Phosphate fertiliser source—Gunningbland NSW 2009 to 2012

Abstract

Key findings • High-analysis granular fertiliser (MAP) was the most profitable P source. • Liquid forms of P performed well, but high purchase price reduced profitability. • Rock phosphate did not improve grain yield (averaged over three years) or residual soil P. • Additional biological inoculants applied to rock phosphate did not significantly improve response greater than MAP. • Consider long-term implication of P fertiliser source and application rate. If P rates are reduced, the residual soil P benefit will also be reduced. • Growing season rainfall will impact crop response to freshly applied P. • Growers must consider fertiliser effectiveness and cost ($ per unit of P) when considering P fertiliser source. • It was more profitable to apply no fertiliser than apply rock phosphate.