What soil information do crop advisors use to develop nitrogen fertilizer recommendations for grain growers in New South Wales, Australia?

The Australian grains industry relies on mineralized nitrogen (N) from soil organic matter and plant residues, but fertilizer N is increasingly needed to optimize yields. Most farmers are guided on N fertilizer requirements by commercial crop advisors. We surveyed ( n  = 132) and interviewed ( n  = 11) New South Wales grains advisors to gauge the usage of soil process understanding, soil data and decision support systems ( DSS s) when developing N recommendations. Soil moisture at sowing, seasonal forecasts, crop rotation, soil mineral N, financial risk profiles and paddock history were all used to prepare N fertilizer advice, but stored soil moisture was most important. Farmer confidence in soil N testing was low due to high spatial variability. Most advisors calculated N fertilizer required for yields within 10%–15% of crop potential, but clients’ attitude to financial risk guided final N recommendations. Conservative growers preferred a low input system, while more reliable rainfall or greater reliance on stored soil water led growers to apply higher N rates to maximize long‐term profits. Advisors preferred “rules‐of‐thumb,” simple DSS s and knowledge of crop growth, to elaborate DSS s requiring detailed inputs and soil characterization. Few used in‐crop N sensing. N decision methodologies need to be updated to account for changes in soil fertility, cropping systems and farming practices. New research is needed to answer practical questions regarding soil N mineralization and N losses associated with alternative N application practices and extreme weather events. Training of new advisors in N processes and DSS use needs to be ongoing.