The Agricultural Engineering Research Unit, based at Trangie ARC, undertook a research program to ensure an even and adequate (but not excessive) supply of NH3 to the crop in conditions which allow full utilisation by the crop. By so doing, this would either reduce or eliminate the presence of &quote;striping&quote; in cotton. The research program was initiated in 1989 to (i) determine the level and cause of variability in NH3 flow and distribution from the outlets of rigs, and (ii) modify the NH3 application systems to ensure even flow and distribution.