00459nam a2200157Ia 4500008004100000082002000041100001900061245007000080250000600150260004800156300000500204650002500209650002500234700002200259700002000281140316s9999    xx            000 0 und d  a630.277bCON/CR  aConnor,David J  aCrop ecology: productivity and management in agricultural systems  a2  aCambridgebCambridge University Pressc2011  a  aAgricultural ecology  aAgricultural systems  aCassman,Kenneth G  aLoomis,Robert S