00348nam a2200121Ia 4500008004100000082002100041100002700062245003700089260002900126300001500155600002100170650003500191140224s9999    xx            000 0 und d  a633.002:581.1 M0  aCarlson, Peter S., ed.  aThe biology of crop productivity  aNew YorkbAcademicc1980  axvii,471p.  a Peter S.Carlson  aCrop yields,Plant productivity