chemicals in start helps to good productivity of crops of any type but extensive use of chemicals make soil less fertile and finishes its nutrients this causes arid soil.
Generally they are used for avoiding any insects to cause damage to the crop. But now-a-days the chemicals are becoming stronger so as the insects. and the results are faced by humans.
Chemicals used in agriculture has lead to decrease in numbers of many species of birds and has brought them on the brink of extinction, most notably of vultures that are considered as nature's scavengers and control the population of many other species of smaller birds, thus maintaining the natural balance of ecosystem!
I agree with the views of the members,especially, very well explained by Kalyani.The adverse effects of chemicals are also responsible in tampering the texture of soil,normal growth of crops and it indirectly effects the human beings too...!
Manure is more useful to agriculture than chemical.But due to lack of it fafmers are using chemacals as they have no pet animals ,they are using tractor to crop.
the medicine which is used for agriculture, if that is given in less doss it is a medicine if else if it is given in over doss then it is a poision to the agriculture