00503nam a2200181Ia 4500008004100000020001500041082001700056100002100073245006500094260004500159300000800204650001400212650002000226653001600246653002600262653001600288653001700304170901s1976    xx            000 0 und d  a0393091678  a338.19bE22L  aEckholm, Erik P. 0aLosing GroundbEnvironmental Stress and World Food Prospects  aNew YorkbW. W. Norton and Companyc1976  a223  aEconomics  aSocial sciences  aAgriculture  aEnvironmental aspects  aFood supply  aSoil erosion