The Punjab Agriculture Department (PAD) has advised farmers to remove weeds from their field because they can cause 20 to 45 percent reduction in per acre yield of spring crops, such as maize, sunflower or sugarcane. The advisory has urged them to keep their fields clean during first 40 to 45 days of sowing of their spring crops. "These weeds also have the capability of using two to three times more of these nutrients than the crops itself," it warns.