Crop response to deep placement of phosphorus – Gilgandra 2019

Abstract

Key findings • Drought conditions limited production at Gilgandra in 2019. In-crop rainfall was 10% of the long-term average (LTA). • The application of starter fertilisers containing phosphorus (P) resulted in a large (90%) increases in grain yield, averaged across all treatments. • Significant increases in yield were recorded where deep P was applied at 80 kg P/ha as triple superphosphate (TSP) plus starter P, compared to the control treatment where only starter P was applied as well as the treatment that was deep-ripped and no deep-P was applied. • Results demonstrated that responses to residual phosphorus (as TSP) were still being recorded four years after application. • Phosphorus appeared to be more readily available when applied as monoammonium phosphate (MAP) compared to TSP.