Vegetative growth of rose flower in cocopeat and soil in Naivasha, Kenya
Ketter, N.C. ; Kariuki, W. ; Wesonga, J.M. ; Elings, A. ; Hoogerwerf, F. - \ 2015
Acta Horticulturae 1104 (2015). - ISSN 0567-7572 - p. 95 - 102.
Hydroponics - Leaf chlorophyll - Leaf growth - Rosahybrida - Water re-use
Roses in Kenya are mostly grown in soil with an open drip irrigation system which is inefficient as water and nutrients are lost through drainage. A study was carried out from January to December 2013 at a commercial rose farm in Naivasha, Kenya, to evaluate the potential of a cocopeat-based system, which additionally enables re-use of the drain water in a soil-based system. Vegetative growth in both systems was assessed in terms of leaf expansion, number of leaves, stem length, chlorophyll content (represented by the measured SPAD value) and flower head expansion. The water used throughout the year was also measured. Leaf expansion was characterized by an initial slow expansion rate followed by a fast expansion rate before levelling off. Maximum leaf length reached was 63 mm in the cocopeat system, while it was 60 mm in soil system; however, the difference was not significant. The number of leaves did not differ between the soil and cocopeat system. The maximum number of leaves per stem was 20 for both systems. There was no significant difference in stem length of plants in cocopeat system (650 mm) and in soil system (630 mm). Measured SPAD value on plants grown in the cocopeat system were significantly higher than for plants grown in soil (P0.01). Net water use for the cocopeat system was lower than for the soil system, with a difference of 1197 L m-2 or 58%, due to the re-use of water in a soil system. There was a significant substrate effect on the number of stems m-2 and measured SPAD value, which are associated with differences in leaf chlorophyll and nitrogen content. It is likely that the optimized fertigation regime in cocopeat system led to higher growth rates and enabled a higher stem production. Other parameters were not significantly affected by the substrate type under the same greenhouse climatic conditions.