Effect of Growing Media on Yield and Quality of Soilless Cultivated Rose

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1 Effect of Growing Media on Yield and Quality of Soilless Cultivated Rose G. Fascella and G.V. Zizzo C.R.A. - Istituto Sperimentale per la Floricoltura, Sezione di Palermo S.S. 113, Km Bagheria (Palermo) Italy Keywords: Rosa hybrida, growing techniques, substrates, varieties, bag culture Abstract A two-year trial of open-cycle soilless cultivation of four varieties of rose was conducted in Bagheria (Sicily, Italy), in an unheated greenhouse with metal structure and polyethylene cover, with the aim of evaluating the influence of two growing media on quantitative and qualitative parameters of cut flower production. Plants of the cv. Anastasia, Fenice, New Fashion and Gold Strike were grown in plastic bags filled with perlite, pure or mixed with coconut coir dust (1:1, v/v). Growing media affected yield and quality: perlite/coir dust caused the highest amount of flowers (17.7 stems/plant) and the longest stems (65 cm). Significant differences were also recorded among varieties: cv. Anastasia produced the highest number of stems (18.7 per plant) and the longest buds (5.8 cm); cv. Fenice provided flowers with the maximum average length (7 cm); cv. New Fashion gave the highest amount of leaves/stem (55.8). Substrates also differed in water consumption (.78 and.62 L/plant/day for plants in perlite and in perlite/coir, respectively) and available mineral elements, with a lower availability of nutrients for the plants grown in the inert media. The best results in the mixture are probably related to the higher water holding capacity and cation exchange capacity of coconut dust, proving this organic material as one of the main alternatives to peat for hydroponic culture. INTRODUCTION The spreading of hydroponics in southern Europe regions is rather new and it has been restricted by the high costs and the difficulty of management of this new technology. The development of soilless culture for cut flower production in Mediterranean areas as south Italy is strongly linked to the accurate choice of growing media from technical, economical and ecological reasons. In the open systems this selection becomes critical: some inert substrates show low water holding capacity with high spreading out (drainage) of nutrient solution; some organic materials have high water retention but are easily degradable and then low-lasting; others present high prices, limited availability or problems of removal. Alternative solutions are continuously tested (Pisanu et al., 1994; Domingues and Minami, 24; Frangi et al., 24) and proposed in order to increase crop response and to reduce both prime costs and environmental impact. Rose (Rosa hybrida) is one of the most widely cultivated flower species with the soilless technique and several investigations were conducted in mild-winter zones using inert (Maloupa et al., 1999; Paradiso et al., 23) and organic (Syros et al., 21) substrates or mixtures of both. But, on the contrary, reports on hydroponic cultivation of rose in Sicily are scarce and incomplete (Miceli and Moncada, 2). Taking these factors into account, and with the aim to collect more detailed information on soilless response of rose in the Sicilian environment, a trial with bag culture of four varieties was carried out in order to evaluate the influence of two growing media on yield and quality of cut flowers. Proc. IS on Soilless Cult. and Hydroponics Ed: M. Urrestarazu Gavilán Acta Hort. 697 ISHS

2 MATERIALS AND METHODS The trial was conducted in Bagheria (near Palermo, Sicily, 38 5 N, E, 23m above sea level), during the years 23/24, in an unheated east-west oriented greenhouse (34 x 16 m) with zinc-coated structure and polyethylene cover (Ø.15 mm). Plants of the cv. Anastasia, Fenice, New Fashion and Gold Strike grafted on Rosa indica major were grown following the arching technique in white plastic bags (1 x 5 cm) filled with perlite, pure or mixed with coconut coir dust (1:1, v/v), in an open system. The main physical properties and the chemical characteristics of the used substrates, determined according to De Boodt et al. (1974) and to Sonneveld et al. (1974) respectively, are reported in table 1. Each bag supported 1 plants with a final density of 4.5 plants/m 2 of cultivated soil. Planting was accomplished in January 23. Bags were placed on polystyrene blocks in order to raise them from the ground. A split-plot experimental design (2 substrates x 4 cultivars) with 4 replicates per treatment was used; each replication consisted of 2 plants (experimental unit). Water, macro and microelements were supplied through a drip fertigation system (1 dripper/plant) controlled by a timer. Plants were fed with a nutrient solution with the following composition (mg/l): 18 N total, 5 P, 2 K, 11 Ca, 3 Mg, 1.4 Fe (EDTA),.2 Cu,.2 Zn,.3 Mn,.2 B,.3 Mo. The ph and the electrical conductivity were maintained at 5.8 and 1.8 ms/cm, respectively. Solution supply varied from.8 to 1.6 L/plant/day (corresponding to 4 and 8 irrigations/day), and from.6 to 1.2 L/plant/day (3 and 6 irrigations/day) for perlite and perlite/coir, respectively. Daily irrigation timing was based on the integrated solar radiation plan: deliveries started when measurements reached, for each material, predetermined thresholds. The duration of each irrigation was adjusted when the leachate fraction exceeded the range of 1 25 %. This fraction was calculated by collecting the drainage solutions. Water consumption was estimated as the difference between the solution applied and the corresponding percolated volume. The amount of nutrients available for plants was determined, for each substrate, as the difference between the given solution and the collected leachate mineral contents. Data for air temperature and relative humidity inside the greenhouse were collected throughout the experiment. Productive (flowering period, yield trend, number of stems/plant, number of petals/bud and number of leaves/stem) and biometrical parameters (stem length and thickness, bud height and diameter) were recorded. Data, referred to a 17 months-period (Apr 3 - Sep 4), were analyzed according to ANOVA and means were separated by Duncan s multiple range test. RESULTS Mean monthly air temperatures ranged from a minimum of 11 C to a maximum of 29 C, and relative humidity values varied from 46 % to 77 % (Fig. 1). These environmental greenhouse conditions and the cultivation protocol applied allowed a fast development of the plants, thus avoiding hydro-thermal stresses and injuries to the flower stems. Flower production started 1 days after planting, with no differences between substrates but only among varieties (cv. New Fashion bloomed 11 days later than the others; data not shown). Substrates affected yield and quality: plants grown in the organic mixture gave higher amount of flowers than those in inert media (17.7 and 13.6 stems/plant, respectively), as well as longer stems (65 versus 58 cm) (Table 2). No differences were observed for the other studied parameters. Plants cultivated on both growing media displayed the same yield pattern, with a total (cumulative) production of 97 and 132 stems, for perlite and perlite/coir, respectively, during 23, and of 176 and 223 stems during 24 (Fig. 2). The harvest of stems stopped only twice during the summer (Sept 3) and the winter (Mar 4) pruning. The tested varieties differed in quantitative and qualitative parameters of rose production: cv. Anastasia gave the highest number of stems (18.7 per plant) and the longest 134

3 buds (5.8 cm) (Table 2); cv. Fenice provided flowers with the maximum average length (7 cm); and cv. New Fashion produced the highest amount of leaves/stem (55.8). With regard to the water consumption, average volumes of.78 and.62 L/plant/day were recorded for plants in perlite and in mixture, respectively, with differences between substrates of.18 and.11 L/plant/day (perlite versus perlite/coir) during the summer and the winter periods (Fig. 3). Growing media also differed in mineral elements availability for plants, actually the organic mix showed a higher amount of nutrients, particularly cations (K, Ca and Mg), as well as NO 3 - and P (Table 3). DISCUSSION The results showed that, under the conditions of our experiment, in an open-cycle soilless cultivation of rose plants using perlite pure or mixed with coir dust, best yield and stem quality can be achieved with the second substrate. This response supports similar outcomes previously recorded with organic media (Blom, 1999; Allera et al., 2; Maloupa et al., 21). The good results obtained with the mixture are probably related to the physical and chemical characteristics of coir dust and, in particular, to its higher water holding capacity and cation exchange capacity. Coir properties were investigated by other authors (Brückner, 1997; Martinez et al., 1997; Noguera et al., 1997; Konduru et al., 1999). The balanced level of humidity in the organic mixture together with a sufficient degree of aeration, not too far from perlite s one, could establish better environmental conditions in the root zone which is also distinguished by a good availability of nutrients. It is known that coir dust may present some chemical and hydrological characteristics (organic matter content, C.E.C., water retention) similar to peat, but with a higher ph and durability (Prasad, 1997). These features confirm this substrate, with plant origin, as one of the main alternatives to peat and as an organic component of mixtures for hydroponic culture (Meerow, 1999; Pozzi et al., 23). That makes it highly suitable when combined with inert materials as perlite or pumice for open soilless systems in regions like Sicily, with limited water resources and a low technological level for floriculture. Literature Cited Allera, C., Castello, S. and Farina, E. 2. Crescita e produzione di rosa su fibra di cocco e su sabbie a diverse granulometrie. Colture Protette 9: Blom, T.J Coco coir versus granulated rockwool and arching versus traditional harvesting of roses in a recirculating system. Acta Hort. 481: Brückner, U Physical properties of different potting media and substrate mixtures - especially air- and water capacity. Acta Hort. 45: De Boodt, M.F., Verdonck, O.F. and Cappaert, I.M Method for measuring the water release curve of organic substrates. Acta Hort. 37: Domingues, S.E. and Minami, K. 24. Evaluation of different substrates on lisianthus (Eustoma grandiflorum Shinn) growth. Acta Hort. 644: Frangi P., D Angelo, G. and Castelnuovo, M. 24. Evaluation of water and nutritional consumption of New Guinea impatiens an poinsettia grown in two compost based substrates. Acta Hort. 644: Konduru, S., Evans, M.R., and Stamps, R.H Coconut husk and processing effects on chemical and physical properties of coconut coir dust. HortScience 34:88-9. Maloupa, E., Samartzidis, C., Couloumbis, P. and Komninou, A Yield, quality and photosynthetic activity of greenhouse-grown Madelon roses on perlite-zeolite substrate mixtures. Acta Hort. 481: Maloupa, E., Khelifi, S. and Zervaki, D. 21. Effect of growing media on the production and quality of two rose varieties. Acta Hort. 548: Martinez, F.X., Sepó, N. and Valero, J Physical and physicochemical properties of peat-coir mixes and the effects of clay-material addition. Acta Hort. 45: Meerow, A. W Growth of two subtropical ornamentals using coir (coconut mesocarp pith) as a peat substitute. HortScience 29:

4 Miceli, A. and Moncada, A. 2. Primi risultati della coltivazione della rosa fuori suolo in Sicilia. Atti Convegno sulle colture floricole fuori suolo: strategie per la riduzione dell impatto ambientale (Ercolano, 25 novembre): Noguera, P., Abad, M, Puchades, R., Noguera, V., Maquieira, A. and Martinez, J Physical and chemical properties of coir waste and their relation to plant growth. Acta Hort. 45: Paradiso, R., Raimondi, G. and De Pascale, S. 23. Growth and yield of rose in a closed system on two inert substrates. Acta Hort. 614: Pisanu, A.B., Carletti, M.G. and Leoni, S Gerbera jamesonii cultivation with different inert substrates. Acta Hort. 361: Pozzi, A., Frangi, P., Castelnuovo, M. and Pardossi, A. 23. Growth and flowering of geranium and New Guinea impatiens in peat-reduced and in peat-free substrates watered with different irrigation systems. Acta Hort. 614: Prasad, M Physical, chemical and biological properties of coir dust. Acta Hort. 45:21-3. Sonneveld, C., Van Den Ende, J. and Dijk, P.A Analysis of growing media by means of a 1:1,5 volume extract. Comm. In Soil Science and Plant Analysis 5: Syros, T., Economou, A., Galaftis, A., Tsicritsis, G. and Ralli, P. 21. A comparative study of rose cultivation on coco-soil and pumice with recirculation of the nutrient solution. Acta Hort. 548: Tables Table 1. Physical and chemical characteristics of the studied growing media. Perlite Perlite/Coir dust Bulk density (g/cm 3 ).8.15 Total pore space (% vol) Air capacity (% vol) Water holding capacity pf 1 (% vol) *ph (H2O) Cation exchange capacity (me/1 g) *measured on watery extract 1:1,5 (v/v) 136

5 Table 2. Influence of substrates and varieties on quantitative and qualitative parameters of rose flower stems. Stem/plant (No.) Stem length Stem thickness Bud length Bud diameter Petals/bud (No.) Leaves/stem (No.) Perlite 13.6 a 58.1 a.76 a 5.27 a 5.12 a 38.3 a 49.5 a Perlite/Coir dust 17.7 b 65. b.84 a 5.36 a 5.23 a 39.4 a 49.9 a ** ** ns ns ns ns ns Anastasia 18.7 a 61.3 b.9 a 5.8 a 5.35 a 44.7 a 49.8 b Fenice 14.5 b 7.1 a.87 a 5.3 b 5.1 ab 31. c 41.1 c New Fashion 12.9 b 5.8 c.75 b 5.1 c 5.3 a 42.2 ab 55.8 a Gold Strike 14.9 b 63.9 b.71 b 5.1 c 5. b 37.5 b 52.2 b ** ** ** ** ns * ** Interaction (sub x var) ns * ns * ns * * Within a column, means followed by different letters are significantly different at P<.1 (Duncan s multiple range test).ns=not significant,*=significant at P<.5,**=significant at P<.1 Table 3. Mean nutrient availability (mg/plant/day) for plants grown in the tested materials. Element Perlite Perlite/Coir dust - NO 3 - N NH 4 - N P K Ca Mg Fe Cu.1.2 Zn.1.2 Mn.1.2 B.1.1 Mo

6 Figures C temp R.H. Feb '3 Apr Oct Dec Feb '4 Apr Fig. 1. Mean monthly air temperature ( C) and relative humidity (%) recorded in the greenhouse during the trial % Total no. of stems/plant Perlite Perlite/Coir dust Apr '3 Oct Dec Feb '4 Apr Fig. 2. Average yield trend of the tested cultivars in the two substrates - Mean ± standard error. 1,8 Perlite Perlite/Coir dust L/plant/day,6,4,2 Summer Winter Fig. 3. Mean seasonable water consumption of rose plants in the two studied growing media - Mean ± standard error. 138