In Bangladesh about 52 percent of the work force are engaged in the agriculture sector, which contributes about 21 percent to the gross domestic product. This indicates a very low labour productivity. It can be enhanced through increased use of agricultural machinery. High yielding varieties cover more than 80 percent of the production of rice, wheat, maize and potatoes. Use of fertilizers and agrochemicals are increasing every year. Water pumping for irrigation was first mechanized and, at the present time, 55 percent of the cultivable area is under irrigation, mainly by pumped groundwater. The next operation that has been mechanized is the tillage operation mainly done by power tillers (single axle hand tractor) as the average farm size is very small. At present about 80 percent of the land preparation is by power tillers and tractors. The next operation that is being rapidly mechanized is threshing. Farm power availability was only 0.24 kW/ha in 1960, which has increased to 1.05 kW/ha in 2006. It is expected that the power will continue to increase further at a faster rate as there are many important agricultural operations that are yet to be mechanized. Due to various reasons, the degree of mechanization as well as contribution of agriculture to gross domestic product varied in different regions. With the increase of farm power availability and fertilizers, the yield of crops continued to increase. Engines of shallow tubewell pumps are also widely used to power country boats, small three wheelers, rice mills, etc. Power tillers are used to some extent for haulage, but tractors are mainly used for this purpose.