A Sprayer for Experimental Application of Fungicides to Cereals.

Abstract

Application of fungicides to small plots in fields of cereals can playa useful part in the study of effects of disease on crop yield. To suit the scale of this work , I have built a sprayer that can be carried and operated by one person. The spray tank holds 4.6 lit res of fungicide. In my work 4 litres is suff icient for one plot of 100 rn",The nozzles are to one side of the operator, along 2.5 m of the boom, so that a plot 5 m wide is sprayed in two swathes from its opposite edges. The sprayer was adapted from one developed by the New Zealand Forest Research Institute for precision spraying of herbicides. The main changes that were made included the use of compressed air in place of CO2 , and a more flex ible , cheaper, tank design. Various mod ifications to the boom included the use of one delivery line to all nozzles , instead of a separate tube to each nozzle, leg stands to protect the nozzles, and a harness to aid precision of application. The spray tank and compressed air source were mounted on an alumin ium alloy "Mountain Mule" pack frame (Figure 1). The 4.6 litre capacity tank was a 26 em leng th cut from 15 cm (outside-diameter) alum iniu m irrigation pipe. The tank bottom was a dis c of plate alurnlnlu rn 1 em th ick welded to U1e pip e, wit h a 20 mm hose fitting fer the outlet. The iid was a similar disc, secured by a nut to a threaded stee l rod passing up through the centre of the tank from the bottom plate. An '0 ' ring in a groov e mach in-