Research project NM/A/11 (Research action NM)
CONTEXT
For economic and environmental reasons, the agriculture has to use fertilisers with preciseness. So, it is necessary, that fertilisers present a constant and well-defined quality. Among fertilisers, the bulk blend allows to obtain composed formulation, but with components having physical differences, they often present segregation. The knowing of the physical characteristics of fertiliser particles is essential to analyse their behaviour.
THE PROJECT
The works concern:
- the development and definition of the measuring methodology of these characteristics,
- the bringing out and quantisation of the influence of these characteristics on the fertilisers behaviour when handling and spreading bulk blend.
At the end, it will allow to define quality thresholds for these criteria and therefore, lead to a more efficient use of an improved product.
The whole work to be carried out can be divided into two stages:
1. The development and definition of the measuring methods of the fertilisers physical characteristics
Successively, existing or improved methods must be tested with the reference fertilisers. From the results obtained, potential modifications will be introduced in order to improve the precision, reliability, repeatability and setting up easiness of the measurements. The characteristics being the object of researches are the sphericity, friability and impact test. This stage allows a better knowledge of the properties of the particles.
2. The analysis of the influence of the fertilisers’ physical characteristics on their behaviour
It is necessary to analyse their influence for different situations as the stocking, the handling, the blending (or mixing) and the spreading.
For all these analyses, excepted the spreading, it will be necessary to design an experimental equipment able to simulate the real conditions in order to master at the best the influence of the analysed parameter.
The principle is to realise a set of bulk blend of two components and to follow their behaviour and especially the tendency to segregate. For each mix, two fertilisers quite similar, excepted for one particular parameter are selected. Then, with these products, we are able to simulate the different situations (transport, handling, stocking, ...). Among these tests, we use a flow on a plate and in a container. Finally the bulk blends are spread on the field and the homogeneity of the fertiliser is analysed.
THE PARTNERS
There are no partners for this project but subcontractors:
- the Department of quality of the products - CRA for the analysis of the reflectrometry in the near infrared,
- the laboratory of analysis of the state for the determination of the chemical composition of the fertiliser,
- the Laboratory MICA of the University of Liège for measurement of the shape with image analysis techniques.
EXPECTED PRODUCTS AND RESULTS
From researches, test methodologies will be described with the required precision for:
- the flow rate measurement,
- the interpretation of the sieving data,
- the shape determination using the image analysis.
Correlations have been found between the physical characteristics of the particles (elongation-angle of repose, flow rate - angle of repose, ...). The measurement by reflectrometry in the near infrared give good hopes for the determination of the chemical composition.
Definition of quality criteria for the fertilisers
With the blends, the first quality criteria are proposed. The dimension of the particles is the most important parameter. Nevertheless, the shape and the density of the particles have an influence essentially during the spreading. At this stage, here are some recommendations for the fertilisers:
- produce and use fertilisers with a limited granulometric spread. It means that the content of small (< 1 mm) en big (> 4,5 mm) particles must tend to zero;
- promote high flow and use anti-coning devices;
- for the spreading, the shape and density of the blend components must be similar.
SCIENTIFIC COLLABORATION
A collaboration exists for the measurement of the shape of the fertiliser particles with the laboratory MICA of the University of Liège.
USERS COMMITTEE
- G. Houins, L. Marchal, P. Nadin and A. Vandersanden (DG4 Ministry of Agriculture)
- G. Detiège (Phytophar)
- N. Nicolas (Fedagrim)
- J. Engelmann (BASF)
Finally, the results interest:
- spreader’s builders (Rauch, Amazone, Bogballe, Sulky, Kverneland),
- fertiliser manufacturers (BASF, Kemira, Rosier and the dealers: SCAM, SCAR, Brichart),
- blender Associations (European blender Association, Association française des commerçants de mélanges),
- working group CEN/TC 260 about physical properties of fertiliser.
PROMOTER
Yves SCHENKEL
Centre de Recherches Agronomiques de Gembloux
Département de Génie rural
Chaussée de Namur 146
B-5030 GEMBLOUX
Tel: +32 81 61.25.01
Fax: +32 81 61.58.47
E-mail: schenkel@cragx.fgov.be
Les caractéristiques physiques des particules d'engrais: mesure et influence : rapport final
Bruxelles : Politique scientifique fédérale, 2005 (SP1472)
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