The supplies I used for this are HO Scale model train corn stalks, Woodland Scenics Fine turf super glue and Green Stuff.
To make the Cornfield Harvest Markers I start with a 30mm base and fill in the grove in the center and add two mounds made of rolled green stuff.
Then I put eight somewhat evenly spaced holes in it for the corn.
Then I coat the base and sides of the mounds with super glue and sprinkle the turf onto the glue.
Then add glue to the top of the mound and push the corn into the holes
Add a little more glue at the base of the corn and use some more turf to build up the mound
Repeat for the other side and you have a corn field ready to be harvested!