Thus, pesticides may be used to aid in controlling weeds, insects, other pests, and plant diseases that interfere with this production. By reducing the need for tillage to control weeds, herbicides offer the added benefits of reduced erosion and reduced fuel consumption with, consequently, less greenhouse gases produced. Now a National Pesticides Sales Database is being prepared by Health Canada's Pest Management Regulatory Agency, supported by data from the Crop Protection Institute. Pesticide use Many, but not all, pesticides are applied to soil. Some can vaporize from the soil or plant canopy, or be transported as aerosols through the air during spraying.
Pesticides can wash off farmland in surface runoff and enter surface waters.
They can also leach through the soil profile into tile drainage water or groundwater. The amount of pesticide lost from farmland, and how it is lost, is determined by the nature of the pesticide and the amount used weather conditions time elapsed between pesticide being applied and rainfall events physical and chemical properties of the soil slope of the field crop production practices. In the past, pesticides were often highly toxic, persistent, or both, posing great concern for human and animal health. Today's pesticides are generally less toxic, more specific, and less persistent, but their presence in water is still a concern and safe limits are not always known.