00317nam a2200109Ia 450000500170000000800410001708200120005810000180007024500630008826000480015130000080019920260224040834.0260224s9999||||xx |||||||||||||| ||und||  a631 LOO  aLoomis, R.S.  0aCrop ecology: productivity and management in agricultural   aNew York: Cambridge: University Pressc1998  a538