A nursery sprayer with the recycling principle

A nursery sprayer based on a recycling principle was developed, constructed and then compared to a conventional tractor sprayer. With the recycling sprayer, pesticide suspension is more precisely directed onto the seedlings than with the conventional sprayer. During pesticide application on pine (Pinus sylvestris) seedlings with the recycling sprayer, between 40–90% of the pesticide is collected back into the tank. With the recycling sprayer, a smaller amount of pesticides is needed for equal spray coverage to that of the conventional tractor sprayer. Thus, the recycling sprayer reduces the costs of pesticide and also minimizes the contamination of the ground. However, the boom reach is shorter and therefore it takes longer to treat a given area resulting in a final cost that is equal or higher than with a conventional tractor sprayer. The occupational hygienic survey as well as biological monitoring revealed that the exposure of workers to pesticide did not differ during the recycling spraying and the conventional spraying. The exposure of the workers to pesticides were low with both spraying methods tested. The greatest contamination of protective clothes occurred while repairing the sprayers.