This agriculture extension service publication from Pennsylvania State University discusses techniques and equipment used in spraying field crops. In the discussion of field hydraulic sprayers, specific topics include types of sprayers, tanks, pumps, pressure regulators, hoses, boom spraying, directed spraying, and nozzle bodies. In the discussion of weed sprayer operation, specific topics include sprayer calibration, useful formulae, cleaning sprayer, storing sprayer, and common sprayer troubles. In the third section of this publication, the discussion of air blast sprayers, specific topics include air blast spraying for row crops, operational procedures for air row crop sprayers, and sprayer calibration. (MR)