When selecting potassium humate, it is crucial to focus on the source of raw materials, the content of active ingredients, water solubility, and product form to avoid purchasing inefficient or counterfeit products. The following is a practical selection guide based on authoritative information:
1. Clarify Product Type: Potassium Humate vs. Potassium Fulvicate
Potassium Humate: Extracted from lignite or weathered coal using an alkaline process, with a humic acid content ≥55% and a potassium (K₂O) content of 8%-11%. It has good water solubility, is alkaline, and can improve soil and increase potassium fertilizer utilization, but its effectiveness is moderate.
Potassium Fulvicate: The smallest molecular weight and most active component of humic acid, with a fulvic acid content ≥50% and a potassium content ≥12%. It has excellent water solubility, allowing for rapid absorption by crop roots and leaves, resulting in faster effects and higher activity, making it the first choice for foliar spraying and drip irrigation. Key Points: Potassium humate is often advertised as "mineral-derived potassium humate," which is a high-quality product. However, "biochemical potassium humate," made from sugarcane bagasse, monosodium glutamate waste, etc., has low activity, requires large quantities, and has poor effects; although cheaper, it is not cost-effective.
2. Core Selection Criteria
Check Raw Materials: Prioritize "mineral-derived" products made from weathered coal and lignite. Weathered coal from Xinjiang and Inner Mongolia is of higher quality. Avoid products of unknown origin or those labeled as "biochemical" or "plant residue."
Check Content: Check the packaging label to ensure:
Humic acid (or fulvic acid) content: ≥50% (high-quality standard); below 40% has limited effectiveness.
Potassium oxide (K₂O) content: ≥12% (potassium humate) or 8%-11% (potassium humate). Water solubility test: Add a small amount of product to clean water. High-quality product should dissolve completely within 30 seconds, leaving a dark brown or brownish-brown liquid with no sediment or residue. Slow dissolution, flocculent matter, or sediment indicates low purity or impurities.
Appearance and odor: Genuine product is a black powder or granules with no pungent odor (such as ammonia or acid). Do not purchase if the product is abnormally black (possibly dyed) or white ("white humic acid" is a misleading term).
3. Choose the form according to the intended use:
Follicular spraying, drip irrigation, seed soaking: Choose potassium humate (liquid or high-purity powder) with good water solubility for fast results. A concentration of 0.1%-0.2% is recommended.
Base fertilizer, fertigation: Potassium humate or humic acid organic-inorganic compound fertilizer can be selected for long-term improvement of soil structure.
For acidic soil improvement: Choose nitrohumic acid (strongly acidic), but it is prohibited for alkaline soils.
In summary: Choosing "mineral-derived potassium fulvate," ensuring it contains "≥50% fulvic acid, ≥12% potassium, is fully water-soluble, and has no precipitation," is the most efficient, cost-effective, and environmentally friendly option.
