NITROGEN USE EFFICIENCY WITH THE APPLICATION OF CONTROLLED-RELEASE FERTILIZERS COATED WITH KRAFT PINE LIGNIN

The aim of the present paper is to assess the efficiency of several ex perimental fertilizers in a soil-plant system, The laboratory-prepared fertilizers consisted of granular urea coated with Kraft pine lignin, Five fertilizers were used with coatings differing in thickness and/o r the addition of linseed oil as a sealing agent, The experiment was c arried out in pots inside a glasshouse, The crop used was rye-grass, R esults were compared with those from a urea control treatment without coating and a soil without fertilizer application. The dry matter yiel d and the hi uptake by the plant were higher in the treatments with co ated controlled release fertilizers (CRF) than in those with uncoated urea, There was a lower nitrogen loss through leaching when using CRF (34 to 68%) was used than when using uncoated urea (over 74%) was used , The N use efficiency was lower for urea than for coated fertilizers, This index increased with the thickness of the coating and the additi on of the sealing agent.