Explain how the type of crops grown determines the need for irrigation.
Kharif crops need more than 150 cm of regular moisture and can hence be grown in areas of low rainfall with the help of irrigation. Crops such as sugarcane require 100 - 150 cm and grown in large quantities in large quantities in Deccan India in areas of low rainfall with the help of irrigation.
i. What is meant by variability of rainfall ?
ii. How does this variability affect agriculture ?
Give a reason for each of the following :
i. Delhi has rain in December - January.
ii. Kolkata has a little rain in Apri.
i. Name two cities in India which have grown rapidly due to in -migration.
ii. What are the two factors that led to the decreasing growth rate of population from 1981 to 2001 ?
The dependency ratio is higher in rural areas than in UIrban areas. Give two reasons to explain why.
Mention two different ways by which modern methods of irrigation are an improvement over the primitive methods.