question on sunflowers

I have 2 fields of sunflowers, next to each other,,, I dont plant either, the sunflowers just grow. One has 6' tall plants and the field next to it has 18 inch tall plants. It has always been that way. If it is relevant, the one with small sunflowers is also covered in dove weed. Anyone understand this ???

Field A likely has better soil and possible better moisture retention.
Field B flowers get less nutrients due to the competition.
Try plowing field B just after New Years.

Ought to be some good dove hunting.

Thanks, Rickym,,,, I"ll try that next year. Dogcatcher,,, normally great hunts on opening weekend,,, last year - nothing --- also planted some millet this year mixed in with the sunflowers,,, we'll see what happens. I"m just outside of Troy, Tx on I-35.

Probably a soil quality issue