During the ninety years until 1970, land-labor ratios increased in all countries, especially after 1950. These increases reflect the rapid declines in agricultural labor forces as people moved to industry and off the land.
The United States, however, had an increase in agricultural land as well as a reduction in the agricultural labor force, so that differences in land-labor ratios between it and other countries increased.
Human and animal powered mechanization systems (Figures 2 and 3) are described in detail in Human and Animal Powered Machinery, EOLSS on-line, 2002. The drudgery, long hours and low pay typically associated with these systems make rural life in the developing countries an unattractive career for young men and women.
At first glance, renewable fuels are attractive from an environmental and sustainability perspective and cogent arguments have been made that such considerations justify the generous tax remission protocols necessary to commercialize these products.
For example, the use of renewable fuels in urban vehicles may be justified if the emissions are much cleaner than those from conventionally fuelled vehicles.As a consequence, the transition to engine powered mechanization is likely to occur sooner rather than later in the poorer regions unless rural life (especially for females) can be made more attractive.
Furthermore, workers in greenhouses are employed in a much more comfortable and hospitable environment than field workers and as such the pressure to mechanize is less intense. Looking to the future, harvesting techniques will continue to attract substantial interest and investment in determining if the state-of-the-art technologies (machine vision, robotics, software engineering, GPS and GIS) can be successfully applied to harvesting machines particularly in relation to selective harvesting and the harvesting of delicate produce for the fresh market.