A spreader (100) has material storage means (1) for storing a spreadable material(2), a plurality of spinners (5, 6) adapted to receive the material from the storagemeans and to spread the material (2) on the ground, and a Global Positioning System(GPS) receiver (8) for sensing the position of the spreader (100) and providingan output signal indicative of a position of the spreader to a control means (7).The control means (7) calculates a required pattern and density of material (2)to be spread by the spinners (5, 6) based on a comparison of the actual positionof the spreader (A) to a preferred position of the spreader (I), and controls thespinners (5, 6) in order to obtain the required pattern and density of spread material(2). A method of controlling the pattern and density of material spread by a spreaderis also disclosed.
