EVERYDAY SCIENCE

Detailed explanation-1: -Herbicides are used in agricultural and wildland ecosystems to reduce the density of weeds and promote the growth of desirable species. Use of herbicides in agroecosystems may change composition of weed populations. In wildlands, herbicides may increase the diversity of native species.

Detailed explanation-2: -Postemergence herbicides are used to control weeds that have already emerged. The younger the weed, the better a postemergence herbicide will work.

Detailed explanation-3: -Overview. Herbicides are chemicals used to manipulate or control undesirable vegetation. Herbicide application occurs most frequently in row-crop farming, where they are applied before or during planting to maximize crop productivity by minimizing other vegetation.

Detailed explanation-4: -Herbicide reduces the cost and drudgery in weed control. Reports show that herbicidal weed control is much cheaper and gives three to four times much more net benefit than manual weed control. Thus weed control by herbicide has clear economic advantages over manual and mechanical weed control.

Detailed explanation-5: -Herbicides kill plants by causing a build up of a toxic substance, where the toxic compounds stay at reasonably low levels. By inhabiting the target site (enzyme), herbicides cause substances to build up and damage the plant. This is how the herbicide glyphosate works.