Organic material and soil productivity.   

 - Rome,     1978. 
 - vi, 119 p. :    figs., tabs. ;    28 cm. 
 - Its soils bulletin ;   no. 35. .
<br/><br/>Includes bibliographical references (p. 101-119). 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Soils.--------