• Biological — in some crops, insects will eat certain weeds and in others, livestock grazing helps, but those methods don't work in row crops. (sciencedaily.com)
So the orchard experts purposefully plant certain weeds around trees and let them grow as much as they want. (redeeminggod.com)
«Also, certain weeds occur only at certain times of the year and that information can be integrated into the models.» (today.agrilife.org)