Mechanization is the main facilitator of the trend toward bigger farms. This goes along with another lesson from historical data and contemporary experience: Generalization 6.
Large farms adopt new forms of machinery considerably faster than small farms. Because larger farms offer more collateral, they make it easier to borrow to invest in new machinery.
Primary power sources are many and varied including solar, wind, hydroenergy and geothermal, which may be used to power stationery equipment (wind, hydroenergy), to provide heating or cooling (solar, geothermal) or to generate electricity (wind, hydroenergy) to service a multiplicity of on-farm activities (see also, Energy Sources: Renewable and Non Renewable).
While much remains to be done on small farms in the poorest regions, sufficient progress has been made to accelerate food production in line with population growth (contrary to the Malthusian prediction). In this theme, farm machinery is considered with primary emphasis on engine and motor driven machines and implements and a lesser emphasis on human or animal powered equipment.
Thus, huge savings in labor have accrued from engine-driven mechanization systems in the developed world, which in turn have been rapidly followed by rural depopulation. The societal impact of rural depopulation has not been adequately addressed.