Once you have done as czechrott said "conditioned" the puppy to seek for the treats amongst the grass, hereby using its scenting ability to find the food, you can also form a "scent pad" by stomping the ground beneath your feet and sprinkling some food then take a "leap" to another spot, once again shuffle your feet, sprinkle food and do this a third time. Let the puppy seek the food moving from pad to pad hereby reinforcing the association of the food with the "disturbance" on the ground. On the last pad take the puppy away when say 50% of the food is still left. By doing this the puppy leaves while still wanting more and will even be more eager next time around. Do say 300 of these exercises
and then move onto short tracks.;)