Question

distinguish between:
i)pesticide and weedicides
ii)Manures and fertilizers...

Answer 1

1.

Some organisms specifically attack and damage the crops. These organisms are called pests. They may include rats, locusts, etc. Chemicals are sprayed on the crops to kill such pests. These chemicals are known as pesticides.

While, Those chemicals which kill the weeds(unwanted plants) but do not harm the crops when sprayed on fields are called Weedicides.

2.

Wastes of animals and plants can be used as manure to replenish the nutrient defucient soil. Farmers dump animal dung, vegetables and crop wastes at open places and let them be decomposed by bacteria and fungi. After a month or so, the manure is ready and is mixed up with soil before sowing. Manure not only increases the nutrients, but also enhances the water holding capacity of the soil.

While, Fertilisers are chemical sunstances rich in specific nutrients like nitrogen, phosphorus and potassium. Fertilisers are produced in and are easier to store and transport as compared to manures. Being soluble in water, they are readily absorbed by plants. But overuse of fertilisers can change the chemical nature of soil.

Answer 2

i)Pesticides are used to kill pest while Weedicides are used for clearing those unwanted plants that grow in agricultural field who compete with the crops that are grown for water,minerals etc
ii)Manures are organic substances which helps in over all development of a crop while fertilizers are chemical substances which gives particular nutrients to a crop.Manures are environmental friendly while Fertilizers are non biodegradable substances which may pollute water.
Hope it helped thank you