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Publication
Efficiency of organic nitrogen fertilization of potato in Northeast Portugal
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Advisor(s)
Abstract(s)
The study was conducted over a 4 year period with the purpose of measuring N mineralization using an in situ incubation technique, following the application of farmyard manure, poultry manure or municipal solid waste. The results varied from –10 % (net immobilization) to +28 % (net mineralization) in relation to the total organic N applied. N fluxes were assessed through plant N analysis during the growing season and through determination of potato tuber dry weight (TDW), N uptake by tubers and the apparent N recovery (ANR) of added N at harvest. Organic material applications slightly increased TDW above the control treatment (9 to 25%), although the results indicate a shortage of N, where no N was added to the crop. The effect of organic fertilization on N uptake by tubers was also limited. Petiole nitrate concentration and estimated net N mineralization were in agreement with trends in TDW and N uptake by tubers, with no differences in soil N availability between the control and organic treatments. Values of ANR were particularly low, ranging from 4 to 23 %. The results suggest that caution is needed when judging the contribution of organic fertilization to N nutrition of crops, which have a short growing season. Synchronization between N release and plant uptake is discussed.
Description
Keywords
Farmyard manure Municipal solid waste Poultry manure Nitrogen mineralization Nitrogen uptake Solanum tuberosum L.
Citation
International Conference on Environmental Problems Associated with Nitrogen Fertilisation of Field Grown Vegetable Crops. Potsdam, 2001. p. 179-186. ISBN 978-90-66059-74-0
Publisher
International Society for Horticultural Science