wing and lifting of irrigation water. These operations are done by different sources of power, namely human, animal, oil engine, tractor, power tiller, electricity and renewable energy (biogas, solar and wind). HUMAN POWER Human beings are the main source of power for operating small tools and implements. They are also employed for doing stationary work like threshing, winnowing, chaff cutting and lifting irrigation Water. It is generally believed that there is surplus human power available for agricultural operations in India. According to 2001 census figures, the total Indian rural population is about 74 crores. Of the total rural population only 30 per cent is available for doing farm work. Hence the total number of persons available would be about 74 x 0.30 = 22.2 crores. This figure includes both the landless labourers as well as the owners of farms in the country. On the average a man develops nearly 0.I horsepower (hp.). Therefore, the total power available through human source may be about 2.2 crore hp. But there is a steady decline in the number of landless labourers available for doing farm work in rural areas.