Air boom spreader for particulate material

An air-boom spreader for spreading particulate material on a field, the spreader comprising:

• a hopper for containing the particulate material;
• a metering device comprising a plurality of sluices, the metering device receiving the particulate material from the hopper and partitioning the particulate material into the plurality of sluices;
• a plurality of outlets transversely spaced-apart on a boom in a direction perpendicular to the direction of travel of the spreader;
• and,
• a plurality of air lines connecting the plurality of sluices to the plurality of outlets for conveying the particulate material in an air stream from the plurality of sluices to the plurality of outlets,
• wherein there are more than twice as many outlets as there are sluices,
• and wherein the plurality of outlets comprises an innermost outlet, an outermost outlet and at least three other outlets between the innermost outlet and the outermost outlet whereby the innermost outlet and the outermost outlet are each supplied with half as much of the particulate material as each of the at least three other outlets.