Keulen, H. Van <br/><br/>
Crop response to the supply of macronutrients / 
H. van Keulen & H. D. J. van Heemst 
 - Wageningen, Netherlands :  Center for Agricultural Pub. and Documentation,  1982 
 - 46 p. :  ill. ;  24 cm. 
 - Agricultural Research Reports ;  916 .
<br/><br/><label>ISBN: </label>902200807X 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Filed crops--Fertilizers and manures<br/>Plants, Effect of nitrogen on<br/>Plants, Effect of phosphours on<br/>Plants, Effect of potassium on