Ferrous Sulphate (chemical formula FeSO₄) is an important inorganic compound. It commonly exists as blue-green crystals or granules, among which ferrous sulphate heptahydrate FeSO₄·7H₂O is the most prevalent form, and it is highly soluble in water. As an indispensable medium and trace element fertiliser for modern agriculture as well as a versatile industrial raw material, ferrous sulphate plays a vital role in plant nutrition correction, soil improvement, water treatment and chemical production.

Agricultural Applications and Correction of Plant Iron Deficiency

In agriculture and horticulture, ferrous sulphate is the most cost-effective iron source supplement for controlling crop iron chlorosis. Iron is an essential catalyst for chlorophyll synthesis, redox reactions and respiration within plants. When soil pH is high and available iron becomes immobilised, acid-loving crops such as citrus, flowers, blueberries and ornamental plants are prone to interveinal leaf yellowing and stunted growth.

Application or foliar spraying of ferrous sulphate can rapidly supply bioavailable iron to crops, accelerate chlorophyll regeneration and restore deep green foliage. Besides, it can adjust soil pH and is often applied together with organic fertiliser to create a favourable rhizosphere microenvironment for acid-preferring plants. It is also widely used in turf management to control moss and weeds.

Industrial and Environmental Water Treatment Applications

Apart from its excellent agricultural performance, ferrous sulphate has extensive applications in industrial and environmental protection sectors. In the water treatment industry, it serves as an efficient flocculant and reducing agent, commonly used for municipal sewage, printing and dyeing wastewater as well as electroplating wastewater treatment. It can effectively remove suspended solids, phosphates and heavy metals from water bodies, for instance reducing highly toxic hexavalent chromium to low-toxicity trivalent chromium, which is critical for water purification and ecological protection.

Furthermore, ferrous sulphate is a premium basic chemical raw material for manufacturing iron pigments (e.g. iron oxide red), iron oxide catalysts, leather tanning agents and wood preservatives. With its unique chemical properties, remarkable agronomic effects and broad industrial adaptability, ferrous sulphate remains an important compound for balancing soil nutrition and supporting the development of green industries.