An agricultural seeder or fertilizer having a meter device which dispenses seed or fertilizer to a plurality of ground-engaging members. The supply of metered seed or fertilizer to each of the ground-engaging members is controlled via input from a GPS/GNSS satellite navigation system to prevent the meter device delivering seed or fertilizer to selected of the ground-engaging members which would otherwise pass over soil which has been previously seeded or fertilized. Raising means, responsive to input from said GPS/GNSS satellite navigation system detecting that the device is travelling or is about to travel over areas of soil that has been previously seeded or fertilized, is further is provided to raise the selected ground-engaging members to which delivery of seed/fertilizer has been prevented in order to prevent soil which has been previously seeded or fertilized from being disturbed. A method of operating a seeder/fertilizer implement to achieve the aforesaid is further disclosed.