Educational Diagrams
Original WAFRA CITY illustrations explaining where fertiliser goes, how to read a label, what over-application looks like, and how to plant and measure safely.
Where fertiliser goes
- Correct — across the root zone, towards and beyond the canopy edge
- Wrong — hard against the trunk: outside the active zone, and it concentrates salt at the stem base
- Drip line — the line beneath the canopy edge
An important limit: under drip irrigation roots do not necessarily follow the canopy edge but concentrate where the water wets the soil. On a drip-irrigated tree the wetted pattern is the better guide.Original WAFRA CITY illustration. No distance or quantity is shown — those depend on species, age and irrigation system, and are settled by a site assessment and the product label.
Reading the label
- The three numbers Nitrogen, then phosphorus as P₂O₅, then potassium as K₂O — percentages by weight, not a quality score. The last two are oxides, not elements.
- The declared analysis Every nutrient and its proportion, including what the three numbers omit — sulphur, calcium, magnesium and micronutrients.
- Amount, method and timing The crops named, the amount, and whether it is applied through irrigation water or to the soil. This is the binding reference.
- Safety and storage Precautions, protective equipment and storage. Completed by the safety data sheet.
Macro and micro — the difference in scale
- N · K about 80% of the plant's mineral nutrients
- P · S · Ca · Mg 19% together
- All micronutrients under 1% combined — the thin sliver at the end
To put the gap in scale: the ratio of nitrogen to molybdenum in plants is about 10,000 : 1, and plants need roughly forty times more magnesium than iron.
The damage that looks like hunger
Fertiliser burn — days
Fertiliser is salt. Applied heavily or onto dry soil, it raises the concentration around the root until water is drawn out of it. The plant wilts in moist soil and does not respond to watering.
Salt accumulation — seasons
Under drip, salts move to the edge of the wetted zone and concentrate there. The white crust appears at the rim, not at the emitter.
Both are misread as hunger — and neither is ever treated with more fertiliser.Original WAFRA CITY illustration. Sources: FAO Soils Portal, Salt-affected soils; FAO Fertilizer Bulletin 16, Chapters 3 and 4.
Planting depth
Correct
The root flare sits at surface level. The hole is wide, not deep, its sides broken, and it is backfilled with the original soil.
Wrong
The trunk enters the soil like a post and the flare is buried. A narrow deep hole acts as an underground pot and invites settling.
The fertigation path
- 1Water sourceAnalyse it — it adds salts with every watering
- 2Highly soluble fertiliserThe only form suitable for drip
- 3InjectorAt a rate the label sets
- 4FilterThe first point of failure — check after every storm
- 5EmittersTheir position decides where roots grow
- 6Root zoneWhere the water actually wets the soil
The cost is real: drip and sprinkler are technically more complicated, and sediments may clog emitters. Step 4 is the one that fails in practice.Original WAFRA CITY illustration. Sources: FAO Fertilizer Bulletin 16 (Glossary) and FAO Irrigation Manual 5.
Containers — the two failure modes
Heavy watering → leaching
Small volume, free drainage — soluble nutrients leave through the base.
Sparse watering → salt build-up
Salts have nowhere to go and concentrate in a small volume — the white crust is the sign.
Mulch placement
Correct — an open ring
Bark visible and dry at the base. The layer is even and spread wide towards the canopy edge.
Wrong — piled at the trunk
The bark is buried and permanently damp — the commonest and most damaging error.
Note: coarse un-decomposed material can temporarily lower available nitrogen, so yellowing after a heavy dressing may be tie-up rather than a soil shortage.Original WAFRA CITY illustration. No depth is shown — we found no sourced figure for one. Source: FAO Bulletin 16, Chapter 3.
Measuring and applying safely
- Read the label firstIncluding the safety section, before opening the bag
- Measure by weightAn unmarked scoop does not tell you a weight — bulk density differs between products
- Work out the actual nutrientQuantity × percentage ÷ 100, then convert the oxides
- Apply in the root zoneNot at the trunk, and never into a palm crown
- Water it inSurface nitrogen on alkaline soil is lost as ammonia
- Reseal, store and labelDry, closed, in the original container, away from children and animals
What the three numbers mean
Nitrogen
Leafy growth and green colour
Nitrogen is part of chlorophyll — the green pigment in leaves — and an essential constituent of all proteins. FAO records it as responsible for the dark green colour of stem and leaves, vigorous growth, branching and tillering, leaf production, size enlargement and yield formation. It is the most abundant mineral nutrient in plants.
Phosphorus
Roots, energy and fruit formation
Phosphorus is essential for growth, cell division, root lengthening, seed and fruit development, and early ripening. It is part of several compounds including oils and amino acids, and its compounds ADP and ATP act as the energy carriers within the plant. It is far less abundant than nitrogen or potassium — about one-fifth to one-tenth the concentration of nitrogen.
Potassium
Water, quality and resilience
Potassium is the second most abundant mineral nutrient in plants after nitrogen. It is involved in the working of more than 60 enzymes, in photosynthesis and in moving its products to storage organs — seeds, tubers, roots and fruits — in water economy, and in providing resistance against a number of pests, diseases and stresses such as frost and drought. It regulates stomatal opening and therefore the plant's internal water relations.
Where a deficiency shows — and why there
Direction mobile nutrients travel under shortage
-
Growing points
- B Boron
- Ca Calcium
- Cu Copper
The nutrient cannot move at all — new growth is hit first and cannot be rescued from the old leaves.
-
Younger leaves
- Cl Chlorine
- Fe Iron
- Mn Manganese
- S Sulphur
- Zn Zinc
The nutrient is barely mobile in the phloem, so the plant cannot draw it out of an old leaf to feed a new one.
-
Middle and older leaves
- Mo Molybdenum
Moderate mobility — the symptom appears in the middle of the plant rather than at either end.
-
Older leaves
- Mg Magnesium
- N Nitrogen
- P Phosphorus
- K Potassium
The nutrient is mobile, so the plant moves it out of the old leaves into the new ones — the old yellow first while the top stays green.
The planting sequence
-
Wide, not deep
Width helps roots spread; extra depth makes the tree sink. Roughen the sides.
-
Check the roots
Tease out or cut circling roots now — they will not correct themselves after planting.
-
Root collar at the surface
The trunk flare visible at or slightly above the surface. A buried collar is close to irreversible.
-
Backfill, water, mulch
Backfill with the soil you removed, water the root ball, leave a gap at the trunk. No fertiliser yet.
And no fertiliser in the hole: roots at planting are damaged, are not absorbing efficiently, and fertiliser in contact with them can cause injury.Original WAFRA CITY illustration. Planting mechanics are horticultural and arboricultural common ground, labelled as such in the planting guides. Soil source: FAO Bulletin 16, Chapters 4 and 5.
The fruit-tree year — nine stages
- Before planting Drainage; soil and water analysis
- Establishment Water continuity
- Bud break and shoot growth Nitrogen supports canopy build
- Pre-flowering Excess nitrogen delays maturity
- Flowering A sensitive window — heat and wind disrupt set
- Fruit set Water consistency
- Fruit development Potassium removal is high
- Post-harvest Canopy recovery
- Dormant period Deciduous trees only
Stage 9 does not apply to every tree. Grape, fig and mulberry are deciduous and have a genuine dormancy; citrus, mango and olive are evergreen and have no equivalent. Calendar feeding of a bare tree is a listed mistake in those guides — a dormant tree is not using nutrients as a growing one does.
The seven vegetable families
Fruiting
Grows and fruits at the same time — management is a constant choice between the two jobs.
Cucurbits
Separate male and female flowers — failed set may be pollination, not nutrition.
Leafy
The one family where nitrogen is the yield — and bolting ends everything.
Brassicas
Named by FAO: N, P, K plus sulphur and boron. Boron only after analysis.
Root and bulb
Soil condition beats nutrition — and excess nitrogen actively spoils the product.
Legumes
They make their own nitrogen — and generous feeding switches that off.
Culinary herbs
A kitchen shelf, not a family — half want water and richness, half are harmed by both.
Where the crop is decided — by family
Fruiting vegetables
- Establishment
- Vegetative growth
- Flowering
- Fruit set and fillThe crop is decided here
Decisive stage: Fruit set and fill. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
Cucurbits
- Establishment
- Vegetative growth
- Flowering and pollinationThe crop is decided here
- Harvest
Decisive stage: Pollination, then fruit fill. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
Leafy vegetables
- Establishment
- Vegetative growthThe crop is decided here
- Flowering
- Harvest
Decisive stage: The vegetative phase IS the crop. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
Brassicas
- Establishment
- Vegetative growth
- Flowering
- Head or curd formationThe crop is decided here
Decisive stage: Head or curd formation. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
Root and bulb
- Establishment
- Vegetative growth
- Flowering
- Storage-organ bulkingThe crop is decided here
Decisive stage: Storage-organ bulking. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
Legumes
- Establishment
- Vegetative growth
- Flowering and pod setThe crop is decided here
- Harvest
Decisive stage: Flowering and pod fill. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
Culinary herbs
- Establishment
- Vegetative growthThe crop is decided here
- Flowering
- Harvest
Decisive stage: Repeated cutting — no single yield stage. Before it, nitrogen builds the frame; from it, nitrogen is restrained.
About these illustrations
Every illustration here is an original WAFRA CITY illustration, built from the same identity colours the site uses. No commercial graphic or external source is copied, so there is no external licence to record.
Their text is real text rather than image, so it translates, selects, is read aloud by a screen reader, and adapts to right-to-left.
No illustration here states a quantity, a rate or a product. The authority for quantity is the product label and the result of your own soil and water analysis.