Total S-stock
Definition
Total S-Stock refers to the total amount of sulphur (S) present in the soil, expressed in kilograms per hectare. Similar to nitrogen, a large proportion of this sulphur is stored in soil organic matter rather than in immediately available forms.
Importance
Sulphur is an essential nutrient for plant growth, playing a key role in protein synthesis and enzyme function. Although the total S-stock represents a significant reserve, only a small fraction becomes plant-available sulphate through mineralisation, which typically occurs between April and late August during the growing season.
Comparison with nitrogen
While sulphur follows similar principles to nitrogen in terms of storage and release, the amount of sulphur in soil organic matter is considerably lower than nitrogen. This means sulphur reserves are more limited and require careful management to avoid deficiencies.
Factors influencing S-Stock
- Organic Matter Content: Higher organic matter generally means more sulphur storage.
- Soil type: Sandy soils often have lower sulphur reserves compared to clay soils.
- Management practices: Organic amendments and crop residues can help maintain sulphur levels.
Role in soil ecosystem
Sulphur contributes to soil fertility and crop health by supporting protein formation and disease resistance. Adequate sulphur levels are essential for balanced nutrient supply and sustainable agricultural production.
