Powers, Laura E. <br/><br/>
Ecological principles of agriculture / 
Laura E. Powers, Robert McSorley 
 - Albany, NY :  Delmar Thomson Learning,  2000 
 - xi, 433 p. :  ill. ;  24 cm. 
<br/><br/>Includes bibliographical references 
<br/><br/><label>ISBN: </label>0766806537  RM321.40 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Agricultural ecology