OMRI Listed Potassium Sulfate for Organic Production
Potassium sulfate (SOP), also known as sulfate of potash, supplies essential potassium and sulfur without using potassium chloride. It is widely used in organic crop nutrition, dry fertilizer blending, and agricultural applications where chloride input must be strictly controlled.
Product Profile
|
Parameter |
Product Details |
|
Product Name |
Potassium Sulfate |
|
Common Name |
Sulfate of Potash (SOP) |
|
Chemical Formula |
K2SO4 |
|
Typical Analysis |
0-0-50 (up to 0-0-52 for soluble grade) |
|
Primary Nutrients |
Potassium (K2O) and Sulfur (S) |
|
Organic Compliance |
OMRI Listed for organic production |
|
Physical Grades |
Granular / Crystalline / Water-Soluble Powder |
|
Primary Applications |
Organic crop nutrition, fertilizer blending, chloride-sensitive crops, fertigation |
|
Packaging Options |
25 kg / 500 kg / 1,000 kg bags, or customized formats |
Technical Specifications
|
Parameter |
Technical Specification (Typical Range) |
|
Chemical Name |
Potassium Sulfate |
|
Common Name |
Sulfate of Potash (SOP) |
|
Chemical Formula |
K2SO4 |
|
K2O Content |
>= 50.0% (Soluble grade up to 52.0%) |
|
Sulfur (S) Content |
>= 17.5% - 18.0% |
|
Chloride (Cl-) |
<= 1.0% - 1.5% (Low-chloride grade <= 0.5%) |
|
Moisture |
<= 0.5% - 1.0% |
|
Water Insoluble Matter |
<= 0.1% - 0.5% (Soluble grade <= 0.1%) |
|
Particle Size |
Granular: 2.0-4.0 mm / Powder: 60-100 mesh / Soluble: Fine crystalline |
|
Appearance |
White to off-white crystalline or granular material |
|
Solubility |
Approx. 110 g/L at 20°C (Grade dependent) |
|
Packaging |
25 kg / 500 kg / 1,000 kg or customized |
|
Batch Documentation |
Batch-specific Certificate of Analysis (COA) included |
OMRI Listed Status and Organic Compliance
Exact Product Match
Confirm that the manufacturer name and product name match the OMRI certificate exactly.
Current Status
Verify expiration dates and approved product categories on the official OMRI list.
Correct Terminology
Note that OMRI Listed products are approved as inputs for organic production.
Production Source and Traceability
Raw Material Origin
Natural mined deposits vs. chemical synthesis routes.
Processing History
Chemical treatments used during extraction and refining.
Traceability
Full batch documentation linking raw material lots to shipped containers.
Grade Selection by Application
For Direct Field Application: Select Granular Grade (2.0-4.0 mm). Focus on granule hardness, dust suppression, bulk density, and uniform spreading range.
For NPK Dry Blending: Select Granular Grade. Ensure particle size matches other blend components to prevent physical segregation in storage and transport.
For Fertigation & Foliar Spray: Select Water-Soluble Powder/Crystalline Grade. Prioritize fast dissolution speed, high clarity, and minimal water-insoluble matter (<= 0.1%). Standard granular SOP is not suitable for fertigation.
Quality Control and Supply Chain Verification
Quality Control Checklist
Prior to bulk shipment, each production batch should pass testing for:
- K2O and Sulfur content
- Chloride and moisture thresholds
- Particle size sieve distribution
- Net weight accuracy and batch label traceability
Standard Sourcing Workflow
To minimize risk when establishing a new supply pipeline, we recommend following this step-by-step verification process:
Product Specification Sheet -> Lab Sample Evaluation -> Recent COA & OMRI Review -> Technical Approval -> Commercial Quotation -> Bulk Order Placement
Manufacturing Facilities and Audit Evidence
Production Line Access: Video/photos of screening, crushing, and anti-caking treatment setups.
In-House Quality Control Lab: Testing equipment used for chloride titration, purity, and moisture analysis.
Product Samples: High-resolution photos showing granule uniformity, color, and flowability.
Warehousing & Loading: Photos of palletized bags with moisture-proof liners, clearly displayed lot numbers, and container loading procedures.
Packaging and Shipping Specifications
Packaging Formats: 25 kg PE/PP woven bags, 500 kg jumbo bags, 1,000 kg jumbo bags (available with pallets, shrink-wrap, or desiccant liners).
Export Logistics: Container loading optimization (FCL loadability), moisture-proof ocean packaging, customized shipping marks, and complete export documentation (SDS, COA, Bill of Lading).
FAQ
Q: Is potassium sulfate automatically approved for organic agriculture?
A: No. Only potassium sulfate products derived from approved natural sources or processed according to strict organic standards qualify. Buyers must verify the specific manufacturer's active OMRI Listing Certificate before purchasing for organic use.
Q: What is the primary operational difference between SOP and MOP?
A: SOP (K2SO4) supplies both potassium and sulfur with virtually no chloride and a low salt index. MOP (KCl) provides higher K2O concentration (60%) but introduces significant chloride, which can damage chloride-sensitive crops like fruits, nuts, berries, and greenhouse vegetables.
Q: Can granular SOP be dissolved for fertigation or liquid blends?
A: Granular SOP is engineered for dry soil application and fertilizer blending; it dissolves slowly and contains insoluble binders or anti-caking agents. Fertigation requires a dedicated Water-Soluble Crystalline or Fine Powder Grade with water-insoluble content below 0.1%.
Q: Can we request pre-shipment sampling and third-party inspection?
A: Yes. We encourage buyers to evaluate representative lab samples before issuing purchase orders. Independent third-party inspection (such as SGS, Bureau Veritas, or Intertek) at the loading port can also be arranged upon request.
Q: Are custom particle sizes and packaging configurations available?
A: Yes. Particle size ranges (e.g., specific sizing for granular blends) and customized bag designs (25 kg, 500 kg, or 1,000 kg with custom shipping marks and moisture-resistant liners) can be produced based on agreed order volumes and lead times.
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