Crop nutrition · Soil chemistry

Your soil already has the iron.
It just can't reach the root.

Most micronutrient deficiency in Indian soils isn't absence — it's lockout. Above pH 7.5, iron oxidises and drops out of solution before a root hair ever sees it. Move the slider to your soil's pH and watch which nutrients close.

Interactive

Nutrient availability by soil pH

Bar length is the share of each nutrient a plant can actually take up at that pH. Based on the Truog availability relationship. Directional, not a substitute for a soil test.

6.5 Slightly acidic
4.0 acidic6.59.0 alkaline

At this pH

Why chelates

The same iron, twice

Both lanes start with iron at pH 8. One is a free ion. One is held inside an EDTA cage.

Fe2+ — free ion

Oxidises, precipitates as Fe(OH)3, settles out of reach.

root Fe

Fe-EDTA — chelated

The cage keeps it soluble all the way to the root.

root Fe

Reading the plant

Where the symptom appears tells you which nutrient

Mobile nutrients get pulled out of old leaves to feed new growth. Immobile ones can't move, so the youngest leaves starve first. Check the bottom of the plant before the top.

Plant showing where deficiency symptoms appear

Severity

Interveinal chlorosis, stage by stage

Veins stay green while the tissue between them yellows. Drag to see how far yours has gone. These are interpolated stages, not photographs — confirm with a leaf tissue analysis.

Healthy

No visible chlorosis. Veins and lamina the same green.