Explain the following :
i. The year 1921 is known as the 'demographic divide'.
ii. The period during the years 1951 - 1981 is often referred to as the period of 'population explosion'.
Despite tank irrigation being a simple form of irrigation, it is not used by all farmers. Explain Why.
i. Today the need to conserve water resources has become greater that ever. Explain.
ii. Mention two steps that need to be undertaken for the conservation of water resources.
i. What geographical conditions are required for the growth of wheat?
ii. Compare wheat cultivation in India and China - with reference to the varieties grown .
i. It requires 10 C at the time of sowing and 15 - 20 C at the time of ripening. It requires avearge 50 -70 cm rainfall annually.
ii. India
It is sown in the last week of Ocotober/November. The varieties are Kalyani, Sona, Sonalika.
China
Seeds are sown in autumn and harvested in spring. Varieties include Huang He basin, Spring wheat