On-farm research manual :   cropping systems research / 
Department of Agriculture - Bureau of Agricultural Research. 
 - xvi, 215 pages :  illustrations, graphs ;  26 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Crops--Research--Philippines.<br/>Farm management--Philippines.<br/>Agricultural systems--Philippines.
<br/><br/><label>LC Class. No.: </label>S 602.5  / .B9521 1990