Strategies to reduce nitrous oxide emissions from nitrogen fertiliser applied to dryland sorghum. Part 1. Effects on crop production and gross margins

Abstract

Key findings • Fertiliser nitrogen (N) rates should be tailored to suit paddock history and soil mineral N levels at sowing. • Sorghum yields without N fertiliser, although high in a favourable season, were still well below those achieved using additional N fertiliser. • At Tamworth, in-season rainfall ideally suited a split-N application strategy resulting in the highest yields. • At Breeza, drier conditions meant that neither split N application nor slow-release N products boosted grain yields above those reached using urea all applied at sowing. • Gross margins for most alternative N strategies were greater than that achieved when no N was applied.