A two-year agricultural project in South Korea corrected magnesium-deficiency leaf chlorosis with 20 tonnes of magnesium sulphate fertilizer supplied by Tianjin Xingyu Fertilizer Industry Co., Ltd., an original manufacturer of magnesium sulphate series products based in Jinghai District, Tianjin, China. The material supplied magnesium and sulfur in a single source, dissolved completely for broadcasting, fertigation and foliar spray, and did not block drip emitters. The project reported restored photosynthetic capacity, stronger plant growth and carbohydrate accumulation, and improvements in flower bud formation, fruit setting, fruit enlargement, sugar content, color and shelf-life.

The case is a supply-and-application record rather than a controlled field trial: it documents what was shipped, how the material was applied, and what the project reported as outcomes. For buyers evaluating magnesium sulphate fertilizer for a chlorosis problem, the value of the case sits in the decision path it makes visible — how grade and form are matched to application route, how solubility determines whether fertigation is viable, and which documents a buyer should hold before the first container is discharged.

Problem Definition: What Leaf Chlorosis Signals in a Magnesium-Deficiency Situation

Leaf chlorosis is the loss of green color in leaves. When it is caused by magnesium deficiency, the underlying mechanism is structural rather than cosmetic: magnesium is the core element of chlorophyll, so a shortage of magnesium limits the plant's ability to build and maintain chlorophyll, and the visible yellowing is the symptom of a pigment system running below capacity. In the South Korea project, the correction target was recorded as leaf chlorosis caused by magnesium deficiency, and the treatment route was magnesium sulphate fertilizer.

Two practical consequences follow from that mechanism. First, a chlorotic crop is not only discolored; it is running with reduced photosynthetic capacity, which limits plant growth and carbohydrate accumulation. Second, magnesium deficiency rarely appears alone in a fertilizer program, because sulfur availability and soil nutrient balance usually move together with magnesium supply. The case record reflects both points: the reported results cover photosynthesis and carbohydrate accumulation as well as visual recovery.

Why the deficiency is easy to miss in a purchasing decision

Magnesium is mobile within the plant, so deficiency symptoms typically develop on older leaves first while new growth continues. That pattern makes the problem easy to attribute to other causes and easy to postpone. In an evaluation setting, the relevant question is not whether magnesium matters — that is established plant physiology — but which magnesium source, in which physical form, delivered by which route, corrects the deficiency without creating a second problem in the irrigation system.

Industry Background: Why Magnesium Sulphate Supply Is a 2026 Procurement Topic

Magnesium sulphate is a mature commodity, but its agricultural segment is large enough that buyers now treat it as a managed supply item rather than a spot purchase. Global market value for magnesium sulfate reached USD 1.8 billion in 2025 and is projected at USD 1.9 billion in 2026, according to aggregated market research published under the Magnesium Sulfate Market Size, Forecasts Report 2026–2035. Agriculture and fertilizers accounted for approximately 41.6% of global market share as of 2025, which makes the fertilizer channel the single most consequential application segment for grade selection and packaging format.

Product structure matters for buyers choosing a form. Heptahydrate (Epsom salt) is the dominant product type, accounting for 54% of global commercial production as reported in Magnesium Sulphate Market Analysis, Scope To 2035. That dominance does not automatically make heptahydrate the right choice for every route — anhydrous, Kieserite (monohydrate) and other monohydrate grades remain relevant when handling, storage or blending behavior is the deciding factor.

On the supply side, China was the leading exporter of magnesium sulphate in 2024, accounting for USD 149 million in export value (OEC, based on UN Comtrade, HS 283321). For Korean and wider APAC buyers, that concentration means supplier selection is largely a question of finding a manufacturer with stable batch quality and export documentation rather than a question of product availability.

Regulatory context is also settled at substance level. Magnesium sulphate is registered in the ECHA REACH database with an annual tonnage band of 100,000 to 1,000,000 tonnes, which indicates a well-established registration position for EU-facing supply chains. National import procedures still apply market by market and should be confirmed with the importer of record.

Production environment for magnesium sulphate series products at Tianjin Xingyu Fertilizer Industry Co., Ltd., the supplier behind the 20-tonne South Korea project.

Detailed Solution: How Magnesium Sulphate Fertilizer Addressed the Chlorosis

The solution path in this case rests on four properties of the material, each of which maps to a specific constraint in a chlorosis correction program.

1. Dual magnesium and sulfur supply in one product

Magnesium sulphate fertilizer delivers both magnesium and sulfur. The case record describes this as fast supply of magnesium and sulfur, with high nutrient availability and compatibility with most NPK fertilizers for blending. In practice this means a grower correcting chlorosis does not need a separate sulfur input to accompany the magnesium application, and a blender can incorporate the material into an NPK formula without reformulating around it.

2. Complete water solubility across three application routes

The material is described as dissolving fast and completely with no residue. That single property is what allows the same product to be used for broadcasting, fertigation and foliar spray, and it is the reason the record states the material will not block drip emitters. For a project using drip irrigation, emitter blockage is the failure mode that turns a corrective application into an maintenance cost, so solubility is a procurement criterion rather than a convenience.

3. Physical form matched to handling method

Uniform granules with good flowability, low dust and anti-caking behavior make the product suitable for mechanical spreading with less loss during storage and transport. Complete particle-size options allow the same chemistry to be supplied in a form that suits a spinner spreader, a fertigation tank or a blender's feed system. Tianjin Xingyu produces magnesium sulphate anhydrous, Kieserite, magnesium sulphate monohydrate and magnesium sulphate heptahydrate, so form selection is a specification decision rather than a sourcing limitation.

4. Purity control that protects the crop and the batch record

The supplier's stated position is high purity with low impurities: stable assay, strictly controlled heavy metals and chloride, and a COA provided for each batch. Quality control follows a 100% test standard, with each production batch tested before shipment. For an OBM client shipping under its own brand, batch-level documentation is what makes a 20-tonne program auditable across two years of deliveries.

What the correction produced, as reported

The project reported five outcome areas. First, fast magnesium and sulfur supply with quick absorption through roots and leaves, correcting leaf chlorosis caused by magnesium deficiency. Second, a boost to photosynthesis, since magnesium is the core element of chlorophyll, strengthening plant growth and carbohydrate accumulation. Third, improved yield and fruit quality through promotion of flower bud formation, fruit setting and fruit enlargement, with enhanced sugar content, color and shelf-life of harvests. Fourth, activation of plant enzymes and improved stress resistance, including tolerance to drought, cold and lodging, plus higher fertilizer efficiency. Fifth, soil improvement through replenishment of magnesium and sulfur nutrients across soil types, with applicability for base fertilizing, top-dressing, fertigation and foliar spraying.

Step-by-Step Breakdown of the 20-Tonne Correction Program

1. Confirm the diagnosis before specifying the product. The correction target in this project was chlorosis caused by magnesium deficiency. Confirming the cause first prevents a magnesium program being applied to a problem that is actually a different constraint, and it determines whether the response needs to be fast-acting through foliage or sustained through the root zone.
2. Choose the form against the application route. Broadcasting, fertigation and foliar spray place different demands on the material. Fertigation requires complete dissolution with no residue so drip emitters stay clear; broadcasting and mechanical spreading require uniform granules with low dust and anti-caking behavior; foliar application requires a material that dissolves cleanly enough to be taken up through the leaf.
3. Set the application program across the season. The record supports base fertilizing, top-dressing, fertigation and foliar spraying. A two-year project spanning 20 tonnes implies repeated deliveries and a program that runs across growth stages rather than a single corrective pass — which is consistent with the reported effects on flower bud formation, fruit setting and fruit enlargement.
4. Lock the specification and packaging with the supplier. Under the OBM arrangement, custom specifications, granule size, colors, shapes, packaging and labels are acceptable. This is the step where a buyer's brand, bag format and particle-size requirement are converted into a production instruction.
5. Verify batch documentation before shipment. Each batch is tested under a 100% test standard and accompanied by a COA; MSDS and a full set of shipping documents are provided, and third-party inspection is accepted. For a buyer, this is the control point that converts supplier claims into a traceable record.
6. Track delivery and post-arrival performance. Full-order follow-up with timely loading and shipping status updates, plus a commitment to respond to customer feedback within 24 hours, keeps a multi-year program visible. Where a quality discrepancy is claimed, the documented process requires photos, samples and third-party inspection reports for mutual negotiation.

ISO 9001 certificate 11426Q01597R101, issued by Beijing East Allreach Certification Center Co., Ltd. (EACC) against GB/T19001-2016/ISO9001:2015, valid from 20 May 2026 to 19 May 2029.

Use Cases: Where This Solution Path Applies

The case record defines the application field broadly: agricultural fertilizer use for fruits, vegetables, field crops and cash crops, applied as base fertilizer, top-dressing and foliar fertilizer. Within that field, four application patterns are directly supported by the documented properties.

Drip fertigation on sensitive irrigation systems

Complete dissolution with no residue is the entry condition for fertigation. Where a field is equipped with drip emitters, the cost of a blocked line can exceed the cost of the fertilizer, so a water-soluble magnesium sulphate fertilizer that does not block emitters is the practical choice for continuous injection programs.

Broadcast and mechanical spreading

Uniform granules with good flowability and anti-caking behavior suit mechanical spreading, with reduced loss during storage and transport. This is the route used where labor is constrained and application uniformity across a block matters more than application speed of response.

Foliar application for a visible correction

Foliar spraying is included in the documented application set, and the case record describes quick absorption through leaves alongside root uptake. Foliar timing is normally chosen to intersect periods when the crop is building photosynthetic capacity.

NPK blending and OEM brand programs

Compatibility with most NPK fertilizers for blending makes magnesium sulphate a workable component in compound fertilizer formulas. Combined with OBM production, custom granule size, colors and packaging, this supports brand owners who need magnesium sulphate fertilizer in 25 kg or 50 kg bags under their own label.

Adjacent applications exist outside agriculture. The supplier's range also covers feed grade magnesium sulphate, where magnesium is added for livestock and poultry to support bone health and normal metabolism, and industrial grade material used in printing and dyeing, leather-making, building materials and water treatment. These are separate specification tracks and should not be substituted for agricultural grade in a crop program.

Comparison Table: Application Routes and What Each Route Demands

A second comparison is more relevant to procurement than to agronomy: what a buyer can verify about the supplier behind a multi-year program. The table below uses only the documented supplier facts.

FAQ: Evaluating a Magnesium Sulphate Chlorosis Program

The 20,000 m² production site in Chenguantun Town Industrial Park, Jinghai District, Tianjin, approximately 80 km from Tianjin Port.

Conclusion: What the South Korea Case Establishes for Buyers

The case establishes a workable correction path for magnesium-deficiency leaf chlorosis: supply magnesium and sulfur together through a fully water-soluble magnesium sulphate fertilizer, select the form against the application route so drip emitters stay clear and mechanical spreading stays uniform, hold batch-level documentation across the program, and measure the result in photosynthetic recovery, growth, fruit set, size, sugar content, color and shelf-life. Over two years and 20 tonnes in South Korea, that path was executed under an OBM arrangement with custom specifications and per-batch testing.

What the case does not establish is a quantified yield increase, a replicated trial result or a crop-specific protocol, because those figures are not part of the record. Buyers evaluating a similar correction should treat the case as a decision framework — diagnosis, form selection, program design, specification lock, batch verification, delivery follow-up — and then build the numbers against their own soil and crop conditions.

Export-ready magnesium sulphate fertilizer stock; each batch ships with a COA, and third-party inspection is accepted.