Precise spreading

Precise spreading

According to the ‘Theory of Minimum’ all nutrients need to be available in the right proportions. Therefore, a homogeneous nutrient distribution is crucial for high nutrient use efficiency and high yields. Only COMPLEX fertilizers containing all nutrients in each granule can ensure the best nutrient distribution in the field and thus maximize yields. 

Figure 1: Figure: Twenty-three field trials with different crops in Germany, Austria, Belgium, Denmark and France (1988-1992) show higher yields with COMPLEX compound fertilizers compared to blends. On average 400 kg more yield per hectare with COMPLEX fertilizers was achieved. Ref: E. Schöningh, Limburgerhof, BASF, 1993

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Figure 1
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Unlike mixed/blended fertilizers, COMPLEX fertilizers do not get segregated when being stored, transported to the field and spread. Segregation leads to uneven spreading, and nutrition disparities. The difference can be up to 30 to 40% variation in mixtures with different physical properties. Irregular spreading is made visible by alternate light and dark strips in the field, which lead to yield losses. Furthermore, the compound fertilizer facilitates a denser distribution (more granules per plant) in the field compared to fertilization with straights or bulk blends.

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Uniform distribution depends on even fertilizer output from the disc and overlapping between 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 the curve of the spreading profile is plotted. Spreading regularity is expressed in coefficient of variation (CV), which quantifies the average deviation of doses applied in relation to the mean dose, and is 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 good
  • A CV between 10% and 15% is medium
  • A CV above 15% is poor
PHYSICAL CRITERIA
PHYSICAL CRITERIA
SPREADING PRECISION
SPREADING PRECISION
ALL IN ONE
ALL IN ONE
SPREADER ADJUSTMENTS
SPREADER ADJUSTMENTS
Nitrogen

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 of the plants, and thus a reduction in yield and protein content. Fertilizing more than the economic optimum causes loss in revenue and increases the risk of unproductive nitrogen loss.

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Uneven nitrogen distributions

It is a false assumption that uneven spreading would even out on a field. Higher yields due to more fertilization do not balance the lower yields due to less fertilization because of the flattening dose-response curve. This is true at any yield level and without crop damages. 

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Illustration of the gains and losses due to more and less fertilization than specified (200 kg N/ha). The dose-response-curve flattens; therefore, yield losses (red) are always larger than the gains (green). 

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Phosphorus distribution

Phosphorus is not mobile in soils, which means it remains at the spot where it has been placed after spreading. Consequently, the roots need to grow towards the location where the fertilizer granule dissolved to reach the fertilized phosphorus. Only COMPLEX fertilizers can be distributed homogeneously and facilitate a dense distribution of phosphorus.

Even if an equal distribution of the different compounds in a blend is accomplished, the distribution of phosphorus in the field is still better with COMPLEX fertilizers as illustrated in the example below. 

The nutrient distribution of COMPLEX NPK fertilizers is better, even if bulk blends do not segregate during handling, transportation and spreading. Each of the five complex granules contains phosphorus but only one in the blend. This means that fertilizing 300 kg COMPLEX 20/10/8 per hectare the average distance between the applied phosphorus is 4.6 cm whereas the distance between the DAP granules in a blend is 10.3 cm. 

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The phosphorus distribution of COMPLEX 15/15/15 +7SO3+Zn is much denser than that of straights (DAP or TSP). Fertilizing 100 kg of P2O5 per hectare places 10.4 COMPLEX granules per dm2 with an average distance of 3.1 cm while only 3.4 granules of DAP with an average distance of 5.4 cm are placed per dm2.

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Physical properties of fertilizer granules

Excellent physical quality is essential for precise spreading. Borealis L.A.T is dedicated to delivering the best quality. 

The physical characteristics of granulated fertilizers have a significant influence on the spreading pattern by affecting the behavior 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.

The spreading of granules comprises several stages:

  • 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.


PHYSICAL CRITERIA

The physical characteristics of granulated fertilizers from Borealis L.A.T are optimised to protect them during storage and allow precise and even spreading. 

The term physical quality encompasses many properties that have an impact on spreading; density, sphericity, hardness, mean diameter, grain size distribution, dust rate, resistance to humidity reabsorption. 

That means that physical quality is an essential requirement.

Borealis L.A.T guarantees superior and consistent physical quality across our entire product range.

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Spreader settings
To ensure precise spreading and thus even distribution for effective nutrition, it is crucial to adjust the spreader correctly. The fertilizer ranges from Borealis L.A.T are referenced for spreaders from major manufacturers.
Information about the factory origin is also provided. 
Based on the information provided on the bags (before the batch number) in manufacturer’s databases, the origin is specified as follows:
  • “GP” for Borealis Grandpuits
  • “GQ” for Borealis Grand-Quevilly
  • “OTT” for Borealis Ottmarsheim
  • “St.-Peter-Straße 25, 4021 Linz” for Borealis Linz

Note that the manufacturing plant is also stated on the documents accompanying the product.