The study looked at how using minimal or zero tillage in wheat and corn fields affects crop yields and profits. They surveyed farmers in Ningjin County and found that long-term minimal or zero tillage can lower wheat yields and profits. It's better to plow the fields deeply every 3 to 5 years instead. Comparing wheat/corn rotation with potato/cotton rotation, they found that rotating crops can help improve the benefits of tillage systems in double-cropping areas.