Nitrogen (N) contributed by legumes is an important component of N supply to subsequent cereal crops, yet few Australian grain-growers routinely monitor soil mineral N before applying N fertiliser. Soil and crop N data from 16 dryland experiments conducted in eastern Australia from 1989-2016 were examined to explore the possibility of developing simple predictive relationships to assist farmer decision-making. In each experiment, legume crops were harvested for grain or brown-manured (BM, terminated before maturity with herbicide), and wheat, barley or canola were grown. Soil mineral N measured immediately before sowing wheat in the following year was significantly higher (P<0.05) after 31 of the 33 legume pre-cropping treatments than adjacent non-legume controls. The average improvements in soil mineral N were greater for legume BM (6016kgN/ha; n=5) than grain crops (3520kgN/ha; n=26), but soil N benefits were similar when expressed on the basis of summer fallow rainfall (0.15 +/- 0.09kgN/ha per mm), residual legume shoot dry matter (9 +/- 5kgN/ha per t/ha), or total legume residue N (28 +/- 11%). Legume grain crops increased soil mineral N by 18 +/- 9kgN/ha per t/ha grain harvested. Apparent recovery of legume residue N by wheat averaged 30 +/- 10% for 20 legume treatments in a subset of eight experiments. Apparent recovery of fertiliser N in the absence of legumes in two of these experiments was 64 +/- 16% of the 51-75kg fertiliser-N/ha supplied. The 25 year dataset provided new insights into the expected availability of soil mineral N after legumes and the relative value of legume N to a following wheat crop, which can guide farmer decisions regarding N fertiliser use.