Foliar N on Wheat

A common question that arises in the cropping season is how much nitrogen is lost when fertiliser, particularly urea, is applied and follow-up rain does not occur immediately after application? One method adopted by growers to reduce the likelihood of volatilisation is to use UAN. There is a perception that a large portion of the nitrogen when applied as UAN is taken up by the crops leaves and that there is a reduced need for follow up rain. Results from this trial do not completely support that idea. The soil applied urea was equally efficient as the UAN and better than the other modes of delivery. Given these results growers can utilise both urea and UAN with confidence that they equally as effective when applied to the soil. As such growers should use the product that they are best equipped to provide the crop both in terms of timeliness and cost. Further work may be required to further assess the efficiency of foliar uptake of UAN and Liquid urea in a non-stressed situation.

TAKE HOME MESSAGES
• Wheat yields from plots where soil applied fertilizers were not significantly different to yields from plots with liquid urea or UAN applied with standard spray nozzles to the crop leaves.
• Both urea and UAN are equally effective when applied to the soil.
• Growers should select the nitrogen product than most suits their farming system in terms of logistics and cost.