CMS (Calcium-Magnesium-Sulphur) fertilizer

CMS granular fertilisers are FCO-notified secondary-nutrient products combining calcium, magnesium and sulphur in a single granule. In chilli they are positioned as a side-dressing input at pod-filling to support cell-wall calcium, chlorophyll-magnesium and amino-acid sulphur metabolism. The related general entry is Cms Calcium Magnesium Sulphur.

Composition

A representative CMS analysis carries approximately 20% calcium-equivalent, 5% magnesium and 20% sulphur, although formulations vary by manufacturer. Granules are typically a compacted blend of gypsum, dolomite or kieserite, and elemental sulphur, of 2-4 mm size, FCO-notified under the secondary-nutrient schedule. Major Indian suppliers include Coromandel and IFFCO.

Mode of action

After incorporation into moist soil the granule slowly disintegrates and releases the three nutrients over the crop cycle. Calcium goes into the developing cell walls of fruits and growing tissue; magnesium feeds the chlorophyll molecule and enzyme activity; sulphur enters the synthesis of cysteine, methionine and oil compounds.

Target use and dose

In chilli, CMS is applied at flowering/fruit-set as a side-dressing along the rows at approximately 50 kg per acre, with adequate moisture to ensure dissolution. In paddy, it is used at booting to address simultaneous Ca-Mg-S deficiency on intensively cropped soils. The product is suitable for both broadcast and row-side application but should be incorporated lightly into the surface soil for best uptake.

Safety and regulatory status

Notified under the FCO 1985 secondary-nutrient schedule. Granules are non-hazardous. As with Calcium Magnesium Foliar sources, calcium nitrate and magnesium sulphate must not be combined in fertigation stock tanks; CMS avoids this issue by delivering both nutrients as low-solubility salts directly to soil.

References

Calcium Nitrate Fertilizer. Gardening Know How.
Magnesium Sulfate Fertilizer Benefits. Green Gubre Group technical resource.