Rfg237 where it drains diagram

Use of mineral fertilizer spreaders

True density - specific grain weight

Low-density fertilizer grains are more sensitive to wind and do not fly as far as high-density grains of the same size. With specifically light grains (1.3 to 1.4 kg / l), such as urea, the weight of the fertilizer grain is the limiting factor for the throwing distances that can be achieved. Medium density fertilizers (1.6 to 1.8 kg / l) are e.g. B. SSA, ASS, DAP, NPK fertilizers. Potash fertilizers, CAN and some NPK fertilizers are specifically heavy at over 1.8 kg / l.

Bulk density

As a rule, it is not the actual density but the more easily controllable bulk density that is used as the fertilizer property in setting tables. The bulk density can be determined on site with a liter measure and a scale. With urea it is about 0.75-0.85 kg / l, with KAS 0.95-1.1 kg / l and with NPK 1.0-1.7 kg / l.


Grain hardness - grain strength

The grain hardness is important in connection with mechanical loads during handling, transport, storage and application. When spreading, the grains are stressed by the agitators in the spreaders and when accelerating through pressure and impact on the spreading disc. If the grain hardness is not great enough, individual grains will be smashed, in extreme cases up to dissolving into dust. As a result, the dosage can fluctuate and the throwing distance is reduced. Particularly with increasing throwing distances, the demands on the grain hardness increase significantly. To maintain the grain structure, the grain hardness must be at least 3 daN, better over 5 daN (Figure 4).