Q.What is meant by agrochemicals ? Mention any 2 (Two) effects of over usage of agrochemicals.

Agrochemicals (fertilisers and pesticides) boost farm productivity but, when overused, cause water pollution/eutrophication and biomagnification of toxic residues through the food chain.

Agrochemicals are the chemical inputs used in modern agriculture to increase crop yield and protect crops from loss -- chiefly synthetic chemical fertilisers (supplying nitrogen, phosphorus, potassium and other nutrients) and various pesticides (insecticides, herbicides, fungicides, rodenticides) used to control organisms that damage crops. Overuse of these chemicals, however, carries significant environmental costs. Excess fertiliser applied to fields that is not taken up by crops washes off (runs off) into nearby rivers, lakes and ponds, causing eutrophication: the sudden nutrient enrichment triggers explosive algal/plant growth, and when this excess biomass dies and decomposes, the process consumes large amounts of dissolved oxygen in the water, leading to oxygen depletion and mass die-offs of fish and other aquatic organisms. Overuse of pesticides, particularly persistent, non-biodegradable compounds such as DDT, leads to their accumulation in soil and water and their entry into food chains; because these chemicals are not readily broken down, their concentration increases at each successive trophic level (a phenomenon called biomagnification), reaching toxic levels in top carnivores (such as fish-eating birds, whose eggshells were fam …