(N/A) Major sources of soil pollution are industrial wastes and agricultural pollutants such as pesticides and fertilizers.
It is very important to maintain the quality and fertility of soil to ensure and sustain the growth of plants and food crops.
Insecticides like $DDT$ are not soluble in water. For this reason,they remain in soil for a long time,contaminating root crops. Pesticides like Aldrin and Dieldrin are non-biodegradable and highly toxic. They can enter higher trophic levels through food chains,causing metabolic and physiological disorders. The same is true for industrial wastes that comprise several toxic metals like $Pb, As, Hg, Cd,$ etc.
Hence,the best way to check soil pollution is to avoid the direct addition of pollutants to the soil. Also,wastes should undergo proper treatment. They should be recycled and only then allowed to be dumped.