$(a)$ Use of fertilizers for a long period causes soil pollution. Explain it.
$(b)$ Water pollution leads to soil pollution. Justify this statement.

(N/A) Excessive use of fertilizers and pesticides over a long period leads to soil pollution in the following ways:
$(i)$ It kills useful soil microorganisms,such as nitrogen-fixing bacteria and earthworms,which are essential for maintaining soil fertility.
$(ii)$ It destroys the natural soil structure and alters the soil $pH$,making it either too acidic or too alkaline,which is harmful to plant growth.
$(iii)$ It leads to the accumulation of toxic chemicals,causing biological magnification in the food chain.
$(b)$ Water pollution leads to soil pollution through the following processes:
$(i)$ Irrigation with contaminated water: When water bodies are polluted with industrial waste or sewage,using this water for irrigation deposits toxic heavy metals and chemicals directly into the soil.
$(ii)$ Run-off and leaching: Pollutants present in water bodies can seep into the groundwater or be deposited on land during floods,thereby contaminating the soil profile.