Effect of nitrogen fertiliser application timing on grain yield and grain protein concentration of spring barley

Abstract There is relatively little recent information regarding the effect of timing of fertiliser N application to spring barley on grain yield and grain protein concentration (GPC) under Irish conditions. The objectives of this work were to examine the effects of a) timing of the first N application to spring barley (at sowing or at crop emergence), b) altering the proportion of the total N allocation that is applied in the first of two applications and c) delaying a portion of the total N dose until after the tillering phase on grain yield and GPC of spring barley. Twenty experiments were carried out over four seasons (2011–2014) in the south and south-east of Ireland. Results indicated that there was little consistent difference, in terms of grain yield or GPC between applying the first N at sowing compared to where the initial N application was made at crop emergence. Similarly, altering the proportion of N applied in the first application, irrespective of whether the first application was at sowing or at crop emergence, had little effect on either yield or GPC. Delaying the application of a portion (0.2) of the total N until after the tillering stage also had little consistent effect on either yield or GPC. It is concluded that where the majority of N is applied to spring barley before the end of the tillering stage, altering the timing of applications or the proportion of the total applied in each application will have limited effect on grain yield or GPC.