Single Super Phosphate (SSP)

Imagine two versions of the same spice, one concentrated and imported at a premium, the other milder, locally made, and considerably cheaper, though a cook needs to use more of it to get the same effect. Single Super Phosphate, or SSP, is the milder, more local option in India's phosphate fertiliser story, standing in contrast to the concentrated, import-heavy DAP.

SSP is manufactured by treating rock phosphate with sulphuric acid, a comparatively simple industrial process that can largely be done with domestically available or more diversely sourced raw materials, unlike DAP's heavier reliance on imported finished fertiliser and phosphoric acid. Its phosphorus content is much lower, around 16%, compared to roughly 46% in DAP, meaning a farmer needs a larger quantity of SSP to deliver the same amount of phosphorus to a field.

What SSP loses in concentration, it partly makes up for in a bonus most farmers value directly: it also contains sulphur and calcium, secondary nutrients that DAP does not supply, and which have become increasingly recognised as limiting factors in many Indian soils after decades of DAP-heavy fertilisation.

Because it depends far less on imported inputs, SSP has been actively promoted by policymakers as a way to ease the pressure on India's phosphate import bill, particularly for crops and soil types where its nutrient profile is not a meaningful disadvantage.

Whenever a state agriculture department pushes farmers to use more SSP instead of DAP, the reasoning is rarely just agronomic, it is very often also about quietly reducing the country's phosphate import dependency one bag at a time.