Nutrient composition and release mechanism in soil
Plants cannot absorb elemental sulphur directly; it must undergo biological oxidation into sulphate ions (SO4²⁻).
The scientific release mechanism works as follows:
- Composition: 90% elemental sulphur (S) combined with 10% sodium bentonite clay binder.
- Moisture absorption: When applied to soil, the bentonite clay absorbs moisture and expands up to 15 times its volume.
- Granule dispersion: Swelling fractures the sulphur into microscopic particles, exponentially increasing the surface area.
- Microbial conversion: Soil microorganisms, primarily Thiobacillus bacteria, biologically oxidize the elemental sulphur into plant-available sulphate.
- Sustained nutrient availability: Releases sulphate progressively throughout the crop growth cycle, reducing leaching losses in sandy and irrigated soils.
Crop benefits across oilseeds, pulses and cereals
Sulphur plays a pivotal role in the synthesis of sulphur-containing amino acids (methionine, cysteine, and cystine) and chlorophyll.
Key crop benefits include:
- Mustard and Groundnut: Directly increases seed oil concentration, pod filling, and test weight.
- Soybean and Pulses: Promotes nodulation by rhizobium bacteria, enhancing biological nitrogen fixation and seed protein yield.
- Sugarcane: Improves cane diameter, internodal length, and commercial sugar recovery percentage.
- Onion and Garlic: Stimulates the synthesis of allyl propyl disulphide compounds, boosting pungency, bulb size, and post-harvest storage life.
Soil application methods and testing
Farmers should base sulphur application rates on Soil Health Card recommendations. Broadcast Bentonite Sulphur as a basal dressing during land preparation or early vegetative sowing, incorporating it into the upper 5 to 10 cm of moist soil. Avoid surface application without soil incorporation, as adequate soil contact and moisture are essential for rapid particle dispersion.
Official source
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Department of Fertilizers, Ministry of Chemicals & Fertilizers ↗Related on KisanPe
Common questions
What is Bentonite Sulphur and how does it work?
It is a 90% elemental sulphur fertilizer with 10% bentonite clay that swells in soil moisture, dispersing sulphur for microbial conversion into plant-absorbable sulphate.
Why is sulphur critical for oilseed crops like mustard and groundnut?
Sulphur is essential for oil synthesis, enzyme activation, and amino acid production, directly enhancing seed oil percentage and yield.
When should Kisan Bentonite Sulphur be applied to fields?
It is best applied as a basal dressing during final land preparation or sowing, ensuring proper incorporation into moist soil.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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