Triazine damage will show as tip burning and possibly watery blotches in the middle of the leaves. If this is the case there will probably be no yield penalty in practice. The residue effect is more severe in a pot than in the field. Sulfonyl ureas Fill pots with soil from the paddock. Use the planned legume or a more sensitive species as the test plant.
Corn is another sensitive species.
Grow the seedlings to two leaves then unpot and wash the soil from the roots. If residues are present, the roots will be shortened and thickened. They will have few or no fine root hairs. It is essential to have good controls with which to compare the roots. Alternatively, the plants can be grown on as for cereals.