Modern centrifugal fertilizer spreaders offer a working width of 24 up to 36 meters. This sets the highest technical and mechanical requirements for both spreader and fertilizer. The wider the working width is, the more important is the quality of the fertilizer.
How can you recognize a high quality fertilizer?
Centrifugal fertilizer spreaders accelerate the fertilizer granules in less than a tenth of a second to 150 km/h. The powers what thereby effect the granules cause strong mechanical load. Fertilizers, which can not stand these extreme circumstances affect the yield and quality of plant cultures. The physical properties of fertilizers influence significantly the spreading performance and pattern of all spreaders.
Round, smooth, hard and heavy - these are the decisive features of a fertilizer for the optimal spreading:
GRAIN SHAPE AND GRAIN HARDNESS
The rounder and smoother the fertiliser grains, the more evenly and further they scatter. The air resistance here is measured using the Cw value. The lower the Cw value, the better the scattering characteristics and the more resistant the grain becomes against side wind. The harder the fertiliser grain, the less likely it is to break on the spreading disc during distribution. Broken granules produce dust and impair grain size distribution.
The bulk weight of a fertiliser is usually specified in kilograms per cubic metre (kg/m3). The heavy grains can be thrown further than light grains, thus increasing the overlap area of the spread pattern: So the higher the bulk weight, the better the spread quality. Every farmer should know the bulk weight of their fertiliser, especially when it has been blended from different individual components. Some blended fertilisers cannot be spread using shot blasting spreaders.
ABRASION, DUST AND CLUMP FORMATION
The mechanical load of the fertiliser grain during transport and spreading can cause grain abrasion. Resistance against abrasion is an important quality feature. Dust affects spreadability, increases environmental pollution and impairs working conditions. Dust leads to over-fertilisation along the tractor pathways and causes the fertiliser grains to clump together
The grain size of a fertiliser should vary (grain size range) because with the same bulk weight, larger particles fly further than small ones. This improves the spread pattern. One particular attribute of a good mineral fertiliser is when more than 90% of its grains have a diameter between 2.2 and 5 mm.
The better the quality of the fertilizer is, the better the spreading pattern and evenness. To provide each and every plant the same amount of nutrients is a key factor for the development and ripening, which at the end also affects the quality of the harvesting works. It is worth to consider, should we choose a blended fertilizer – which consist of grains with different sizes and shapes – or to buy granulated products. The application of blended fertilizers often cause problems, as the different physical attributes of the different granules make it impossible to reach an even nutrient distribution.
Even spreading pattern – higher yield
Usually the effects of uneven spreading are not visible to the naked eye. Variation coefficients below 25% are barely visible, while the constraints of the yield are already considerable. By the time significant colour differences become apparent, the variation coeffi ient is already more
than 30%. However, losses arise long before the spreading faults are picked up on: In the form of lower yields and quality losses, the environment is unnecessarily affected.
Disadvantages of uneven spreading
• Lower, inconsistent quality (protein and oil content)
• Higher rate of infection for crops
• Lower threshing capacity
• Higher drying costs
• Increased environmental pollution caused by overfertilisation
With a good NPK fertilizer we can spread even 5 nutrients in the same time (e.g. COMPLEX 15/15/15 +7SO3+Zn). This high concentration means that we have to use less fertilizer for the application of a certain amount of nutrients. Every single grain of Borealis L.A.T COMPLEX fertilisers contains all the crop nutrients in the correct ratio. Distribution mistakes caused by separation are therefore excluded.
The traded fertilizer types are repeatedly tested in spreading halls and the here ascertained adjustment values are fixed in the spreading adjustment manuals. The fertilizers those values are given in the spreader adjustment manuals were tested under sound circumstances. Unfavourable weather or storage conditions change the spreading features of the fertilizer, therefore some deviations from the given adjusting values can be necessary. A good spreading pattern shows a flat spreading curve with big overlapping areas. So is the multi-overlapping
possible, and distribution mistakes can be widely avoided. This can be just judged with the mobile test tray set.