Robinson, J. B. D., <br/><br/>
The soil nitrogen index and its calibration with crop performance to improve fertilizer efficiency on Arable soils 
J. B. D. Robinson 
 - Slough, England  Commonwealth Agricultural Bureaux  1975 
 - 53 pages;   25 cm. 
 - Special publication  no.1 .
<br/><br/>p. 47-53 
<br/><br/><label>ISBN: </label>0851983405 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Soils--Nitrogen content<br/>Nitrogen fertilizers<br/>Nitrification<br/>Soils--Analysis