Healthy soil and sustainable growing

["Tradingpost" <tradingpost@lobo.net>]

   Given current depletion rates of land, water, and energy resources, U.S. 
agricultural productivity is already unsustainable. Should the U.S. 
population double within the next 60 years, the subsequent decrease in arable 
land will substantially change American eating habits and dramatically reduce 
future food exports. ..
   Land: On-going soil erosion and expanding urbanization contribute to the 
continuous loss of cropland in the U.S. Annually, more than two million acres 
of prime cropland are lost to erosion, salinization, and waterlogging. In 
addition, more than one million acres are removed from cultivation as 
America's limited arable land is Overwhelmed by the demands of urbanization, 
transportation networks, and industry. As a result of arable land shortages, 
U.S. meat consumption may be reduced.
   Water: The groundwater that provides 31% of the water used in agriculture 
is being depleted up to 160% faster than its recharge rate. The vast U.S. 
Ogallala aquifer (under Nebraska, Oklahoma, and Texas) will likely become 
non-productive within the next 40 years. Even if water management is 
substantially improved, the projected 520 million Americans in 2050 would 
have about 700 gallons/day/capita, considered the minimum for all human 
needs, including agriculture.
   Energy: The availability of non-renewable fossil energy explains in part 
the historically high productivity of U.S. agriculture. Currently the 400 
gallons of oil equivalents expended to feed each American amount to about 17% 
of all energy used in this country each year.

- From FOOD, LAND, POPULATION and the U.S. ECONOMY by David Pimentel of 
Cornell University and Mario Giampietro Istituto of Nazionale della 
Nutrizione, Rome
http://www.dieoff.org/page40.htm