International soil fertility manual  
/ Potash & Phosphate Institute 
 - U. S. A.:   Potash & Phosphate Institute,   1995 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Agriculture 
<br/><br/><label>Subjects--Index Terms: </label>Nitrogen  Phosphorus  
<br/><br/><label>Universal Decimal Class. No.: </label>631.452(100)   / N5