ISHS Acta Horticulturae 548: International Symposium on Growing Media and Hydroponics
EFFECTS OF SUBSTRATE LIMING AND FERTILIZER SUPPLY ON CABBAGE SEEDLINGS GROWN ORGANICALLY IN PLUGS |
| Author: | J. Willumsen |
| Keywords: | Brassica oleracea, propagation, recirculation, manure |
| DOI: | 10.17660/ActaHortic.2001.548.38 |
| Abstract:
Experiments with organically grown seedlings of white cabbage (Brassica oleracea L. var. capitata) were carried out to investigate the possibilities for improved nutrition during germination and subsequent growth in plug trays under glasshouse conditions. The plug substrates that were compared consisted of peat mixed with various quantities of poultry manure and dolomitic or ground limestone. Maximum growth was achieved in a substrate mix with 10 litres of composted poultry manure and 4-8 kg dolomitic limestone per m3 peat. Higher quantities of manure and a lower quantity of dolomitic limestone reduced plant growth. A dilute solution of liquid cattle manure was used as supplementary source of nitrogen (7 mmol l-1) and potassium (3 mmol l-1) and applied as a recirculated or non-recirculated nutrient solution on ebb/flood benches. Although pH of the liquid manure solution remained high (7-8) all through the experimental period, this did not create any problems for the plants as pH always remained between 5 and 7 in the peat mix of the plugs due to the buffer capacity of the peat mix and a high ratio between ammonium and nitrate in the solution. The experiments showed that organic production of cabbage seedlings in small propagation units may suffer from lack of available nutrients during the propagation period. Supplementary additions of fertilizer is suggested in order to meet the nutritional requirements rather than additions of a high quantity of an organic fertilizer to the propagation substrate prior to sowing. | |
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