Senior Expert with over 15 years of experience in the fertilizer industry
Uniform distribution depends on an even
fertilizer output and consistent overlapping between the two passes (out
and back) of the broadcasted fertilizer granules.
To test the regularity of fertilizer spreading, the actual dose of fertilizer spread over the projecting distance is measured and then plotted. Spreading regularity is expressed as "coefficient of variation (CV)", which quantifies the average deviation of doses applied in relation to the mean dose. The result is then stated as a percentage. CV, as defined in European Standard 13739, is the ratio between the standard deviation and the mean total distribution.
The lower the CV, the better the distribution. The quality of fertilizer distribution is expressed as follows:
A CV between 0% and 10% is excellent
A CV between 10% and 15% is good
A CV between 15% and 20% is poor
A CV above 20% is unacceptable
Imprecise spreading can have serious consequences. It is often visible in strips or waves, showing 30% over or under-dosing. Uneven and imprecise distribution of fertilizer leads to nutrition deficiencies in the plants, resulting in yield and protein reduction. Too high a dose than the economic optimum, causes a loss in revenue and increases the risk of nitrogen loss.
In windy conditions, prilled AN cannot be spread up to 36m with a correct CV, uneven application will lead to a yield loss. At 36m, only granular AN offers a good to excellent CV, even in windy condition.
The physical characteristics of granulated fertilizers have a significant influence on the spreading pattern by affecting the behaviour of the granule in the spreader and the way it travels through the air. It is important that these properties do not alter during storage.
The evenness and precision of spreading depends directly on the quality of the fertilizer. Particularly when applied with broadcast spreaders at wide working widths, the fertilizer must have clearly defined and consistent physical characteristics.
Borealis L.A.T is dedicated to delivering the best quality.
The spreading of granules comprises several stages that involve a large number of parameters:
Descent of fertilizer into the hopper
Catching of fertilizer by the blades
Fertilizer travelling along the blade
Ejection of fertilizer at a given angle and speed
Ballistic flight of fertilizer granules
In each of these five processes, the physical characteristics of the fertilizer play a major role.
Up to 25km/h
More than 19 days
Compared to prilled products, Granular AN from Borealis L.A.T offers a
better coefficient of variation (CV) at all spreading widths and at all
wind speeds. In windy conditions prilled AN cannot be spread up to 36m
with a correct CV and uneven spreading will lead to yield loss. At 36m,
only Granular AN offers a good CV even in windy weather.
At 25 km/h crosswinds the tests show that Granular AN 33.5 still maintains a good spreading pattern and a correct CV, unlike the prilled products. This unique benefit of Granular AN is giving the farmers confidence to go out spreading while achieving good results.
3 times more days of applications in the spreading season is only
assured by Granular AN 33.5. UK weather makes the farmers work schedule
hard to maintain consistently. During the high season there are only 6
days with wind speeds below 15km/h, but with Granular AN farmers can
spread confidently an additional 13 days when the wind speed is up to 25