caa a22 4500 477112307 CHVBK 20180405111612.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF02185566 doi (NATIONALLICENCE)springer-10.1007/BF02185566 Gaseous nitrogen losses from a soilless culture system in the greenhouse [Elektronische Daten] [Diemo Daum, Manfred Schenk] Gaseous nitrogen losses from a closed-loop rockwool system were investigated during the vegetative growth and the stem fruit stage of cucumbers. On average 12.4% of the N input were released in form of N2O and N2. This was equivalent to a mean emission rate of 0.62 kg nitrogen per hectare greenhouse area and day. The highest emission rates occurred during the stem fruit development as an increased root decay and an intensive substrate respiration came on. The proportion of N2O in the gaseous nitrogen losses decreased with increasing N2O+N2 evolution. On average it amounted to 9.6%. A comparison of different cucumber crops during the season showed that the gaseous nitrogen losses were nearly twice as high in the summer as in the autumn. Thus it proceeded almost parallel to the plant growth which also doubled. Furthermore, an effect of the substrate temperature is conceivable, since it was 3-4°C higher in the radiation-rich summer-time. With increasing root density in the substrate gaseous nitrogen losses increased while the N2O/N2 ratio declined. Possible reasons for this were a greater rhizodeposition of easily decomposable organic substances, an accelerated oxygen consumption by root respiration and a high density of microorganisms in close vicinity to the roots. The growth of green algae on the substrate surface stimulated the production of N2O. Kluwer Academic Publishers, 1996 cucumber nationallicence denitrification nationallicence nitrous oxide nationallicence soilless culture nationallicence Daum Diemo Institute of Plant Nutrition, University of Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany aut Schenk Manfred Institute of Plant Nutrition, University of Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany aut Plant and Soil Springer Netherlands; gopher://gopher.wkap.nl 183/1(1996-06-01), 69-78 0032-079X 183:1<69 1996 183 11104 https://doi.org/10.1007/BF02185566 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02185566 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Daum Diemo Institute of Plant Nutrition, University of Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany aut NATIONALLICENCE 700 1- Schenk Manfred Institute of Plant Nutrition, University of Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany aut NATIONALLICENCE 773 0- Plant and Soil Springer Netherlands; gopher://gopher.wkap.nl/ 183/1(1996-06-01), 69-78 0032-079X 183:1<69 1996 183 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer