The big number printed on a bag is usually the organic-matter content, written %OM. It is the share of mass that is genuinely organic matter once water and ash are removed. Dai Viet's pelletised lines are named after exactly that figure — LIEGE 65OM, BIOLAND 68OM, TENAXOR 75OM, KOROR 78OM — so nobody has to guess.
The second figure gets less attention and matters just as much: the C/N ratio, carbon over nitrogen. Too low and it breaks down fast — the plant eats immediately, but little humus stays in the soil. Too high and microbes pull nitrogen out of the soil to do the work, leaving the plant briefly short. Around 10–14 is the balanced band for most perennials.
The third figure is moisture. A 25 kg bag at 30% moisture holds 7.5 kg of water; at the same price and 20% moisture you take home 2.5 kg more dry matter. This is the gap most easily missed when comparing two suppliers on price.
Finally, every figure on a bag must be traceable. The standard number, the conformity declaration number and the fertiliser code printed on the label lead back to the file lodged with the regulator. Where those three are missing, nothing stands behind the %OM figure.
