Herbicides: types and varieties, general information
Herbicides: selective and nonselective, contact or systemic action.
Herbicide is chemical compound that kills plants or inhibits their normal growth. A herbicide in a particular formulation and application can be described as selective or nonselective. In agriculture in Saskatchewan, selective herbicides are often used instead of tillage to protect crops against the weeds or in combination with tillage and other agronomic practices, to control weeds without damaging crops. For these low-till or no-till systems, scientists are using biotechnology to develop crop varieties with increased tolerance for herbicides. Nonselective herbicides, toxic to all plants, are used where complete control of plant growth is required. Contact herbicides kill only the parts of the plant they touch; systemic herbicides are absorbed by foliage or roots and translocated to other parts of the plant. Some herbicides, mixed into the soil, will kill germinating seeds and small seedlings.