Joshi, O.P.Hameed Khan, H.Biddappa, C.C.Manikandan, P.2014-06-102014-06-101985-12Journal of Plantation Crops 13(2) : 88-95 December, 1985http://hdl.handle.net/123456789/2669Laboratory incubation studies revealed that blending urea with retted and unretted coir dust resulted in inhibition/immobilization of urea nitrogen. Blending of urea with unretted coir dust in 1: 1 proportions resulted in accumulation of NH4+-N and retted coir dust in the same proportion led to lowest production of NH4+-N. During the incubation period NOj -N appeared to be withdrawn from the system in urea blended with unretted coir dust (1:1) treatment, whereas its production was lower in the case of other combinations of urea with retted (1: 1 and 9 :1) and unretted coir dust (9:1) compared to urea. Production of total mineralised nitrogen was consistently lowest when urea was blended with retted coir dust (1: 1). Unretted coir dust (1:1) produced lower mineralised nitrogen than urea alone and the other blendings with lower proportions of retted and unretted coir dust (9: 1) showed intermediate behaviour. The results indicated the usefulness of blending urea with coir dust for controlled and gradual release of urea nitrogen. It has a bearing in the fertilizer programmes for perennial plantation crops largely grown in soils prone to heavy leaching losses.enArticle