Nutrient performance indicators for the Australian grains industry

IPNI in collaboration with Southern Farming Systems (SFS) and GRDC, conducted a benchmarking project to identify how efficiently farms in the southern grain growing regions are utilizing N, P, K, and S. This project aims to develop and test a process to identify nutrient use benchmarks using partial nutrient balance (PNB) and partial/total factor productivity (PFP) against which growers can assess their nutrient management practices. The project will provide us with important information to start a dialogue with growers and industry representatives about the issues that arise from inefficient nutrient use and allow us to identify areas of potential improvement.

We have collected over 2,500 paddock records of fertilizer use and crop yields. These data were compiled into sequences of at least four years to estimate paddock-scale nutrient balances for N, P, K, and S. The inclusion of legumes and pulse crops meant estimates were made of N fixation which were included in the balances. This is the first time such data sets have been compiled in this region and will become a template for future data collection based on the project in IPNI Brazil, which has developed an on-farm nutrient balance calculator. The results from the survey estimated that the partial factor productivity for these farms were 84 (N) and 218 (P), but the values for K and S were considered unreliable as there is little fertilizer K or S used so the denominator for this metric is very small or zero. The field-scale PNBs were 1.8 for N and 0.82 for P. Of interest is that the PNB for P derived from these data is consistent with the value derived from the national data set and published in the Global Partnership for Nutrient Management report published in 2015.

The data from this survey will also provide regional information on fertilizer use by crop. These data will be presented at the 2016 International Nitrogen Conference in Melbourne, Australia.