Getting dirt in the combine and in the sample is just seems to be a common problem with all combines when cutting things like peas and lentils and you have to scrape the ground to get them. The vines have dirt on them and the odd clod or two makes it into the header. The problems with screens or holes in places like the feeder house bottoms, elevator bottoms, unloading auger bottoms, ect is that the holes soon get plugged up with the other junk and weeds that are also common in these two crops. Combine is designed to save the smallest stuff and that ends up being dirt. Back in the dark ages an optional rotary screen assembly (Hart Scour-Kleen was one) was used to get out weed seeds and fines and it was placed in the auger going into the grain bin. But I have not seen one of them in years. I read of a guy in Farmshow magazine a few years ago that installed an "aspirator" type cleaner on an CIH AF at the top of the clean grain elevator to suck out the dirt and fines. Keeping the field as smooth as possible and even rolling after seeding helps reduce the dirt problem somewhat.
