Powers, Laura E creator Mc Sorley, Robert text xx Africa] Delmar 2000 9999 monographic und xi, 433p: ill. Ecological principles of agriculture will help in understanding the ecological principles operating in any agricultural system. Everyone will findit invaluable as a general overview of ecological principles especially as they relate to agricultural practi Laura E Powers Agricultural ecology; Agriculture 630.27721 P888E 0-7668-0653-7 99-043250 NITIL 190327