Millet (Hirse) is an ancient grain crop which had come out of fashion long since.
Roman legionaires ate it, the Celts ate it, Germanic and Slavic tribes at last took over the habit of eating millet, in short: millet was the 'bread of the poor' - a most important staple food. Only potatoes and - in warmer regions - maize (your corn in the US) later took over that role.
But it seems that might change. What crops you see here in the pictures is common millet (Panicum millaceum) - except for the sunflowers in the second picture, to the left of the road.
Millet nowadays mostly is used for bird fodder even though it is quite delicious even eaten uncooked (I've tried the ones I photographed here, the ones from the field in the third photo were the best).
But now that most other crops are harvested it only becomes evident how much millet there was sown this year, in and around Vienna. It seems there is still money after all in millet, these days. I just can't believe that this were all bird fodder; however I haven't seen packs of millet in my local supermarket. I don't even know how to prepare millet porridge (the bread of the poor of our family always were potatoes), that knowledge has gone down the drain over the centuries. Probably I should try some day.