Mekong Delta Acid Sulfate Soil Humic Acid Granules 4-6mm Calcium Magnesium Enriched Rice Paddy Grade

We build this granule for one specific field problem: rice land in the Mekong Delta where the subsoil turns bright yellow at 40cm and the pH of the standing water sits between 3.5 and 4.5 after the first flush of the dry season. In that condition aluminium becomes mobile, phosphate is locked onto iron and aluminium oxides, and no amount of urea or DAP rescues a thin crop. Our answer is a 4-6mm leonardite granule carrying 65% humic acid together with calcium and magnesium, so the farmer corrects acidity and feeds organic carbon in a single mechanical pass.

The raw material is weathered lignite from our own pit in Ningxia, oxidised naturally for millions of years and milled to 100 mesh before granulation. We do not blend in spent mushroom substrate or lignite ash the way some Vietnamese blenders do, because those fillers dissolve into a sludge that blocks the seeder. Every lot is assayed for humic acid, CaO, MgO and moisture, and the granule is cured for seven days so it survives a two-week sea freight to Cat Lai or Hai Phong without turning back into powder in the bag.

Because we sell to dealers who resell to cooperatives, we keep the honest part in writing: this is a soil amendment, not a yield miracle. On a heavily jarositic field it will not replace lime in the first season. What it does is hold the calcium you apply, keep pH from crashing back after rain, and give the root zone something to build structure on. That is why most of our Delta buyers order the 4-6mm grade rather than powder, and why they reorder before the second crop instead of after it.

• Built for jarosite layers: Granule alkalinity is deliberately held above pH 8.5 so each prill neutralises a pocket of acid around it instead of dissolving uselessly in the floodwater
• Calcium plus magnesium in the prill: 8% CaO and 3% MgO reduce the exchangeable aluminium fraction while feeding the magnesium that acid sulfate rice is usually short of
• Twelve newton crushing strength: Passes through broadcast spreaders and row seeders on wet paddy soil with less than 3% fines after handling, which keeps dust out of the ditch water
• Controlled release over 60 to 90 days: The granule swells and breaks down slowly, matching the tillering window rather than dumping everything into the first irrigation
• Traceable pit to bag: Lot number, mining batch and granulation date printed on the bag; retained sample kept 24 months for any claim
• Low chloride: Cl below 0.5% so repeated application on the same plot does not push salinity up in coastal Tra Vinh and Soc Trang fields

Designed for acid sulfate paddy on the Cai Be, Long Xuyen and coastal Soc Trang belts, where the standard local practice is lime plus urea plus a phosphate fertiliser. Apply 300-600 kg per hectare as a basal dressing at final harrowing, or 150-200 kg per hectare at 20 to 25 days after transplanting if the field was limed the previous season. Keep granules out of concentrated bands near the seed row; broadcast and incorporate to 8cm gives the best contact with the acid layer.

The same grade works for the raised beds between paddies where farmers grow vegetables in the dry season, and for newly reclaimed shrimp-to-rice converted land. In those plots a lower rate of 250 kg per hectare is enough because the organic matter load is already high.

Each 25kg bag is packed in a PP woven outer with a PE liner at 0.05mm, hot-sealed at the top. One ton jumbo bags are available with a discharge spout. For dealers we print neutral bags or your own label, with your brand, your analysis and a QR code linking to the batch COA. Loading is done on pallets with stretch wrap; a 20ft container holds 25 tons net without pallets or 22 tons on pallets.

Before shipment we keep a 500g retained sample from the lot, seal it, and photograph the seal and lot number. A third-party inspection through SGS or BV can be arranged at Qingdao on request at cost. Typical documents we release with each shipment are the COA, packing list, non-wood packing declaration and a phytosanitary-free statement for mineral fertiliser. If your laboratory disagrees with our COA on arrival, we will retest the retained sample and negotiate against the original sealed sample, not against a photo.