A Carbon Dioxide Powered Sprayer for Small Plots 1

EVICES have recently been described by Robinson D and Dunham2 and by Shaw3 for use in applying herbicides and other materials to experimental plots. The sprayer developed by Shaw is described as being particularly adapted to plots of more than a few square feet in size. With this sprayer unikorm rates of application are obtained by moving the closely calibrated equipment at a uniform speed over the area to be covered. Experimental areas available are often small, however, or there may be no gain in precision by using more than rod-row plots. For such conditions a sprayer of the type described by Robinson and Dunham is more adaptable. T o insure accuracy of application the spray material required for each plot is measured and applied separately as uniformly as possible. A sprayer for small plots, utilizing compressed carbon dioxide as a source of pressure, was used successfully at Madison, Wis., during 1949 and 1950. The essential features of the sprayer, shown in Fig. 1, are a 7ounce carbon dioxide cylinder (A), a reducing valve such as is used in inflating tires (B), a knapsack sprayer shutoff valve (C) , a pressure gauge (D), a check valve (E), a spray tank that also serves as a handle grip (F), a filler plug (G), a boom of suitable size (H), and nozzles (I). The spray tanks and fittings are preferably made of brass cr aturninurn to avoid corrosion, but thin wall