ISHS Acta Horticulturae 150: International Symposium on Substrates in Horticulture other than Soils In Situ
NITROGEN DYNAMICS IN BARK COMPOST AS DEPENDENT ON PRODUCTION METHODS - I. MODEL TRIALS |
| Authors: | R. Gutser, K. Teicher, P. Fischer |
| Abstract:
In model trials without plants (25° C, 90 % of water holding capacity), the change of soluble (0.025 N CaCl2) mineral N (NO3, NH4) in bark composts was studied for 17 weeks without and with N-application (80 mg N as NH4NO3/20 g compost dry matter). 8 bark composts, produced by different fermentation procedures, were compared with sphagnum peat: 4 long-term composts ± N-application for fermentation 3 short-term composts + N-application for fermentation 1 bark compost from a depot (about 25 years old) - N-application The amounts of Ct varied between 27 and 42 %, Nt between 0.66 and 1.16 % i.dry matter. Long-term fermented bark composts showed nearly a constant supply of soluble N during the first 10 weeks; lateron the amounts of Nmin decreased slowly similar to peat (N-fixation). The depot-bark strongly fixed fertilizer-NH4 (C/N = 47). Short-term composts were very variable in Nmin -contents (N-fixation and remineralization). The great differences in nitrification capacity of tested bark composts were independent of method of fermentation respectively pH of compost (pH 5.2–7.6); this may be mainly explained by different degrees of pollution with soil. | |
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