Statistics of crop responses to fertilizers 

 - Rome :  Food and Agriculture Organization of the United Nations,  1966 
 - viii, 112 p. :  ill. ;  23 cm. 
<br/><br/>p. 66 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Fertilizers--Mathematical models<br/>Fertilizers--Economic aspects<br/>Crop yields