Blends require extra attention when spreading and adjusting spreading patterns

A blend is a combination of fertilisers. Applying blends is a good addition for customising the way particular plots are fertilised. However, spreading them does require additional attention. A good blend fulfils a number of requirements for ensuring proper distribution of all the granules.

Fertilisers are regularly supplied in the form of blends. You can choose to buy blends ready-made or to blend the fertiliser yourself. OCI’s fertilisers Nutramon and Granular3 are high-quality components for producing blends. Due to the even granule size distribution, hardness and specific gravity of these fertilisers, it is possible to make homogeneous blends with good spreading properties.

Pros and cons of blends

Using blends has advantages, although there are a few issues to consider.

Advantages

• Nutrient composition can be tailored to crop requirements;
• Reducing the number of working passes.

Issues to consider

• Spreading, especially on larger working widths, requires extra attention and adjustment;
• Quality of the blend depends heavily on the added components and proper blending;
• Timing of application versus nutrient efficiency in relation to crop requirements.

A good blend has a unique quality

Storage and distribution have a major impact on the ultimate quality of blends. Individual granules (with different properties) in a blend tend to separate during storage and handling. This segregation (or demixing) is particularly prevalent in blends with high fractionation and can cause serious inaccuracy in the spreading pattern. The spreading pattern is determined by the quality of the blend and the working width. Spreading over a less wide area reduces the chances of skewing the spreading pattern. Moreover, demixing occurs not only during distribution and storage, but also while the fertiliser spreader is being used, resulting in the incorrect distribution of the various nutrients across the field.

Requirements for a blend

The main requirement for a blend is that the physical properties (density, fraction distribution, granule size, hardness and granule shape) should be the same so as to prevent demixing.
Besides physical properties, the chemical properties of the fertilisers used in a blend are another important factor. It should be possible to create a blend based on chemical properties. Avoid cross-reactions, which will make the blend go hard.

Our advice from a quality and spreading point of view is that a ready-to-use blend is the preferred option. If you do want to make your own blend, always consult a compatibility chart before mixing fertilisers!