Weed control methods impact the amount of weed seeds in the soil, the number of weed seedlings, and the yields of corn and soybeans. High initial weed seed density leads to a rapid decrease in giant foxtail seeds under weed-free conditions. Different control methods have varying effects on weed seed numbers. Herbicides can sometimes increase weed numbers if applied in bands, but crop yields remain similar to full-rate herbicides. Low initial weed density results in an increase in giant foxtail seeds over time, while broadleaf species decrease. Weather conditions play a significant role in the effectiveness of weed control methods and their impact on weed populations and crop yields. The relationship between weed control, weed populations, and crop yields is complex and influenced by initial weed density, species composition, control methods, and weather patterns.