Nutrient balances and the need for fertilizers in semi-arid and arid regions :  proceedings of the 17th Colloquium of the International Potash Institute held in Rabat and Marrakech, Morocco. 

 - Bern :  The Institute,  1983. 
 - 394 p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Fertilizers.<br/>Arid regions agriculture.<br/>Soils and nutrition.