European Fertiliser Blenders Association
Following the EFBA Quality Handbook enables blenders to manufacture consistent, high-quality products that enable growers to realise the benefits of prescription nutrition in practice.
Nutrient segregation is the biggest potential problem associated with blended fertilisers and it is imperative to minimise risk. Segregation is defined as:
In blends, different granules can contain different nutrients or different proportions of the same nutrient. If not handled properly, segregation can lead to variations in nutrient analysis if it occurs during production or uneven distribution of nutrients applied if it occurs during spreading, both or either of which could impact crop yield and quality.
Segregation can also occur in complex compound fertilisers if they have a wide range of granule sizes, which can also lead to uneven distribution of product during spreading.
| Verbal Notation | Physical Dimension [1] | Target | Tolerance |
|---|---|---|---|
| Mean Particle Size | d50 (in mm) | 3.25 mm | +/– 0.25 mm |
| Fine Particles | < 1 mm | 0% | 0.25% |
| Course Particles | > 5 mm | 0% | 1.00% |
| Main Range | 2.5 – 400 mm | 90% | +/– 5% |
| Granulometrics Spread Index [2] | GSI : ((d84-d16) x 100) / (2 x d50) <18 | ||
[1] It is assumed that the sieve analysis is carried out according to CEN, European Standard EN 1235/AI.
[2] Formerly known as average ranger size variation.
EFBA recommends the use of these 7 sieves (5, 4, 3.55, 3.15, 2.80, 2.50 and 1 mm)
