Available silicon
Rice and sugarcane ask more often. Not a cure-all.
Also called: available Si, available silica
Speed
- Available silicon — rice asks more often.
- Total Si is a different cell.
- Acid soils often test lower.
- Silicon is not a pesticide.
How it appears on the sheet
The sheet says available silicon, often mg/kg. Methods differ — don’t mix labs.
A sketch. Do not fertilise from the picture alone.Common units
Available Si often mg/kg. Rice and sugarcane look here more often.
Soil:water ratio · Total Si and available Si are different cells. Acid soils often test lower.
How to read the number
Silicon helps grasses. It does not replace drainage or nitrogen.
Rates from the label and the station. This page does not hand a bag count.
Thresholds only, not a prescription. Rates live in the field guide. This page does not hand you a bag count.
| Cell | Low | Mid | High |
|---|---|---|---|
| Available Si mg/kg (sketch) | Rice stems go soft | Enough for many paddies | More is not a yield switch |
Regional classes differ. This table is a comparison, not a prescription.
What it looks like in the field
Rice that lodges and stays diseased is when people ask Si. Still read N, water and roots first.
Don’t do this
- Don’t treat Si as a pesticide.
- Don’t mix lab methods.
- Don’t skip N, water and roots.