Evaluation of rooting and growth of pitaya (Hylocereus spp.) cuttings in soilless production: comparison of hydroponic vs. aquaponic systems

Cogent Food & Agriculture ISSN: (Print) (Online) Journal homepage: www.tandfonline.com/journals/oafa20 Evaluation of rooting and growth of pitaya (Hylocereus spp.) cuttings in soilless production: comparison of hydroponic vs. aquaponic systems Gina Patricia Suárez-Cáceres, Miguel Malia-Torrejón, Luis Pérez-Urrestarazu, Jackson A. Gross & Víctor M. Fernández-Cabanás To cite this article: Gina Patricia Suárez-Cáceres, Miguel Malia-Torrejón, Luis Pérez- Urrestarazu, Jackson A. Gross & Víctor M. Fernández-Cabanás (2024) Evaluation of rooting and growth of pitaya (Hylocereus spp.) cuttings in soilless production: comparison of hydroponic vs. aquaponic systems, Cogent Food & Agriculture, 10:1, 2355298, DOI: 10.1080/23311932.2024.2355298 To link to this article: https://doi.org/10.1080/23311932.2024.2355298 © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group Published online: 31 May 2024. Submit your article to this journal Article views: 714 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=oafa20 Soil & Crop SCienCeS | reSearCh artiCle Cogent Food & AgriCulture 2024, Vol. 10, no. 1, 2355298 Evaluation of rooting and growth of pitaya (Hylocereus spp.) cuttings in soilless production: comparison of hydroponic vs. aquaponic systems Gina patricia Suárez-Cáceresa , Miguel Malia-torrejónb, luis pérez-Urrestarazua , Jackson a. Grossc and Víctor M. Fernández-Cabanásb aurban greening and Biosystems engineering research group. Area of Agro-Forestry engineering, universidad de Sevilla. etSiA, Seville, Spain; burban greening and Biosystems engineering research group, departamento de Agronomía, universidad de Sevilla, etSiA, Seville, Spain; cdepartment of Animal Sciences, university of California, davis, davis, California, uSA ABSTRACT effluents generated in aquaculture could contribute to increased risk of environmental contamination. aquaponic could facilitate the resolution of this problem by transforming those potential pollutants into nutrients for plants, providing an extra vegetable production in a circular economy framework. highly profitable vegetables such as pitaya (Hylocereus spp.) could improve the economic viability of these farms, but little is known about its performance in aquaponic systems. rooting and vegetative growth of 12 cuttings of white-fleshed pitaya (Hylocereus undatus) and red-fleshed pitaya (Hylocereus hybridum) were evaluated over a period of six months in two aquaponic systems rearing tilapia with different hydroponic subsystems (nutrient Film technique, nFt and Media Bed, MB). a control group of hydroponic culture using substrate filled pots was used for comparison. Water quality and environmental parameters were also measured to evaluate their influence on plant development. Hylocereus hybridum showed higher vegetative growth, and earlier shoot emission in combination with the control system, followed by the nFt and finally the MB. in relation to root growth, Hylocereus undatus showed best results in combination with the substrate system. Best results for precocity in root emission, evaluated in the nFt system, were obtained for Hylocereus hybridum. Water quality parameters had no significant effect on plant development, while fish live weight increased in both systems. 1. Introduction the world’s growing population demands more and more resources in the form of infrastructure and food, both of which require physical space in which to expand and grow, making it impossible to overlap using either of the traditional agricultural methods. this problem is compounded by the threat posed by the lack of irrigable land available to grow the necessary food using traditional agricultural methods (Mohapatra etal., 2020). For years, the human population continues to concentrate around urban centers, directly increasing the demand for food from rural communities. Furthermore, there exists a growing concern for food quality, traceability, safety, and environmental sustainability of farming methods. efforts are being directed towards new forms of local and sustainable food production systems under new and complementary production alternatives which are driven by crops destined for domestic use or self-consumption in backyards, rooftops, community gardens and urban farming (Maćkiewicz et al., 2019; nasr et al., 2017). With these changing demographic it is imperative to develop agri-food systems that can climate proof global food security without causing damage to biodiversity and ecosystem services. the 2030 agenda of the Un Sustainable Development Goals emphasizes the need to address these global challenges, by prioritizing the use of more efficient, productive and sustainable agrifood production models (Fao, 2019; Goddek et al., 2019). recognizing the increasing scarcity of resources on the planet, it is necessary to evaluate and support sustainable agriculture to supply earth’s 8 billion and rising human population (Greenfeld et al., 2021). © 2024 the Author(s). Published by informa uK limited, trading as taylor & Francis group CONTACT Víctor M. Fernández-Cabanás victor[email protected] urban greening and Biosystems engineering research group, departamento de Agronomía, universidad de Sevilla, etSiA, Ctra. utrera km. 1, 41013 Seville, Spain https://doi.org/10.1080/23311932.2024.2355298 this is an open Access article distributed under the terms of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. the terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent. ARTICLE HISTORY received 8 november 2023 revised 9 May 2024 accepted 10 May 2024 SUBJECTS agriculture & environmental Sciences; Marine & aquatic Science; plant & animal ecology KEYWORDS pitaya; aquaponic; hydroponic; circular economy; nFt; MB REVIEWING EDITOR Manuel tejada, Universidad de Sevilla, Spain 2 G. p. SUÁreZ-CÁCereS etal. in this context, aquaponics arises from the combination of two food production systems: hydroponics, consisting of the production of plants in soilless culture media, in synergy with recirculating aquaculture systems which focus on the production of aquatic animals. aquaponics is identified as a sustainable agricultural approach that increases water efficiency (it uses less than 90% of water compared to conventional production for a variety of vegetable species), reuses waste streams from fish culture by biotransforming nutrients into fertilizer and does not increase the pressure of urbanization on irrigable land (abusin & Mandikiana, 2020). these benefits further reinforce why aquaponic production systems are presented as a viable alternative for food production systems based on a circular economy. in general, aquaponic food production systems are governed by the principles of reduce, reuse and recycle, as opposed to conventional food systems based on a linear economy, governed by extraction, manufacture, use, and disposal (pérez-Urrestarazu etal., 2019). therefore, alternative production techniques such as aquaponics, which aim to reduce inputs and minimize pollution associated with food production systems (e.g., aquaculture effluents), are welcome (Blidariu & Grozea, 2011). the overall objectives of these alternative food production systems are to maximize resource efficiency and long-term production stability, resulting in increased producer incomes (tyson etal., 2011), while contributing to food security (Fernández-Cabanás et al., 2023). in countries of the Mediterranean region, which are more susceptible to the increasing prevalence of climate stressors, controlled environmental agriculture creates new opportunities for the introduction of new crops coming from warmer and less humid areas, such as dragon fruit (Hylocereus spp.). Currently, the production of certain economically valuable tropical crops is being promoted instead of importation due to the high demand in european markets of tropical species, such as avocados (Persea americana), mangoes (Mangifera indica) and pitaya (Hylocereus spp.). pitaya production in controlled environmental agriculture for medium and small farms has great potential, not only because of its adaptation to Mediterranean conditions (temperature and rainfall), but also because of its high profitability (trivellini et al., 2020). in order to promote crop health during vegetative propagation and even for pitaya production, some farms have implemented soilless cultivation (Mizrahi, 2015). Furthermore, in Spain, there is a company that has developed a multi-band gutter system for hydroponic production, formed by interconnected layers which create a multi-level circuit with the objective of generating small cascades that oxygenate both the nutrient solutions and the plants (nGS other Crops, 2024). this type of soilless production could be associated with recirculating aquaculture systems, incorporating the already mentioned environmental advantages of a circular economy to the production of highly profitable aquaponic crops. however, references in the scientific literature on vegetative multiplication and hydroponic production of pitaya are very scarce, and none exist for aquaponic production, which makes it difficult to assess its technical and economic feasibility. the main objective of this work was to evaluate the speed of rooting and vegetative growth in the first weeks of white-fleshed (Hylocereus undatus) and red-fleshed red pitaya (Hylocereus hibridum) cuttings in two aquaponic systems (nutrient Film technique, nFt and Media-Bed, MB), compared to a substrate culture system used as control. 2. Materials and methods 2.1. Location of the study and systems description this study was carried out in one of the greenhouses (65 m2 total area) at the School of agricultural engineering (etSia) of the University of Seville. two small-scale aquaponic systems, built under the guidelines of the handbook developed by Fao (Somerville et al., 2014), were compared with a control system consisting of pots with growth media and slow-release fertilizer. each of the aquaponic systems consisted of a fish production tank and two different hydroponic subsystems: nutrient Film technique (nFt) and media bed (MB). Figure 1 shows a schematic of the design of both systems including indications for the water flow. the nFt system included three tanks, a squared iBC (intermediate Bulk Container) of 1000 l capacity, which housed the fish; and two other 200 l cylindrical tanks which acted as mechanical and biological filters, respectively. the biofilter tank was filled with 1000 standard and 600 handmade 3 cm diameter bioballs, small, pegged plastic balls used as the biological media. these handmade bioballs were manufactured from small pieces of corrugated pVC pipes 0.03 m in diameter, one inserted into the other. this system consisted of five lines of pVC pipes of 90 mm diameter and 3 m length, which had 5 cm diameter holes cut every 25 cm, where the plant material was installed. CoGent FooD & aGriCUltUre 3 the MB system consisted of 6 tanks, one squared iBC of 1000 l capacity, which acted as fish tank; 4 iBC sections with 200 l, 3 of which contained the pre-washed lightweight expanded clay aggregate (leCa) for hydroponic production and biofiltration, and the last one operated as a sump tank; finally, 1 cylindrical tank of 200 l was used as a mechanical filter, improving the original design proposed by Fao (pérez-Urrestarazu etal., 2019). the choice of selected hydroponic subsystems is due to several reasons, among which it is worth highlighting that they are easy to operate and manage. Furthermore, they have been in operation for several years, and they are suitable for small-scale use, as is the case in this study, while not consuming large areas in the greenhouse. For the control system, 4 polyethylene trays were installed, each containing 6 pots (0.15 x 0.12 × 0.19 m3), resulting in a total of 24 pots. the substrate used was classified as specific for grafting: 50% fine blond peat, 50% black peat (projar professional Seed pro 5050). the pots were fertilized with slow-release osmocote (8.5 g/pot) to provide nutritional support for the plants in this system. Composition of osmocote was 15.0% n, 9.0% p, 12.0% K, 1.3% Mg, 5.9% S, 0.02% B, 0.05% Cu, 0.46% Fe, 0.06% Mn, 0.02% Mo, and 0.05% Zn. to record the environmental variables in the greenhouse, a hoBo data logger was placed in a central area of the greenhouse to record hourly temperature and relative humidity measurements during the 6 months of the study. 2.2. Fish production in aquaponic systems the fish studied was nile tilapia (Oreochromis niloticus), from fingerlings hatched at the same facility. the animals were kept in the aquaponic system for six months, during which time the water conditions were optimal for the fish, with an average water temperature of 23.8 °C, a ph close to neutral and an average nitrate concentration of 112 mg/l. in order to recreate similar biotic conditions for both aquaponic systems, fish biomass introduced in each tank was equivalent. the nFt system contained a biomass of 18.24 kg of tilapia, while the MB system supported a biomass of 18.36 kg. each system contained a total of 20 individuals. once set up, daily operations with the fish consisted of feeding them with the feed ration, calculated as 1% of the live weight of the animals, with half in the morning and half in the afternoon. a total of 180 g of feed per tank and day was provided, containing 32% protein and 6% fat. one fish died during the study in MB system. at the end of the trial, the fish from each system were weighed to compute total growth. the trial was approved on 1 December 2021 by the Comisión de ordenación académica of the escuela técnica Superior de ingeniería agronómica of the University of Seville (approval code: 44052787/2021). the study followed the arriVe guidelines. the fish, housed in the research and teaching Farm of the higher technical School of agricultural engineering of the University of Seville (code eS410910000211 in the official registry of livestock Farms), were handled in conditions similar to those of the commercial aquaculture farms. 2.3. Plants production in three systems the plants belonged to two cultivars of pitaya (Hylocereus spp), the red cultivar with white flesh (Hylocereus undatus) and the red cultivar with red flesh (Hylocereus hybridum). this plant material was kindly provided by Dr. García García (iFapa "la Mojonera" center in almería, Spain). the plant material was received in the form of stems or cladodes, a total of 27 units, each about Figure 1. Schematic of the design and components of aquaponics systems. Arrows indicate water flow. 4 G. p. SUÁreZ-CÁCereS etal. 60–70 cm long, of which 13 belonged to the red-fleshed and 14 to the white-fleshed cultivar. three to four cuttings were obtained per cladode, each about 15 cm long (Montesinos et al., 2015). Before cutting, each cladode and the instruments used were disinfected in a 10% aqueous solution of sodium hypochlorite. a total of 72 cuttings were obtained, 36 for each cultivar, which were placed on absorbent paper in a cool, dark place for a total of 4 days, after which they were transplanted into the hydroponic subsystems (12 cuttings of each cultivar in each of the studied systems). no special permits were required to work with the plants as they are all commonly grown in the study area and the trials were carried out in properly isolated hydroponic systems in an experimental greenhouse. 2.4. Experimental methodology this trial was carried out for 6 months (May to november 2021). Cuttings belonging to the white-fleshed red cultivar (Hylocereus undatus) were identified with the letter "B" followed by the corresponding cutting number (from 1 to 36). Cuttings belonging to the red-fleshed red cultivar (Hylocereus hybridum) were identified with the letter "r" and the corresponding cutting number (from 1 to 36) (Figure 2). the cuttings of both varieties were randomly distributed in each of the three systems (nFt, MB and control), a total of 12 cuttings of each cultivar in each system, that is, 24 plants per system. Due to the youth of the plant material, its low photosynthetic capacity and the high input of nutrients from the aquaculture systems, it was necessary to previously install a complementary plant community to consume this excess of nutrients in both aquaponic systems. in the nFt system, a selection of horticultural species were included (Figure 2a): basil (Ocimum basilicum), strawberry (Fragaria × ananassa), pepper (Capsicum annuum), cucumber (Cucurbita pepo) and carnation (Dianthus caryophyllus). in the MB system, the tank closest to the fish tank also supported a variety of crops (Figure 2B): pepper (Capsicum annuum), chicory (Cichorium endivia), Figure 2. distribution of plants in the three studied systems. A) nFt system. B) MB system. C) Control system. Pi: Capsicum annuum; Esc: Cichorium endivia; Cb: Cucurbita pepo; Alb: Ocimum basilicum; Fr: Fragaria × ananassa; Clv: Dianthus caryophyllus; Lir: Lilium candidum. R1-R36: Pitaya red-fleshed cultivar (Hylocereus hybridum); B1-B36: Pitaya white-fleshed cultivar (Hylocereus undatus). CoGent FooD & aGriCUltUre 5 cucumber (Cucurbita pepo), carnation (Dianthus caryophyllus) and lily (Lilium candidum). Finally, the control system with universal substrate was placed in 4 polyethylene trays (Figure 2C). the care and recording of the growth of the shoots and roots of the pitaya cuttings was carried out by means of a weekly schedule. at the beginning of the trial, operations with the plants were limited to checking the existence of any shoot or root emission. these operations were carried out in the nFt system, where the cuttings could be extracted without damaging the roots. this system was maintained for 4 weeks, until most of the cuttings in the nFt system were rooted, at which time, in early June, a complete root measurement was taken for the 3 systems, taking into account the average diameter of the roots of each cutting and, if present, the length of the longest root. regarding the growth of the shoots, a weekly record was made by measuring each of the cuttings of each system with a tape measure, noting down any relevant observations. photographs were taken at the first stages of vegetative growth for each of the systems and varieties. 2.5. Operations carried out on the water in the aquaponic systems Weekly, the water temperature in the fish tank was taken, as well as water quality parameters such as ph with a "hanna" ph meter, electrical conductivity (eC) and salinity (naCl) with a “Crimson" conductivity meter, and nitrate content with a photometrically operated electronic apparatus (reflectoquant from Merk®) and test strips. Depending on the results of the water analyses collected every week, potassium hydroxide and/or potassium carbonate were applied depending on the ph of each system, which should not fall below 6. in addition, iron in the form of eDDha was applied to the water every 2 weeks to prevent possible iron deficiencies in the plant material inherent in aquaponic systems (Fernández-Cabanás et al., 2020). 2.6. Statistical analysis the collected data were analysed with Statgraphics Centurion XViii (Statistical Graphics Corp., rockville, MD, USa, 2002). a variance check was performed using the Shapiro-Wilk (normality) and levene (homoscedasticity) test. Where necessary, the data were transformed, and in cases where the anoVa hypotheses of equality of variance were not met, non-parametric methods (Kruskall-Wallis) were used. additionally, lSD test were performed. a General linear Model (GlM) has been carried out in which the effect of the factors "hydroponic System", "Cultivars" and the interaction of both factors on the vegetative growth of the plants has been considered as the dependent variable. GlM was also used to evaluate the precocity of appearance of shoots and roots, considering the effect of the factors "hydroponic System", "Cultivar" and the interaction between both factors, applying the same tests of separation of means. 3. Results During the study, temperatures inside the greenhouse ranged from 9.06 to 47.29 °C, with average daily values around 27 °C, while relative humidity varied from 7.43 to 95.39%, with average daily values around 54%, as it can be appreciated in Figure 3. in relation to water quality parameters, nitrate values varied between 18 and 201 mg l−1 (Figure 4a). eC was maintained below 1 dS/m, with oscillations due to water change (Figure 4B). the ph values obtained in this test ranged from 4.3 to 9 in both systems (Figure 4C). Due to the observed decreasing ph trend, an attempt was made to maintain neutral ph values by renewing the water when the analyses results were extreme and by adding Koh and KhCo3 at the doses of 20 and 40 g, respectively. average water temperature ranged between 18.25 and 26.9 °C during the study period (Figure 4D). Water quality resulted appropriate for tilapia growth, as can be inferred from fish biomass increase throughout the test period in both systems showed in table 1. among all the factors taken into account in this project, three systems (nFt, MB and control) and two varieties (red-fleshed and white-fleshed), one of them, the MB system, failed to complete the trial because of a generalized root and stem soft rot that appeared in the greenhouse 155 days after the start of the trial. it was found that all the plants showing this symptomatology belonged to the red-fleshed cultivar and, after laboratory analysis, it was presumed that the cause could be Fusarium, so the affected plant material was immediately removed. in addition, throughout the 6 months of the experiment, there were reported several attacks by rodents and ants on the plant material, as stems are a kind of fleshy material susceptible to attack. to avoid this, 6 G. p. SUÁreZ-CÁCereS etal. rodent traps were placed throughout the greenhouse, as well as insecticides for ants. Figure 5 shows the vegetative growth in centimeters for each cultivar during the 184 days of the trial for each of the studied systems. the results obtained from the anoVa and GlM analyses are presented below. in a first analysis, the independent variables analyzed were System (3 factors) and Cultivar (2 factors), and the dependent variable was the vegetative growth during the first 155 days of the trial, before the appearance of stem and root rot in the MB system. results are displayed in tables 2 and 3. as interaction of system and cultivar (SxC) resulted significant (p > 0.001), both factors should be considered simultaneously in the statistical analysis. thus, a GlM analysis was performed including both factors (table 4). the system that showed best results for any of the cultivars was control in pots with substrate, resulting in a lower vegetative growth rate for aquaponic systems. Moreover, the daily growth rates increased as the cultivation time was higher. these results indicate that each cultivation system as well as the selected cultivar will evolve differently depending on the combination of both factors. in the case of the precocity in the emission of shoots, it was measured as the number of days elapsed until the appearance of the first sprout. table 3 shows that both considered factors resulted significant, but not their interaction. table 5 illustrates results for GlM analysis for factors system and cultivar, concluding that the red pitaya with red pulp shows a much higher precocity than the one with white pulp. if we refer to the factor "System", the one with the highest earliness is the substrate, followed by the nFt and, lastly, the MB system. table 6 shows the results of the analysis of variance for the different factors that can condition the measurements related to root growth. the System Figure 3. evolution of A) ambient temperature (° C) and B) relative humidity (%) in the greenhouse throughout the study. CoGent FooD & aGriCUltUre 7 (3factors) and Variety (2 factors) have been analyzed as independent variables, and the root growth measurement (in cm) 28 days after the start of cultivation as dependent variables. interaction of both factors and System resulted significant. i.e., that the root growth will depend on the cultivar and on the system. as regards root growth (table 7), both varieties of pitaya showed statistically similar results in the MB and nFt systems, but not in the case of the control system. in the latter case, it is the red cultivar with white pulp that shows the best results in terms of root growth. these results confirm that the cultivation system in which the pitaya is grown will influence its development. regarding the earliness in root emission, in order not to damage the roots during the evaluation process, measurements were made only in the nFt system, where the plant can be manipulated to observe the roots without problems. the GlM analysis performed for precocity for root emission, determined as the number of days until the issuance of the first roots, indicated significant difference (p-value < 0.05) between the white-fleshed (21.58 + 2.234 days) and the red-fleshed (12.17 + 1.127 days) cultivars. a higher earliness for roots emission was observed for the red-fleshed cultivar. 4. Discussion the parameters related to environmental temperature and relative humidity are within the values recommended by other authors for similar situations. in this sense, lezama etal. (lezama etal., 2009) pointed out average environmental temperatures ranging between 18 and 25 °C for this crop, while Junta de andalucía (19) informed that, in some cases, extreme Figure 4. A) evolution of nitrate no3- (mg/l). B) evolution of the electrical Conductivity (dS/m) of water in aquaponic systems. C) evolution of the pH of water in aquaponic systems. d) evolution of the average temperature (°C) of the water in aquaponic systems. MB: Media Bed. nFt: nutrient Film technique. Table 1. evolution of average fish weights throughout the trial, measured at the beginning (May 4, 2021) and at the end of the project (november 10, 2021). System dates n° days n° fish lW total (kg) Weight gain (kg) nFt Start 190 20 18.24 6.8 end 20 25.04 Media-Bed (MB) Start 190 20 18.36 6.54 end 19 24.9 8 G. p. SUÁreZ-CÁCereS etal. values of 40 °C and 5 °C could be reached without causing any damage to the plant. Salinas (Salinas, 2021) reported that pitaya is a crop that requires a high environmental humidity to be able to develop its vegetative cycle properly, between 60 and 80%. likewise, Castillo etal. (Castillo et al., 1996) mentioned that, under natural growing Figure 5. evolution of vegetative growth (cm) of pitaya in MB, nFt and control systems. A) White-fleshed cultivar (Hylocereus undatus). B) red-fleshed cultivar (Hylocereus hybridum). Table 2. Analysis of variance (AnoVA) of vegetative growth of pitaya for each cropping system and cultivar studied during the first 155 days. Factor degree of freedom Mean square F-value System (S) 2 231296 97.11*** Cultivar (C) 1 299615 125.80*** SxC 2 56089.8 23.55*** Error 1866 2381.73 Where: n.s.: Statistically not significant, p > 0.05; *p < 0.05; **p < 0.01; ***p < 0.001. Table 3. Analysis of variance (AnoVA) for the earliness of pitaya shoot emission for each cropping system and cultivar studied. Factor degree of freedom Mean square F-value System (S) 2 2619.35 13.07*** Cultivar (V) 1 10682.3 53.31*** SxV 2 353.014 1.76 n.s. Error 66 200.383 Where: n.s.: Statistically not significant, p > 0.05; *p < 0.05; **p < 0.01; ***p < 0.001. Table 4. general linear Model (glM) for the evolution of vegetative growth of pitaya, in centimeters, for each cropping system and cultivar studied during first 155 days. Cultivar (C)\System (S) White-fleshed cultivar red-fleshed cultivar Media-Bed (MB) 37.14 ± 2.17 a 42.43 ± 2.437 a NFT 36.94 ± 3.03 b 79.94 ± 3.230 a Control 64.48 ± 3.142 b 92.03 ± 3.275 a Where: different letters (a, b) indicate significant differences in the same row.