Nitrogen availability in composted cork

Title	Nitrogen availability in composted cork
Publication Type	Conference Paper
Year of Publication	1997
Authors	Carmona, E., Ordovas J., Ortega M. C., & Aguado M. T.
Editor	Roeber, R. U.
Conference Name	INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND PLANT NUTRITION IN HORTICULTURE
Date Published	1997///
Publisher	INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE
ISBN Number	90-6605-988-5
Keywords	bark; growing media; N immobilization
Abstract	Previous studies showed that plants grown in fresh cork (Quercus suberL. bark) had a reduced growth compared with peat and low rates of N. In composted cork, however, plant growth was similar with those in peat, but the N content of plants was still slightly lower. The purpose of this study was to investigate N availability in fresh and composted cork during 4, 5.5 and 7 months, using peat as control medium. The substrates were also incubated at 25 degrees C during 60 days after adding 0.25, 1.0, 1.75 or 3.0 g ammonium nitrate per 1 of substrate. Samples were taken periodically to measure NO3-N, NH4-N and total N. Also the Nitrogen Drawdown Index (NDI) for the addition of 75 mg.l(-1) N and 150 mg.l(-1) N was measured after incubation at 25 degrees C. N immobilization rates were well correlated to NDI. NH and soluble N drawed down rapidly in cork substrates while total N stayed constant. High rates of ammonium nitrate should be added to maintain a constant level of available N to plants in cork.