THE UPTAKE OF NITROGEN RELEASED FROM SLOW RELEASE N FERTILIZERS BY RADISH, LETTUCE AND CARROT

The effect of slow release N fertilizers and urea was investigated in pot experiment with three vegetables and two rates of applied N. Directly fertilized radish, subsequently grown unfertilized lettuce and third crop directly fertilized carrot were treated by urea as control treatment and by three samples of slow release fertilizers, based on urea formaldehyde condensate, of different solubility.
Availability of N from slow release samples affected yield of growing vegetables and their nitrogen uptake.
Lower availability of N caused lower yields of radish and subsequently grown lettuce mainly on treatments with lower rate of fertilizer compare to urea treatments.
Carrot planted as a third vegetable and directly treated by nitrogen showed higher yield at treatments with less soluble samples due to longer growing period and continuing release of N from slow soluble samples.
Yield of dry matter of individual vegetables well correlated with uptake of nitrogen determined by balance and isotope methods.
Among both isotope technique introduced about twice lower utilization than balance method probably caused by priming effect of N and by unsuitable conditions for plant growth at unfertilized zero treatment.

Workshop Towards and Ecologically Sound Fertilisation in Field Vegetable Production

P. Tlustos, D. Pavlikova, J. Balik, V. Vanek

Nitrogen, ¹⁵N, yield, uptake, radish, lettuce, carrot

https://doi.org/10.17660/ActaHortic.2002.571.14