement into the soil.

Green manure crops provide a source of nitrogen that is released slowly throughout the growing season. 

Green manure crops can be planted in March or April, after the fall cover has been removed. It will mature in two months. It can then be incorporated and the vineyard prepared for the fall cover crop that is planted at the end of July. A green manure crop of oats, Austrian winter peas and vetch at 78, 45 and 22 kg/ha, respectively, or clover at 15 to 20 kg/ha in combination with cereals such as barley and oats will enrich the soil with nitrogen and organic matter when they are turned under.

A temporary nitrogen deficiency may occur for a short time after ploughing in more mature green manure crops. 

Grape pomace composed of seeds, skins and stems can be used as a source of organic matter. Pomace is usually quite acid. On heavy soils it may help to improve soil pH and structure. Do not use rates over 3 tonnes/ha. 

Grape prunings are a cheap source of organic matter. Mulching these with a rotary mower, followed by incorporation into the soil, will provide more than a tonne of organic matter per hectare in most vineyards.

(2) Temporary Cover Crops

All vineyards, regardless of age, should have some form of cover crop during the period of August 1 to April 1. Cover crops, if properly managed, will add much-needed organic matter to the soil, reduce soil erosion, hasten fruit and vine maturity, improve water penetration during the fall and winter, and provide winter protection to the roots.

Fall cover crops should be planted up to the trunk of the vines for the greatest benefit.

Fertilizers to aid in cover crop establishment should be applied only if the cover crop is to be a permanent one. 

Adequate soil moisture is needed for good seed germination and cover crop growth.

Spring cereals such as barley and oats or winter cereals such as winter wheat or fall rye should be seeded at 100 to 170 kg/ha.

Temporary cover crops should be turned under while still green. If the growth is too mature, vine growth can be reduced and soil nutrients tied up for three to five years before being released with decomposition. Apply 75 to 100 kg/ha of 34- 0-0 to a heavy cover crop just before working it under to aid decomposition

Temporary cover crops should be planted by the end of July.

(3) Application of Manures

The positive results of manure applications to vineyards have in most cases, been greater than the addition of the plant nutrients contained in the manure would warrant. Manures help to improve soil organic matter, soil structure and nutrition. There are also other beneficial effects when manures are added to soil.

Manures should be added to vineyards before working the soil in the spring. The next best time is in the fall, before the soil freezes. 

Cow and poultry manures are commonly used. Each type differs in nutrient content. Manures supply plant food over a period time, but in the year of application each ton of manure should supply approximately the amount shown in Table 4.2. Recommended rates of N, P2O5, and K2O can be adjusted downward, depending upon the amount of manure applied. 

Some chemical fertilizers should be used, even when heavy applications of manure are made.

Cow manure may be applied up to 35 tonnes per hectare. Poultry manure may be applied up to 15 tonnes per hectare.

Table 4.4 Fertilizer value of cow and poultry manure 

Kilograms per tonne of manure 
Type of manure  Quality  P2O5  K2O 
Cow manure 

Good

Poor

2.5 

1.5 

0.5 

Poultry manure 

Good

Poor 

5

2

4

3

Good quality refers to properly stored manure, containing little litter. Poor quality refers to exposed, leached manure with considerable litter.

Non-Nutritional Causes of Low Vine Vigour

Grape vines that do not produce enough leaf area to fill the trellis are not capable of producing optimum yields of grapes. Such plants have a scarcity of leaf area. The vigour of such plants needs to be improved. Usually there are factors other than nutrition at work. Some of these factors are listed in

Fertilizers and Mineral Elements Plant Nutrients

Present information shows that 16 elements are essential to good plant nutrition. Three of these – carbon, hydrogen and oxygen – are taken from air and water. The other 13 are normally absorbed from soil by roots. Nitrogen, phosphorus, potassium, calcium, magnesium and sulphur are required in larger amounts, and are therefore called major nutrients. Zinc, iron, manganese, copper, boron, molybdenum and chlorine are required in small amounts, and therefore called micro nutrients. 

 

Table 4.5 Causes and possible remedies of low vigour

 

Cause of Low Vigour Possible remedy
Shallow or deep, dry soils   Add more organic matter to the soil, improve irrigation
Overcropping  Balance pruning and/or bunch thinning 
Root injury caused by deep cultivation Shallow cultivation
Winter injury to the roots  Replant
Poorly drained soil drain soil  Reduce irrigation, shallow cultivation
Insects and disease  See appropriate sections of the guide
Low or high pH  Apply lime or sulfur products according to soil test recommendations
Herbicide injury  Reduce rates, trim vine tips near the ground, change to a safer herbicide, do not spray on vine trunks until pruning or suckering wounds have healed 

In the interior alkaline soils there is a reduced availability of manganese, iron, copper and zinc. Alkaline soils that are also sodic will express very high levels of sodium in addition to the low availability of manganese, iron, copper and zinc. In the coastal acid soils there is an increased availability of aluminum and manganese, and these elements together with copper may become toxic. Aluminum toxicity causes severe stunting of roots which become short and stubby, relatively unbranched and dark coloured, relative to well branched roots in good soils. The availability of most nutrients is reduced at low pH. Calcium and boron may be in short supply in acid soils. A boron deficiency causes root distortion, and death of root tips. Growth is restored when the availability of boron is restored.

Carbon is obtained from carbon dioxide in the air. Hydrogen and oxygen are supplied mainly by water. These nutrients are used to build parts of the vine. 

They are also the major source of energy for growth. 

 

Table 4.6 Nutrients essential to plant growth 

Major Elements  Secondary Element  Micro Elements
Carbon   Boron
Hydrogen Magnesium Zinc
Nitrogen Calcium Copper
Oxygen Iron Manganese
Phosphorous Sulphur Molybdenum
Potassium   Chlorine

 

 

Table 4.7 Usual visual expressions of nutrition disorders 

Elements Seasonal Appearance Shout Position 
Boron Early Apical
Zinc Early Apical-mid
Iron Early Apical-mid
Manganese Mid-season Basal
Magnesium Late Basal
Potassium Mid-late Basal
Nitrogen   Not diagnostic

The following descriptions of nutrients and some of the symptoms of nutrient deficiencies provide some guidance for diagnosing plant nutrient needs. These are only a guide and should be confirmed by chemical analysis.

 

Table 4.8 Nutritional deficiencies

Common  Less Common  Not Observed 
Boron Manganese Chloride
Nitrogen Phosphorous Sulphur
Potassium Magnesium Copper
Zinc Iron Molybdenum
  Calcium  

 

Table 4.9 Nutritional excesses

Common Not Observed 
Boron Calcium
Nitrogen

Chloride

Copper 

Iron

Magnesium

Manganese

Molybdenum

Phosphorous

Sulphur

 

Nitrogen

Nitrogen is the most widely used, and most difficult nutrient to manage, in vineyards. Plants use nitrogen to form proteins that make up the protoplasm, the living substance in plant cells.

Grapes, compared to many other crops, have a low nitrogen requirement. Shortages of nitrogen are not detected easily. Generally, fruit yields are reduced before visual symptoms such as stunted growth, thin shoots, or pale green leaves are seen. Reduced fruit bud development, resulting in lower yields, can be caused either by excess or deficient nitrogen levels. 

Basic nitrogen fertilizer recommendations are difficult to provide because vine growth is also largely affected by soil type, the rate of breakdown of organic matter (mineralization), vigour of a variety, irrigation practices and conditions of the root system. Generally, sandy soils require frequent small nitrogen applications while loamy, silt or clay soils may not require any fertilizer. Vigour in newly planted vineyards will be influenced by the previous cropping history of the land. 

Excess Nitrogen 

Excess nitrogen stimulates vegetative growth and may delay wood maturity. Excess nitrogen may also create shading conditions which contribute to lower bud fruitfulness and increased powdery mildew and Botrytis. 

Nitrogen vs. Cold Hardiness

It is not true that applications of nitrogen will reduce cold hardiness of vines. Vines low in vigour and low in production as a result of nitrogen deficiency need applications of nitrogen to become more vigorous and more productive. Excess vigour as a result of excess nitrogen leads to succulent growth and poor wood maturity which in turn is not winter hardy.

Nitrogen Soil Application

Established Plantings

A restricted nitrogen program may be necessary to reduce vigour, hasten fruit maturity, and promote winter hardiness. Vine growth and yields are often adequate without application of nitrogen fertilizer.

Efficient Fertilizer Use In Vineyards

The most efficient use of nitrogen fertilizer occurs if it is applied after bloom but before veraison. Early maturing varieties may have three or four weeks of time after harvest before leaf fall and may benefit from nitrogen after harvest, provided this does not stimulate new growth. 

The availability of nitrogen varies with the type of fertilizer used. Urea for example takes a long time to become available in a cool, wet soil. Local research has shown that nitrate based fertilizers such as calcium nitrate provide nitrogen almost immediately and provide soil solution nitrate for a limited time. Ammonium based fertilizer such as ammonium sulphate required almost 30 days before it became available and then persisted in the soil solution for a longer period of time depending on soil type and irrigation or rainfall. Timing of fertilizer applications to influence specific responses at specific times of the vegetative growth or at fruit formation is therefore more controllable with nitrate based fertilizers. The longer lasting ammonium based fertilizers must also therefore be used with caution late in the season when winter hardiness of the grape vine is of concern. 

The splitting of nitrate based fertilizers during the growing season will provide better control of the soil solution nitrate than large applications of fertilizers applied all at once. Slow release N formulations can also be used to apply nitrogen over a longer period of time. 

The concentration of the soil nitrogen solution is also affected by the frequency and duration of irrigation or rainfall. 

It takes about 3.7 kg of pure nitrogen to produce one ton of fresh grapes, with 1.6 kg stored in the clusters and 2.1 kg in the vegetative growth. This ratio of nitrogen storage holds true for all varieties, regardless of age. Nitrogen needs can therefore be calculated for a four or five ton grape crop if there is no breakdown of organic matter in the soil (mineralization).

A crop of four tons of grapes would therefore require (3.7 x 4) = 14.8kg of actual N. However, a process called mineralization releases plant nutrients including ammonia. Ammonia is quickly converted to a nitrogen source for plants, depending on soil oxygen content, soil temperature, soil moisture and soil pH. It is therefore difficult to calculate precisely how many kg of nitrogen it would take to produce the four-ton grape crop. 

Nitrogen Foliar Applications (Urea)

Foliar applications of urea are not generally recommended. However, they can be used under special circumstances when additional nitrogen is required. To avoid the delay of wood maturity, do not apply foliar nitrogen after the end of July. Some urea products contain an impurity called biuret. Foliar injury can result if the biuret content of urea exceeds 2 percent.

Nitrogen Fertilization at Related to Soil pH

Urea is an excellent source of nitrogen for plants when utilized on soils that have a pH of 7.0 or less. However, on soils with a higher pH, it may not be the most efficient N-source when surface applied because N-losses through ammonia volatilization are likely to be quite high. On alkaline soils (those having a pH higher than 7.0), ammonium sulfate (21-0-0) or ammonium nitrate (34-0-0) will have lower ammonium volatilization, and calcium nitrate will not have any. The first two fertilizers will acidify soils under irrigated conditions. The actual acidification rate depends on the physical and chemical properties of the soil as well as on the level of water percolating through the soil and the amount of fertilizer applied in excess of that used by plants. However, ammonium sulphate also contains 24°C, plant available sulphur which may be advantageous on soils containing insufficient levels. 

The preferred sources of nitrogen fertilizer on acid soils in decreasing order of their effect on soil pH are calcium nitrate, urea, ammonium nitrate and a mixture of ammonium sulphate and urea sold as 34- 0-0-11 on soils poorly supplied with plant available sulphur. Ammonium sulphate should probably be avoided on these soils except when correcting a sulphur deficiency or to reduce high pH.

 

Table 4.10 Amount of fertilizer needed to supply various amounts of nitrogen in kilograms per hectare

Actual Nitrogen Kg/ha  Urea 46-0-0  Ammonium nitrate 34-0-0  Ammonium sulphate 21-0-0 Calcium * nitrate 15-0-0
30  65  88  142  200
40  87 118 190 267
* Calcium Nitrate may be applied to the soil where the pH is low. It tends to maintain pH levels whereas other nitrogen fertilizers lower the pH. 

Assessing Nitrogen Needs

There is no single method that serves well as a guide to nitrogen requirements for grape vines. Nitrogen needs are determined during the growing season, and through the use of indicators such as crop load, amount of winter pruning, assessing canopies and by checking bloom time petiole analysis. In addition there are visual symptoms.

Calculation of Fertilizer Rate for Ground Applied Fertilizers

Fertilizers are labeled according to the percentage of nitrogen (N), phosphate (P2 O5) and potassium (K2O) and other nutrients when these are present. The rest of the ingredients in the fertilizer are carriers such as oxygen and hydrogen.

General Formula:

Phosphorus and Potassium

The application of P and K should be based on soil test recommendations.

Unnecessary soil applications of potassium may interfere with the uptake of calcium and magnesium. It is important to monitor soil potassium values and to carefully control potash fertilizer applications on low magnesium soils.

Phosphorus

The major role of phosphorus in plants is for energy transfer. Phosphate influences root, flower, seed and fruit formation. Deficiencies can result in stunted growth, small leaves, poor fruit set and a generally weak plant condition. Deficiencies are corrected with phosphate fertilization. The availability is also improved by maintaining soil pH in the optimal range (6 to 7.5). On acid soils (low pH), phosphorus combines with aluminum and iron to form insoluble compounds. 

Potassium

Potassium is needed to form sugars and starches, proteins, acids and colouring materials, odour and taste of grapes and wine. Potassium also increases plant winter hardiness, and drought resistance. Foliar symptoms of potassium deficiency usually occur in mid summer. Leaves in the centre of the new shoots develop yellowing or a lighter green. This starts at the leaf edge and gradually moves to the centre of the leaf. Brown spots and dead areas may develop. The spots may fall out and leave holes in the leaves. Leaves may become brittle. Fruit ripens unevenly. In cases of advanced deficiency, the leaves have a scorched appearance and may turn black. Shoot growth is reduced, vine vigour is low, and berry set and yields are also low in severe cases. Excess amounts of potassium will result in decreased uptake of calcium and magnesium and increased pH values in grape juice.

Magnesium

Magnesium is a major part of chlorophyll, the green material in leaves. Magnesium is also involved with phosphate uptake and movement in the vine. Deficiencies are sometimes related to land leveling operations, exposing soils containing either low magnesium or high potassium levels. Grape stem drying may be caused by magnesium deficiency. 

Soils with low magnesium values require magnesium applications. Dolomitic limestone is an effective means to supply soil applied magnesium if low pH values are present. Magnesium sulfate or Sul-Po-Mag can be used if pH values are above pH 6.5. 

Most vineyards require multiple sprays to maintain adequate magnesium levels to a maximum of 36Kg/ ha. Magnesium sprays can be combined with sprays of boron, zinc chelate or urea. 

Symptoms of magnesium deficiency in green fruited varieties begin with a yellowing of basal leaves that gradually progresses to younger leaves. The yellowing begins at the leaf edge and gradually moves into the leaf between the veins. Yellow areas eventually turn white and die. Browning of the leaves may eventually occur. In red fruited varieties the discolouration pattern is the same, except that the leaf becomes red or purple. In both the green and the red fruited varieties, the veins remain green. The leaves will drop prematurely in very severe cases. High calcium supplies relative to magnesium may induce magnesium deficiencies. Deficiency symptoms may be induced by low magnesium and/or high potassium levels in the soil and/or high nitrogen uptake by the roots.

Table 4.11 Fertilizer sources of sulphur and magnesium

Formulation  % sulphur % magnesium 
Sulphur products 90 0
Sul-Po-Mag 22 11
Gypsum 18 0
Espsom salts 18 10
13-16-10 13 0
16-20-10 14 0
21-0-0- 24 0
Dolomic limestone 0 0

 

Boron

Boron influences cell differentiation, cell growth, pollen germination and growth of pollen tubes.

Vineyards require regular soil applications of boron.

Boron uptake is related to soil moisture during the growing period. Drought induced boron deficiency is not uncommon during the spring growing period if vineyard soil moisture was inadequate the preceding fall. Where soil applications have been overlooked, a temporary restoration of boron levels may be obtained with one or more foliar applications, especially when poor set is anticipated. 

Soluble boron sprays may be combined with some pesticides such as wettable powders but not with oils or liquid pesticides. Soluble boron products may be added to herbicide tanks (check labels) and then sprayed onto weeds and soil. Avoid spraying vine trunks with this mixture due to the toxic effects of boron in this mixture to grape vines. Boron can be combined with other elements such as zinc chelate, magnesium or urea.

Petiole and soil tests provide a useful guide to boron requirements. 

Too much boron is very toxic to grape plants. Do not exceed recommended rates. Soil applications should be broadcast evenly over the entire vineyard area and should not be made within one month of lime applications. 

Symptoms of boron deficiency

Symptoms of boron deficiency may be noticeable on the fruit clusters, shoots or leaves, and may occur at different times of the year. Drought induced deficiency may be present if new leaves are small, misshapened, cupped, puckered, wrinkled and, sometimes, have missing lobes. Terminal buds stay dormant. Numerous lateral shoots appear. Shoots may be stunted and dwarfed after bud break with zigzag growth and more than normal lateral growth. Flowers and flower clusters may dry up. Some small round berries may appear mixed with normal sized berries. Later in the year, leaves may have interveinal yellowing or the yellowing may appear in patches. Internodes on new shoots may become shorter during the growing season, followed by dying of shoot tips and development of swollen areas that become corky and split. Severe cases of boron deficiency result in no new shoot growth or failure of flowers to set.

Soils where boron deficiencies are likely to occur

  1. Soils which are leached
  2. Soils low in phosphates
  3. Soils high in potassium or heavily limed soils
  4. Sandy or gravely soils
  5. High pH soils 

Table 4.12 Percentage equivalents and conversion factors for some plant food boron materials

Amount of material required to supply 1 kg boron/hectare
Kind of boron product content % boron content kg product required
Borate 40  12.5% 8.0 
Solubor 20% 20.0

Calcium

Calcium influences good root formation, protein formation and carbohydrate production. Calcium is used to build cell walls and helps “cement” cells together. Calcium controls the uptake of water, alters the availability of nutrients and prevents the toxic effects of others. A deficiency may produce young leaves that are distorted and small with irregular leaf margins. Leaves may turning yellow between the veins and at the leaf margins, followed by the appearance of pinhead sized spots near the leaf margins. Vine tips die. There appears to be a sensitive balance between calcium, magnesium, potassium and boron. An imbalance causes abnormal performance of plant functions. A lack of calcium is associated with berry shrivel and drying and brittleness of stems. Soil calcium levels are maintained by liming soils to the recommended pH. 

Soils in which a calcium deficiency may occur

  1. Acid soils
  2. Sandy soils, especially in coastal areas
  3. Soils which are subject to leaching through excessive irrigation or rain
  4. Soils which have accumulations of excessive amounts of potassium as a result of potassium applications when they are not needed, or continued use of high rates of manures.
  5. High nitrogen or potassium applications to a range of soils may contribute to calcium deficiency.
  6. Foliar application of Calcium can be used to correct Ca deficiency.

Zinc

Zinc influences berry set, pollen development, normal leaf development, the elongation of internodes, starch and chloroplasts. 

Zinc should be applied when zinc levels are low. Use both foliar symptoms and petiole tests to determine zinc levels. Zinc may be combined with sprays of boron, magnesium or urea.

The principal symptoms of zinc deficiency (Little Leaf) are a failure of shoots to grow normally, small and chlorotic leaves, straggly clusters, a widened angle formed by the two basal lobes of the leaf blade where the leaf stem or petiole is attached and a lightening or green colour between the veins of the leaf.

Vines grafted onto some rootstocks such as Freedom, Harmony and C-1613 are more susceptible to zinc deficiency.

Types of soils where zinc deficiencies commonly occur

  1. Acid soils that are leached, sandy or where total zinc is low
  2. Alkaline soils with a high pH
  3. Old corral sites
  4. Land that has been levelled (95 % of available zinc is in the top 15 cm or soil).
  5. Soils which are over limed
  6. Soils that are very low or very high in organic matter (muck soils)
  7. Cold wet springs
  8. Soils with excess phosphorous 

Zinc Fertilization of Soils

Generally, zinc is more available to plants in acid than in alkaline soils. However, zinc deficiencies do not occur on all alkaline soils and are observed quite often in acid soils. Zinc is a relatively immobile nutrient in soils and therefore should not be expected to move rapidly through the profile. It is advised that soil levels be determined before planting when an addition can still be easily worked into the root zone. When soil test values are 1 ug/mL (1 ppm) or less, it is recommended that 10 kg Zn be applied per hectare (about 30 kg/ha of zinc sulphate monohydrate (35% Zn) or 45 kg/ha of zinc sulphate heptahydrate (23% Zn). Such an application to the root zone will correct a zinc deficiency for a period of two to three years. 

Soil applications of zinc are expensive and are not always successful because zinc is easily tied up in the soil. Soil applications in existing vineyards should be applied only in localized, severely deficient areas. 

Foliar applications of zinc are more economical and effective. 

Table 4.13 Fertilizer sources of zinc

Formulation % Zinc
Zinc sulphate (monohydrate 35
Zinc sulphate (heptahydrate 23
Zinc 50 “neutral zinc 5
Zinc chelate 14

 

Iron

Iron is needed for development of chlorophyll, activation of enzyme systems and the formation of complex organic compounds.

Iron deficiency develops first on young leaves. Leaves develop yellowing between the veins, progressing to small veins and gradually to the main veins until the entire leaf is yellow. These symptoms are more pronounced than those of zinc or manganese deficiency. Yellow leaves eventually die.

Iron chlorosis, also known as lime induced iron deficiency, usually occurs on seepage sites and in grape varieties sensitive to high pH soils. Grape rootstocks listed under Phylloxera Control will aid in minimizing lime-induced iron deficiencies in scion varieties. Foliage of iron deficient plants may be made green by foliar application of iron chelates. This is a temporary measure and does not correct the basic cause. Iron sprays may have to be repeated several times to see results. Do not combine iron with other pesticides or minerals.

Soils Where Iron Deficiencies are Likely to Occur

  1. Soils with high pH and free calcium carbonates
  2. Poorly drained soils (poor soil aeration)
  3. Soils very high in manganese
  4. Oxygen deficient soils (compact soils)
  5. Soils with low or very high temperatures
  6. Land that has been leveled or where erosion occurs
  7. Where high phosphate applications have been made.
  8. Iron is not normally applied to the soil. See table for foliar application rates.

Manganese

Manganese assists in the formation of chlorophyll and activates enzymes.

Deficiency symptoms begin on basal leaves as a yellowing between veins. Manganese deficiencies are easily confused with iron or zinc deficiencies. Petiole analysis will help to separate these deficiencies. 

Deficiencies of manganese are possible in soils with pH values above seven. Manganese deficiencies sometimes occur with iron deficiencies. See foliar tables for materials and rates.

Copper

Copper is an important part of several plant enzymes and is involved in photosynthesis and chlorophyll formation. Copper influences leaf shape, size and colour, fruit set and yield, root growth and terminal growth. Copper will enhance the flavour, storage and shipping of some fruits and vegetables as well as increase their sugar content. Failure of flowers to set and seed to form are symptoms of copper deficiency in some annual crops.

Deficiency symptoms for copper would most likely occur on soils high in organic matter. Deficiency symptoms include poor root development, small pale leaves with burnt tips and margins, downward cupped leaves, rough bark on canes, petioles and veins, wilt and death of shoot tips, flower caps that turn straw yellow and do not fall off, short canes and short internodes, plus reduced yields due to a failure of flowers to set and a lack of seed development.

NOTE: See use of copper for post harvest sprays in the diseases section of this guide. Copper toxicity to vines may result from repeated applications of copper to soils or vines. 

Sulphur

Sulphur is applied to grapes for the control of powdery mildew. Replacement of sulphur with other fungicides may result in the need for sulphur applications in some areas. 

Sulphur is part of protein and of some volatile components. It is involved with the formation of chlorophyll. Deficient vines may have deficiency symptoms which are very similar to a nitrogen deficiency in the early stages. This progresses in more severe cases to restricted shoots. Shoots may be thin, stiff and upright. Terminal leaves are light green. There is a yellowing and sometimes orange and red tinting of terminal leaves together with some black (necrotic) spots or spotting between the veins.

Table 4.14 Sources of sulphur

Formulation % sulphur
Ammonium thiosulphate 26
Ammonium sulphate 24
Potassium sulphate 18
Sulphate of potash-magnesia 18 to 22
Epsom salts Mg SO4 10
Elemental sulphur 90-99
Gypsum 16 to 18

Sulphur is a minor element which is sometimes not present in the soil in adequate amounts. High pH soils (over 8.5) may require acidification (see write-up on soil acidification). Sulphate-sulphur is the only form that is directly available to vines. It is therefore the form of sulphur that should be used to correct nutrient deficiencies. Some fertilizers contain sulphate-sulphur as a secondary ingredient; e.g. ammonium sulfate (21-0-0), Epsom Salts (magnesium sulphate), potassium sulphate (0-0- 50), gypsum (calcium sulphate). Generally, the use of acidifying fertilizers such as 21-0-0 on soils with a high pH, and the use of non-acidifying fertilizers such as gypsum or epsom salts on acid soils, will ensure sufficient sulphur for adequate nutrition.

Soil Reaction and Influence of pH Availability of Nutrients

Figure 4.8 illustrates the relationship between pH and the availability of various plant nutrients. Each element is represented by a band as labelled. The width of the band at any particular pH value indicates the relative availability of the element at different pH values; the wider the band, the more favourable the uptake. The total amount present is not indicated, however, since this is influenced by additional factors, such as cropping, fertilization, and the chemical composition of soil minerals. Molybdenum, an essential element, has not been thoroughly investigated. Indications are, however, that liming and high pH promote its availability. 

Lime Applications to the Soil

Poor vine growth may result where soils have become too acidic (pH below 6.0). Lime applications are required to correct these low pH values. Most virgin soils in the British Columbia Interior are neutral or alkaline (i.e. pH 7.0 or higher). However, the use of nitrogen fertilizers and continued irrigation for many years favours the development of acidic conditions which are caused by leaching calcium, magnesium and other elements. Such effects are most pronounced in coarse textured soils and are often restricted to areas where fertilizers have been applied. Frequent determination of soil pH is recommended so that corrective liming can be implemented. Failure to take quick action may result in low pH values deep in the soil profile that are difficult to correct.

Figure 4.8 How Soil pH Affects Availability of Nutrients

The need for liming must be determined by a lime requirement test. 

Allow about one month between applications of fertilizer and applications of lime. Lime should not be applied to the soil immediately following or preceding a fertilizer application because the lime will cause ammonia to be released into the atmosphere and the effect of the fertilizer will be reduced.

These rates are for agricultural lime materials with a neutralizing value or calcium carbonate equivalent to 100. Rates for other materials must be adjusted according to the calcium carbonate equivalent. 

For example, calcium hydroxide (hydrated lime), as used fresh, has a calcium carbonate equivalent of 135%. Therefore, if fresh hydrated lime is used, multiply the amounts in the soil test report by 0.74.

It may be advantageous to supply part of the total lime requirement as dolomite, which contains both calcium and magnesium. However, do not use high magnesium (dolomite) lime for routine soil pH correction unless large amounts of magnesium are needed. 

In cases where dolomite is used it should comprise half, or less, of the total lime requirement. For example, if the lime recommendation is 2 t/ha, apply dolomite at 1 t/ha, or less with the balance comprised of agricultural lime, well pulverized C.A. storage lime or hydrated lime.

The lime must be broadcast evenly between the rows and must be incorporated to be effective. The effectiveness of any liming material depends upon the particle size. The finer it is ground, the greater the reacting surface and the more rapid the effect upon the pH level. Extremely coarse materials are so slow that they are not recommended.

Pulverized lime that can pass through a #60 sieve is considered fine ground (a #60 sieve has wires spaced 0.25 mm apart). 

Soil Acidification

Sometimes it is desirable to lower soil pH in order to increase the availability of some plant nutrients. Acidification may be required on soils that have a pH above 8.0. Lowering soil pH involves the same cultural practices and considerations as liming, except that different products are required. The principal agents used to lower soil pH are elemental sulphur, sulphuric acid, aluminum sulphate, and iron sulphate (ferrous sulphate). Ammonium sulphate, ammonium phosphate, and other ammonium containing fertilizers are also quite effective in reducing soil pH, though they are primarily sources of plant nutrients.

For large areas, elemental sulphur (or a mixture of it and bentonite to improve its stability and safety when handled in confined spaces) is probably the most economic product. However, elemental sulphur has to be oxidized by soil micro-organisms (Thiobacillus species) to sulphuric acid to effect a reduction in soil pH. The rate at which soil pH will decrease is related to the activity of the soil micro organisms. Sulphuric acid can of course also be used but it is unpleasant to handle as well as very corrosive. Generally, elemental sulphur when fully converted to sulphuric acid will react with three fold its applied weight of residual carbonate. As with limestone applications, limiting the maximum rate of applied sulphur at any one time (about 2 tonnes per hectare) will lower the pH gradually while preventing or minimizing the chance of salt build-up. The soil test laboratory will determine the total soil acid and sulphur requirement to attain desired soil pH upon request. 

Fertigation

Fertigation is the application of fertilizers through an irrigation system by the use of “T” tape, drippers, microjets, sprinklers, etc.

Advantages

  • Fertigation ensures the fertilizer will be carried directly to the root zone; amounts and timing of fertilizer application can be precise.
  • Avoids problems of inadequate rainfall to move fertilizer in when using trickle type irrigation.
  • Studies have shown that less fertilizer needs to be used due to direct application to root zones and therefore less to be leached as potential pollution.
  • Savings in labour

Disadvantages

  • Increased capital costs
  • Uniformity of application depends on uniform water distribution. Poor system design, plugged lines and emitters mean poor distribution.
  • Amounts cannot be varied to suit individual vine requirements.
  • Not all types of fertilizers can be used.
  • Potential for salts and pH problems in soil.
  • Irrigation system can become corroded.

Table 4.15 Examples of Fertigated Nitrogen products

Type    Solubility
Urea 46-0-20 440 gm/L of solution or 4.4 lb/gal of solution
Ammonium nitrate  34-0-0 590 gm/L of solution or 5.9 lb/gal of solution
Calcium nitrate 15.5-0-0  950 gm/L of solution or 9.5 lb/gal of solution 

Phosphorus

Not all forms of phosphorus are acceptable. For example, treble super phosphate 0•45•0 changes spontaneously to dicalcium phosphate and precipitates out, clogging lines and emitters.

Acceptable forms are: 

  • 10-34-0
  • 0-55-0
  • (phosphoric acid)
  • 10-52-10
  • 20-20-20
  • 10-45-10 

Fertilizer formulations such as ammonium polyphosphate (10-34-0) or phosphoric acid (0-55-0) can be used without forming precipitates. Precipitate problems can occur even with these forms of phosphorus, particularly with water high in Ca or Mg (above 300 ppm) or when mixing fertilizer. A test should be done if water analysis shows calcium and magnesium are above 300 ppm.

A test to determine whether precipitation will occur should be done by mixing the fertilizer solution with a sample of irrigation water in the same proportions as they would be if injected into the irrigation line. If the mixture turns cloudy, the fertilizer solution concentration is not high enough to prevent fertilizer from precipitating in the irrigation lines. 

This problem can occur if injection occurs at the same time as certain other types of fertilizers, particularly calcium nitrate, or even if one is followed by another.

Micro Nutrients

Chelates or sulphates of most minor elements can be safely applied, but they may be more efficiently applied as foliar sprays.

Equipment

A backflow prevention device is required to be placed in line before any injection equipment.

Injectors: Venturi injectors require at least a 20% pressure drop between the inlet to the Venturi (prior to a pressure reducing valve) and the outlet to the Venturi. Some growers have noted difficulty in injecting the amounts of liquid per minute that charts specify. The Venturi unit must be sized for your system. If there are too few emitters to create enough flow, too much of the flow has to go through the Venturi and the pressure differential is reduced and the required suction will not take place. If it is too low there may be no suction at all. If the flow is too low for the smallest Venturi device, you will have to use a different injection system. 

Other injector methods are:

  • Sprayer pump
  • Electric metering pump
  • Hydraulically driven ratio feeder
  • Bypass feed tank
  • Feed line into pump suction side (for systems which use a pumped water supply) 

Timers: Some growers have experienced problems with power surges and/or strikes from lightening. A basic surge suppressor or power bar used for plugging in computers will eliminate surges or spikes in voltage when power lines are struck in the vicinity. If the surge is too great, it may fry the metal oxide rectifiers in the power bar and still affect your clock. The bar will then be acting as an ordinary outlet and will not suppress surges and the rectifiers will need replacing. 

Grounding: Your clock must be properly grounded. If it is connected to your house system with a proper ground it should be fine, but if the clock is out in the field it must still be grounded properly. Use an eight foot grounding rod which must be placed no further than 12 feet from your clock. It is wise to check with an irrigation company that is familiar with proper lightening and surge protection equipment. 

Fertigation Practices

Check out this website below for information regarding tree fruit fertigation practices and information http://www.al.gov.bc.ca/treefrt/ product/ fertigation2001.pdf.

This information may be useful when considering grape fertigation.

The information presented in this website applies directly to orchard nursery stock and 1 year old trees in the orchard. It is included here as an example of considerations and the approach taken to fertigate young trees. The same type of consideration could be given to young vines, taking care not to stimulate them too much, ensuring that they mature and harden before the end of September.

Injection

Fill the lines for at least five minutes before starting injection. When injection is completed, continue running the irrigation for l/2 hour to ensure all the fertilizer solution is cleared, to ensure even distribution and to avoid clogging lines and emitters. 

The amount of time required to evenly distribute the fertilizer and to clear all lines is approximately l/2 hour of zone run time after injection has been completed.

Injection time

Note Back Flow Prevention

Farmers that have cross connection control devices installed must have them tested every year in order for the devices to be considered acting and in working order. Contact your water purveyor for information regarding the installation and testing of these devices.

Petiole and Soil Analysis

Petiole Analysis for Bearing Vineyards

Both petiole and soil analyses are the most reliable guides to fertilizer requirements for bearing vineyards. To be of greatest value, petiole analysis should be made on an annual basis. Paired comparison, one from normal and one from the abnormal condition, are frequently helpful. Using petiole analysis only when nutritional problems are suspected will not yield the greatest benefit from the analysis service. Deficiencies of various nutrients produce characteristic visual symptoms in grapes. Diagnosis of visual nutritional deficiencies can be difficult, especially if more than one element is deficient. Petiole analysis allows for a more accurate diagnosis of such problems The following general guidelines are approximate tissue values based upon available information to date, and are subject to change as more information becomes available. These values are based on grape leaf petioles taken opposite basal flower clusters at full bloom. See Table 4.14.

Procedure for Sampling Vineyards for Grape Petioles

Important

A petiole sample is only as good as the method of taking the sample. The results that are provided are only as good as the sample.

When to Sample – Bloom time.

Fee Schedule per Sample

Consult soil and tissue laboratory for up-to-date fee schedules.

How to Sample

  1. Sample only vines of the same variety and same age.
  2. Sample only the leaf petiole that is opposite the first or second flower cluster towards the base of the shoot.
  3. Take only one petiole from each plant. Collect sufficient petiole sample to produce 30 grams of dry matter (100 to 300 petioles), depending on petiole size. Varieties with large petioles, require about 100 petioles per sample. Varieties with smaller petioles require 300 petioles per sample.
  4. Dot not sample plants that have been sprayed with fertilizer.
  5. Separate the leaf blade from the leaf petiole and save the petiole only.
  6. Use an X pattern wherever possible for each variety. Avoid outside rows and vines covered with soil dust.
  7. Remember to place sample information cards inside each sample bag. Complete the application forms and attach these, plus payment, to the bags.

TABLE 4.16 Adequate nutrient range for grapes based on bloom time petiole analysis

Nutrient Method of expression V Vinifera
Nitrogen % Low vigour 0.5 to 1.2
  % Med vigour 0.55 to 1.3
  % High vigour 0.60 to 1.5
Magnesium % 0.3 to 1.5
Phosphorus % 0.15 to 0.5
Potassium % 2.5 to 4.5
Calcium % 1.0 to 3.0
Boron ppm 30.0 to 100.0
Zinc ppm 25.0 to 100.0
Iron ppm 40.0 to 300.0
Manganese ppm 30.0 to 150.0
Sulphur % 0.1 to 0.5

 

 

Variety Vigour

Low Vigour Medium Vigour High Vigour
Auxerrois Cabernet Franc Bacchus
Gamay Noir Chasselas Barbera
Kerner Ehrenfelser Cabernet Sauvignon
Ortega   Chenin Blanc
Schonburger Muscat Ottonel Chardonnay
  Optima Gewürztraminer
  Peral of Csaba Madeline Angevine
  Pinot Gris Madeline Sylvaner
  Pinot Meunier Merlot
  Pinot Noir Muller Thurgeau
  Semillon Pinot Blanc
  Siegerrebe Riesling
  Vidal Sangiovese
    Sauvignon Blanc
    Syrah

Soil Analysis

Soil analysis before planting a vineyard is important to determine the soil fertility and to incorporate any soil amendments that may be required. Soil sampling must be done carefully and accurately to be representative of the various soils in the proposed vineyard site. Soils tests after vineyard establishment provide reliable information relating to organic matter content, pH, degree of salinity and relative quantities of available plant food. Soil tests for physical or other chemical characteristics can be requested from most labs as well. All of this information is useful in establishing a fertility management program. Soil tests will not tell you the value of your land, the variety of grape to grow, or how often you should irrigate. 

Soil Testing Philosophies

Differences in interpretations of soil analysis by various soil test laboratories are based on differences in philosophy. There are three different concepts used by different organizations doing soil testing. These are: 

  1. Nutrient Ratio Concept: An ideal soil will have the following distribution of exchangeable base nutrients as a percentage of base saturation: 65 to 75% calcium, 10 to 15% magnesium, 4% potassium; or calcium/magnesium ratio of 4:1. 
  2. Fertility Management Concept: Irrespective of soil test values, the amounts of nutrients that should be added to a soil should be equal to the amount removed by the crop. 
  3. Nutrient Sufficiency Concept: A sufficient amount of a nutrient should be present in the soil to obtain optimum yield. Applying more of that nutrient will not further increase yields.

Fertilizer studies done in various parts of North America have shown that the first philosophy is irrelevant. The second philosophy does not apply to soils that have more than enough of the nutrients needed for optimum yield. The greatest promise, therefore, for having economic use of fertilizer lies with the third philosophy. It is the most conservative of the 3 approaches and recognizes the contribution made to plant nutrition by not only the surface soils, but also by the deeper soils.

The British Columbia Ministry of Agriculture and Lands uses the third philosophy in its recommendations 

Soil Sampling Methods for Vineyards

Important

A soil sample for soil tests is only as good as the methods of taking the sample. The results that are provided are also only as good as the sample.

Fall is the best time to sample soils

Submit samples for analysis at least 6 to 8 weeks before the results are needed. If samples are taken in the spring, do so before fertilizer is applied in time for results to be available.

Avoid Contamination of the Sample

How to Sample

  1. Make a map of the vineyard.
  2. On the plan – separate varieties – indicate areas that are different from each other (e.g. slope, surface soil colour, drainage, soil texture).
  3. Sample fields separately if the fertilizer use is historically different in different areas.
  4. Keeping in mind points 2 and 3, take enough samples from each area to give a good cross section of that area.
  5. Where special problems exist, sample from good and bad areas, keeping these samples separate.
  6. Sample in the area where the fertilizer has been applied.
  7. Use a clean soil auger or clean shovel. Clear away surface grass or litter, and dig a hole 40 cm deep. 
  8. Take a slice 2 to 3 cm thick and 6 cm wide, down one side of the hole, to a depth of 20cm. Trim the sides of the slice and place the slice in a pail. All soils in the same sample area are treated this way. Mix the soil in this pail thoroughly, breaking any lumps and remove large stones. Then fill the sample box. Each sample should represent a composite of soil from 5-6 locations within each sample area.
  9. Sample the rest of the hole (e.g. 20 to 40 cm) and place these samples in a second pail. Follow a similar procedure.
  10. Mark the location of the hole and each sample on the map. Mark the soil sample boxes in the same way. Fill the soil sample box. Use a separate box for each sample.

Soil Testing Laboratories

Norwest Soil Research Inc 104-19575 55A Ave Surrey, BC V3A 8P8 Tel: 604-514-3322 Fax: 604-514-3323

Pacific Soil Analysis Inc. 11720 Voyageur Way, Richmond BC V6X 3G9 Tel: 604-273-8226 Fax: 604-373-8082

Soilcon Laboratories Ltd. 275-11780 River Rd, Richmond BC V6X 1X7 Tel: 604-278-5535 Fax 604-278-0517

M & B Research and Development Ltd 10115C McDonald Park Sidney, BC Tel: 250-656-1334 Fax 250-656-0443

A&L Canada Laboratories Inc 2136 Jetstream Road London ON N5V 3P5 Tel: 519-457-2575 Fax: 519-457-2664

Compatibility Chart

It is very difficult to generalize because solubility depends on a number of factors, the most important is pH, the concentrations of the solutions and solution temperature. Any concentration of more than three products will have reduced solubility over two materials alone. This chart is only a guide, and when you may have questions do a trial mix in a bucket using representative amounts of material and water.

Certain chemicals that are used for formulating custom liquid fertilizers are incompatible in concentrated fertilizer stock solutions. This compatibility chart illustrates some of the combinations that should be avoided in the same stock solution. (Modified from Soil and Plant Labs Inc. Bellevue, WA).