Updated nutrient response curves in the northern and southern regions of Australia

The Better Fertilizer Decisions for Crops database now has results for over 6,000 field nutrient [nitrogen (N), phosphorus (P), potassium (K), and sulfur (S)] response and soil test results from across Australia. While the data set is comprehensive for wheat in particular, there are gaps remaining for particular crops and underrepresented regions where cropping is expanding. The first part of the study was to develop and present the Grains Research and Development Corporation (GRDC) with an analysis of the gaps in crops, regions, and nutrients, and the field experimental protocols that would be included to fill these gaps.

The scoping study has identified the gaps in functional soil test-crop response relationships for crops of importance in farming systems for the Northern and Southern grain regions. It then prioritized the crop-nutrient combinations from that gap analysis, based on the regional importance of the crop on the dominant soil types, and outlined a targeted research program based on intensively managed sites to deliver the information required. The use of crop bench-marking against more widely grown species and the network of soil types and climate delivered by the inter-regional project team will provide a cost-effective way for improving the confidence of growers and advisors to invest in fertilizers for profitability and sustainability.

The most significant gaps concerned N responses on sorghum (north) and P responses on pulses (chickpea, lentil, faba bean, field pea, lupin) in the south and mungbean and sunflower and maize in the north. There was limited data on K responses in the south on any crops, so additional experiments will be based on the same species that were used for P. Similarly, there were gaps identified for S responses in most crops except wheat. Subject to GRDC approval, the field work will commence in the autumn of 2017.