INTRODUCTION
The limited open land in urban areas impacts the urban farming methods, i.e., using soil versus planting media. Hydroponic planting is an alternative solution for urban farming as it requires no soil media. Hydroponics is widely practiced and has been developed into several methods as agricultural technology develops.
Some commonly applied hydroponic methods include water culture, wick system, drip system, ebb and flow system, nutrient film technique (NFT), and aeroponics.
In addition, hydroponic techniques provide economic benefits because it is not limited by external plant growth factors such as climate and season.
Kai-lan (Brassica oleracea var. alboglabra) is one of the most famous horticultural plants cultivated using a hydroponics system. It is an annual and short- lived vegetable crop with a great market demand because of its good taste and nutritional content. Kai-
lan is generally harvested in a short time to produce a product called baby kai-lan. This product has good prospects because of its high economic value.
Various nutritional contents such as vitamin A, vitamin C, thiamin, lime, and carotenoids are some reasons people consume kai-lan as a nutrient source and even as alternative medicine (Hirani & Li, 2021). Baby kai- lan has good economic value because it is favorable to middle to upper-class consumers, thus widely served in restaurants and hotels. The high economic value requires the cultivation to be carried out systematically and optimally to produce quality products.
Several plant growth factors must be controlled to ensure the success of the hydroponic cultivation process, namely water management, the use of nutrient solutions, the selection of planting media, and the quality of crop yields. The amounts of water and the nutritional intake of the plants should be appropriately regulated. The nutrition treatment must ARTICLE INFO
Keywords:
Nutrient film technique Nutrition solutions Planting media Product quality Article History:
Received: September 9, 2020 Accepted: September 7, 2022
*) Corresponding author:
E-mail: azmi.gabriel@uisi.ac.id
ABSTRACT
The production of Brassica oleracea var. alboglabra (commonly known as baby kai-lan) with nutrient film technique can generally be performed in a relatively short period to get a high selling value of products. This study aims to determine the effect of several types of nutrients and growing media applications on the productivity and quality of baby kai- lan products. The research involves two test variables (nutrition and planting media) with three variations of plant nutrition and four kinds of growing media. The physical and morphological analysis results provide information on leaf width parameters. Concerning medium, perlite shows the best average yield in each plant variation. Regarding nutrients, product “Z” nutrition has the most substantial influence on the growth of the object of research. The physical and morphological tests show that the average number of leaves in almost all treatments is seven. However, the highest average number of leaves is achieved by treatments using perlite and hydroton growing media with planting nutrients “Z”. The edible weight of the harvest test shows that the treatment combination of perlite and nutrient “Z” has the highest average, i.e., 59 g per plant.
ISSN: 0126-0537Accredited First Grade by Ministry of Research, Technology and Higher Education of The Republic of Indonesia, Decree No: 30/E/KPT/2018
Cite this as: Gabriel, A. A., & Shafri, M. H. (2022). The effect of nutrition and planting media on the productivity and quality of baby kai-lan (Brassica oleracea var. alboglabra) cultivated using nutrient film technique system. AGRIVITA Journal of Agricultural Science, 44(3), 490-499. http://doi.org/10.17503/agrivita.v44i3.2810
The Effect of Nutrition and Planting Media on the Productivity and Quality of Baby Kai-Lan (Brassica oleracea var. alboglabra) Cultivated Using Nutrient Film Technique System
Azmi Alvian Gabriel*) and Muhammad Hadziq Shafri
Universitas Internasional Semen Indonesia, Gresik, East Java, Indonesia
consider the completeness of the elements as well.
The more full the ingredients contained in the nutrition, the higher the selling price of nutritional products will be. The non-uniform quality of healthy products in the market impacts the quality of hydroponic plants, so it is necessary to test the available nutrient solutions to get the best quality of hydroponic products (Amalfitano, Del Vacchio, Somma, Cuciniello, & Caruso, 2017).
Using water as a medium for dissolving nutrients in hydroponic planting techniques requires a planting medium that can function as a place to support plants and attach plant roots. In addition, the planting medium must absorb water-contained nutrients easily so plants can benefit fully. There were several growing media on the market, such as cocopeat, rockwool, perlite, hydroton, sand, husk charcoal, and others (Kennard, Stirling, Prashar, & Lopez-Capel, 2020). Selection of the right planting medium will affect the productivity and quality of plant products (Ferguson, Saliga III, &
Omaye, 2014; Kozai, Niu, & Takagaki, 2020).
In addition, consideration of external factors such as sunlight intensity, the humidity of cultivation space, and the availability of oxygen in the water must be considered to optimize plant growth. The development of information technology can facilitate the application of control systems in various fields, including the agricultural industry. Using a control system in agriculture allows an increase and standardization of the quality of agricultural products because it is no longer dependent on uncontrollable external conditions. The use of wireless equipment can be used to monitor and control environmental conditions to match the characteristics of the cultivation environment required by plants. The technology is expected to present a smart agricultural system capable of conditioning plant growth factors in humidity and lighting (Kozai, Niu, & Takagaki, 2020).
Although the effects of nutrition and planting media have already been documented in the lettuce type, little investigation has been carried out on the baby kai-lan (Brassica oleracea var. alboglabra). Therefore, we planned research aimed at defining both the most effective nutrient type and growing media application on the yield and quality performances of baby kai-lan grown using the nutrient film technique system.
MATERIALS AND METHODS
Research on baby kai-lan yield and quality performances was carried out from 2019 to 2020. The research was conducted at the Process Laboratory, Campus C of Universitas Internasional Semen Indonesia (UISI), Gresik, Indonesia. Meanwhile, product quality testing was carried out at the
Physical Chemistry Laboratory at Campus A UISI and the Chemistry Laboratory, Faculty of Agriculture, Universitas Brawijaya, Malang, Indonesia. The research was a factorial experiment using a randomized block design repeated three times with two variables: the types of nutrition and the planting media. Plant nutrition variables include three types of hydroponic nutritional products in the market labeled
“X”, “Y”, and “Z”. ABmix nutrition labeled X and Z are solid, which need to be diluted first to be applied as hydroponic plant nutrition. In contrast, ABmix nutrition labeled Y is liquid. The application of all hydroponic nutrition follows the guidelines for use stated on each nutritional product’s label.
The four types of planting media are perlite, cocopeat, hydroton, and rockwool. The kai-lan seeds that had been sown for about one week were then transplanted to the net pots, filled with different planting media. When transferred to the NFT system, the physical and morphological analysis was performed by measuring the number of leaves, leaf width, population and root length, and edible weight every five days. In addition, growth observations were carried out starting from the day after planting (DAP) (0, 5, 10, 15, 20, 25).
The plants harvested on the 25th DAP were observed and tested with the parameters of observations: plant height, number of leaves, stem diameter, productivity, and comparable product quality. In addition, harvest observations were done on the 25th DAP with parameters of leaf area per plant, root length, total fresh weight, fresh root weight, and fresh consumption weight. Besides that, there were supporting parameters, including observation of the acidity of the water media, nutrient concentration, and the growing media. Finally, the data obtained from the observations were processed using the F test at the 5% level.
RESULTS AND DISCUSSION
Interaction of Nutrients and Planting Media on Plant Growth
The treatments using variations of nutrient solutions and planting media showed an interaction with plant growth based on several parameters. First, the nutrients strongly influenced the hydroponic NFT method and plant media used. The selected nutrients must support growth optimally, so a complete nutrient solution is needed to accelerate growth (Petropoulos, Chatzieustratiou, Constantopoulou, & Kapotis, 2016).
Kikowska et al. (2014) stated that the nutrient intakes of hydroponic plants are obtained externally. The nutrient solution consists of macro and micro salts
made in stock solutions A and B. Stock solution A contains N, K, Ca, and Fe elements, while stock solution B contains P, Mg, S, Mn, Cu, Na, Mo, and Zn elements. In this study, the dosage was the same for the three types of nutrients used, adjusted to the nutritional needs of the kai-lan plants. Plant growth data were obtained by conditioning the number of doses as a control treatment, as described in Table 1 and Table 2.
The lack of certain nutrients will inhibit plant growth. Likewise, excess nutrition will disrupt growth and production results (Li, Li, Tang, & Gu, 2018). The right amount of nutrition will affect the quality of the product from the organoleptic aspect. Meanwhile, the planting media play a role in providing and storing the nutrient needs. It functions as a place for the growth of plant roots and to supply food (Wahome, Oseni,
Masarirambi, & Shongwe, 2011). Planting media that can bind a good solution will provide plants with the necessary nutrients.
Table 1 shows that the plants with a reasonable growth rate based on the parameters of leaf number, leaf width, and root length were P3M1, P1M2, and P3M1/P3M2, respectively. It shows that using
“Z” nutrients has advantages over other nutrients supporting plant growth. Meanwhile, the media that significantly influence plant growth are hydroton and perlite. Both types of planting media have good porosity so that they can increase air circulation at the roots. Besides that, the media has an excellent ability to store nutrients. According to Krisnawati, Triyono, &
Kadir (2014), aeration and good humidity in a planting medium support optimal root growth.
Table 1. The mean plant leaf width and root length of baby kai-lan on the interaction of nutrient solution treatment and planting medium at the 25th DAP
Treatment Number of leaves (sheet) Leaf width (cm) Root length (cm)
P1M1 (X-Hidroton) 7.00bc 10.00bc 7.00ab
P1M2 (X-Perlite) 7.00bc 12.33e 7.00ab
P1M3 (X-Cocopeat) 6.67ab 8.67a 6.67a
P1M4 (X-Rockwool) 7.33bc 11.00de 7.33ab
P2M1 (Y-Hidroton) 6.67ab 9.67ab 15.00cd
P2M2 (Y-Perlite) 6.67ab 9.67ab 14.67cd
P2M3 (Y-Cocopeat) 6.67ab 8.67a 13.00c
P2M4 (Y-Rockwool) 6.33a 9.33ab 16.33cd
P3M1 (Z-Hidroton) 8.33d 10.33bcd 18.67d
P3M2 (Z-Perlite) 8.00d 10.83cd 18.67d
P3M3 (Z-Cocopeat) 7.00bc 9.33ab 16.00cd
P3M4 (Z-Rockwool) 7.00bc 9.67ab 16.67cd
Remarks: Numbers in the same column followed by the same letter, not significantly different based on the LSD test at 5% level
Table 2. Average total fresh weight and edible weight on the interaction of nutrient solution treatment and growing media
Treatment Total fresh weight (g) Edible weight (g)
P1M1 (X-Hidroton) 53.33bcd 45.33cd
P1M2 (X-Perlite) 66.00ef 52.33de
P1M3 (X-Cocopeat) 42.33a 34.00a
P1M4 (X-Rockwool) 49.00abcd 39.00abc
P2M1 (Y-Hidroton) 44.00ab 34.33ab
P2M2 (Y-Perlite) 46.00abc 37.67abc
P2M3 (Y-Cocopeat) 41.33a 33.67a
P2M4 (Y-Rockwool) 55.33cd 40.33abc
P3M1 (Z-Hidroton) 52.00abcd 42.00bc
P3M2 (Z-Perlite) 73.00f 59.33e
P3M3 (Z-Cocopeat) 47.33abcd 39.33abc
P3M4 (Z-Rockwool) 56.67de 41.67bc
Remarks: Numbers in the same column followed by the same letter, not significantly different based on the LSD test at 5% level
To further assess the effect of nutrition and planting media on the quality of producing yields, the final weight and the edible product should be observed after the harvest (Table 2). Based on these data, the highest average fresh weight and edible yield are found in the P3M2 treatment, respectively, 73 g and 59.33 g per plant. Meanwhile, the second highest fresh weight and fresh edible yield are obtained from the P1M2 treatment, with respective volumes of 66.00 g and 52.33 g per plant.
This information shows that the planting medium of perlite has the best effect on plant growth, followed by the result of plant nutrition “Z”, which offers better
impacts than other nutrients used in the experiment.
The nutrient solution influences plant growth, as shown in the plant growth graph (leaf width) in Fig. 1. Meanwhile, Fig. 2 shows the average number of the yielded leaves. The physiological changes in leaves indicate an increase in growth in all parts of the plant with the division and enlargement of each plant cell. The leaves of plants function as photosynthetic locations for processing and forming growth energy in plants. This increases along with the increasing width and number of leaves (Huang, Huang, Li, Yin, & Jiao, 2021; Lei & Engeseth, 2021;
Lu et al., 2022; Sublett, Barickman, & Sams, 2018).
Fig. 1. Effect of nutrient application on the mean leaf width (cm): (a) nutrient X; (b) Y nutrition; (c) Z nutrition
The addition of the dimensions and number of leaves indicates the adequacy of the element nitrogen provided by the nutrient solution. Dewi, Rahayu, & Bashri (2019) state that the consumption of nitrogen in sufficient quantities will accelerate the growth of roots, stems, and leaves in plants. The high average leaf width was also influenced by the effectiveness of lighting received by plants. With good lighting, the nutritional processing activity obtained by plants will run optimally along with the photosynthetic activity.
The concentration of nutrient solutions can affect plants’ absorption of nutritional elements. The concentrations in the three types of solutions range from 1025 to 1510 ppm (Table 3). The amount of ppm value suitable for kai-lan ranges from 1100 ppm, which can encourage the speed of plant growth both on leaf width, number of leaves, roots, and plant’s fresh weight (Kikowska et al., 2014). Meanwhile, nutrients’ acidity (pH) is at 5.35-5.84 (Table 3).
Therefore, the ideal acidity for kai-lan ranges from pH 5.00-7.00. According to Ding et al. (2018) and Singh, Dunn, & Payton (2019), the optimal pH value will facilitate the absorption of nutrients to support plant growth. Therefore, using a multilevel NFT
planting system does not significantly affect the conditions of planting parameters, including acidity, ppm of nutrients, and temperature at each planting level.
The use of planting medium affects plant roots.
The planting medium for hydroponic NFT systems must absorb and distribute plant nutrients properly to maximize the yield’s quality and accelerate growth. The planting medium serves as a foothold for roots, a place for root growth, and supports the absorption of nutrients needed. According to Li et al. (2009), using different types and characteristics of planting mediums will affect root growth and development differently. The treatment using perlite planting medium showed the best results in terms of average length and weight of the plant roots, followed by hydroton, rockwool and cocopeat. The use of perlite as a planting medium can store plant nutrients properly, provide sufficient moisture to plant roots, and have a neutral pH. Besides that, the size of perlite resembles gravel with small dimensions so that the media’s surface area is large enough to interact with plant roots (Asaduzzaman et al., 2013).
Fig. 2. Effect of nutrition and planting media on the average number of leaves (observation day 25th) Table 3. Concentration and acidity of nutrient solutions
Nutrient EC (ppm)
5 DAP 10 DAP 15 DAP 20 DAP 25 DAP
X 1025 1089 1103 1375 1465
Y 1085 1115 1167 1510 1406
Z 1057 1101 1036 1446 1456
Nutrient pH
5 DAP 10 DAP 15 DAP 20 DAP 25 DAP
X 5.71 5.63 5.83 5.76 5.46
Y 5.57 5.49 5.55 5.45 5.35
Z 5.71 5.68 5.84 5.64 5.54
Fig. 3. Effect of planting medium on (a) average length and (b) root weight (observation day 25th)
Based on the results of all treatments, the kai- lan root is at an average length of 7.00 to 18.67 cm (Fig. 3.a). The kai-lan taproot can reach a length of 40 cm, with fibrous roots that can reach a length of 25 cm (Hirani & Li, 2021). Meanwhile, the fresh weight of the roots is in the range of 8.00 to 15.00 g. This condition indicates good and healthy root conditions in the baby kai-lan plant. Perlite medium can store nutrient solutions and has good drainage to adjust the nutritional needs of plants and reduce the possibility of root and stem rot. According to Rosalina et al. (2019), a porous planting medium has a balanced number of macro and micropores, so the air circulation produced is good with high water absorption. Moisture and good aeration of a medium are necessary for maximum root growth. In other words, the suitable planting medium will affect the effectiveness of fertilization or absorption of nutrient solutions. This is in line with
Son, Park, Kim, Yoo, & Nho (2021) and Soratto, Job, Fernandes, Assunção, & Fernandes (2020) statement claiming that a hydroponic growing medium must have the ability to bind water easily, have good aeration and drainage, and have a soft texture that is easily penetrated by plant roots.
Effect of Treatments on Nutritional Content of Product
Baby kai-lan is in high demand and enjoyed by the community because it is delicious and crunchy.
This commodity has good business prospects, given the increasing public interest in consuming healthy food products. In addition, baby kai-lan can also be used as a remedy for various diseases because it contains carotenoids (Hirani & Li, 2021). The results of testing the nutritional content of baby kai-lan products in multiple treatments can be seen in Table 4.
Table 4. Baby kai-lan nutrition content per 100 grams in various treatments Treatment Energy(Cal) Protein
(g) Fat
(g) Carbohydrate
(g) Fiber
(g) Water
(%) Phosphor
(P) (%) Calcium
(Ca) (%) Fe (ppm)
P1M1 45.47a 3.65 0.43 6.75 1.35 82.51 0.95 1.94 421.90
P1M2 46.88cde 3.79 0.48 6.85 1.40 81.88 0.88 2.40 317.90
P1M3 46.33c 3.75 0.45 6.82 1.37 80.33 0.91 2.19 2176.90
P1M4 46.05b 3.70 0.45 6.80 1.37 79.58 0.99 2.19 2922.70
P2M1 45.88a 3.75 0.40 6.82 1.37 80.48 0.97 2.65 1559.80
P2M2 46.57cd 3.82 0.41 6.90 1.38 81.90 0.80 1.77 1019.70
P2M3 46.62cde 3.77 0.46 6.85 1.37 81.94 0.73 1.84 1045.00
P2M4 46.76cde 3.85 0.44 6.85 1.36 81.61 0.89 1.84 1157.20
P3M1 47.49fg 3.98 0.45 6.88 1.38 81.52 1.25 1.32 1221.00
P3M2 48.87hi 4.21 0.47 6.95 1.39 80.70 1.32 1.69 1269.30
P3M3 47.16cdef 3.95 0.44 6.85 1.38 81.70 1.25 1.45 975.70
P3M4 48.60h 4.20 0.48 6.87 1.36 80.97 1.26 1.69 1170.20
Control 35.00 3.00 0.40 6.80 1.20 78 mg 56 mg 230 mg 2 mg
Table 5. Baby Kai-lan Hedonic Test Average
Sample Code Treatment Parameter
Texture Taste Color Flavor
1. P1M1 3.53 3.43 3.67 3.03
2. P1M2 3.50 3.67 3.70 3.13
3. P1M3 3.43 3.60 3.47 3.10
4. P1M4 3.40 3.67 3.53 3.03
5. P2M1 3.43 3.23 3.23 3.13
6. P2M2 3.23 3.27 3.33 3.27
7. P2M3 3.40 3.33 3.23 3.23
8. P2M4 3.47 3.40 3.30 3.20
9. P3M1 4.00 3.97 3.73 3.40
10. P3M2 4.30 4.63 3.67 3.20
11. P3M3 3.73 3.87 3.50 3.33
12. P3M4 3.60 3.77 3.57 3.37
Remarks: hedonic scale 0 - 1.00 = very dislike; 1.01 - 2.00 = dislike; 2.01 - 3.00 = neutral; 3.01 - 4.00 = like; 4.01 - 5.00
= very like
There are complex nutrients in the baby kai- lan yields, which include protein, fat, carbohydrates, fiber, phosphorus (P), calcium (Ca), and iron (Fe) (Table 4). The protein content of baby kai-lan in all treatments was in the range of 3.65 to 4.21 g.
It shows the value over control of 3.00 g (Hirani &
Li, 2021). The fat, carbohydrate, and fiber content of baby kai-lan are between 0.40-0.48 g, 6.75-6.95 g, and 1.35-1.40 g, respectively. This is following the control value for each parameter (Hirani & Li, 2021). At the same time, the average calorie value in each treatment was 45.47- 48.87 calories, which indicates a value higher than the control value of 35.00 calories (Hirani & Li, 2021; Li et al., 2022).
Based on the test results, it is found that the treatment of variations in planting media and the nutrients given have a significant effect on each parameter of the nutritional content of baby kai- lan even though the range of values for each test parameter is not much different. The use of varying planting nutrients greatly affects the quality of crop yields on various parameters of observation of the physical analysis and plant morphology (Aires, 2018; Nguyen, McInturf, & Mendoza-Cózatl, 2016;
Sapkota, Sapkota, & Liu, 2019; Song et al., 2015).
Organoleptic Test for Products
Organoleptic testing of the baby kai-lan harvest was carried out using the hedonic or the level of preference test. There were five hedonic scales used, namely: like very much, like, neutral, dislike, and dislike very much. The data analysis transformed the hedonic scale into a scale of 1 to 5. The hedonic test was conducted with 30 random housewife panellists. Organoleptic tests were carried out on four parameters: texture, taste, color, and aroma (Carli, Barone, Fogliano, Frusciante,
& Ercolano, 2011). The purpose of organoleptic testing with the hedonic test was to determine the level of preference for the texture, taste, color, and aroma parameters of baby kai-lan products. The average value of the panellists’ preference for each treatment is presented in Table 5.
The baby kai-lan hedonic test results on texture and taste parameters showed that the panellists preferred the P3M2 treatment with scores of 4.30 and 4.63, respectively. With this treatment, the baby kai-lan shows the crunchiest texture with a sweeter taste compared to the yields of other treatments. While the color and aroma parameters cannot be fully justified, the test treatment with the
best results considering the tendency of the color and aroma from all treatments, showed the same results.
CONCLUSION
Perlite is the best planting medium based on the results of tests. Perlite has good aeration properties for roots, which is not too humid and may cause mildew and mold on the roots. It has a neutral pH and is quite light. Meanwhile, product
“Z” nutrition has the most significant influence on the growth of the object of research. The treatment of variations in nutrition and growing media also influenced the quantity and quality of baby kai-lan yields. P3M2 showed the highest score for the baby kai-lan hedonic test on texture and taste parameters.
Nevertheless, the color and aroma parameters cannot be fully justified due to the insignificantly different results from all treatments.
ACKNOWLEDGEMENT
The authors were thankful to the Institute of Research and Community Services (LPPM) Universitas Pertamina and Universitas Internasional Semen Indonesia, which funded this research in the fiscal year 2019.
REFERENCES
Aires, A. (2018). Hydroponic production systems: Impact on nutritional status and bioactive compounds of fresh vegetables. In Md. Asaduzzaman, & T.
Asao (Eds.), Vegetables - Importance of Quality Vegetables to Human Health. IntechOpen.
https://doi.org/10.5772/intechopen.73011 Amalfitano, C., Del Vacchio, L., Somma, S., Cuciniello,
A., & Caruso, G. (2017). Effects of cultural cycle and nutrient solution electrical conductivity on plant growth, yield and fruit quality of
‘Friariello’ pepper grown in hydroponics.
Horticultural Science, 44(2), 91–98. https://doi.
org/10.17221/172/2015-HORTSCI
Asaduzzaman, Md., Kobayashi, Y., Mondal, Md. F., Ban, T., Matsubara, H., Adachi, F., & Asao, T. (2013).
Growing carrots hydroponically using perlite substrates. Scientia Horticulturae, 159, 113-121.
https://doi.org/10.1016/j.scienta.2013.04.038 Carli, P., Barone, A., Fogliano, V., Frusciante, L., &
Ercolano, M. R. (2011). Dissection of genetic and environmental factors involved in tomato organoleptic quality. BMC Plant Biology, 11, 58.
https://doi.org/10.1186/1471-2229-11-58
Dewi, S. K., Rahayu, Y. S., & Bashri, A. (2019).
The effectiveness of nutrient variation to hydroponic Caisim (Brassica juncea L.) growth. Journal of Physics: Conference Series, 1417, 012038. https://doi.org/10.1088/1742- 6596/1417/1/012038
Ding, X., Jiang, Y., Zhao, H., Guo, D., He, L., Liu, F., … Yu, J. (2018). Electrical conductivity of nutrient solution influenced photosynthesis, quality, and antioxidant enzyme activity of pakchoi (Brassica campestris L. ssp. Chinensis) in a hydroponic system. PLoS ONE, 13(8), e0202090. https://
doi.org/10.1371/journal.pone.0202090
Ferguson, S. D., Saliga III, R. P., & Omaye, S. T. (2014).
Investigating the effects of hydroponic media on quality of greenhouse grown leafy greens.
International Journal of Agricultural Extension, 02(03), 227-234. Retrieved from https://naes.
agnt.unr.edu/PMS/Pubs/309_2015_01.pdf Hirani, A. H., & Li, G. (2021). Genetic mapping,
quantitative trait analysis, and gene cloning in Brassica oleracea. In S. Liu, R. Snowdon, & C.
Kole (Eds.), The Brassica oleracea Genome (pp.
7-22). Compendium of Plant Genomes. Cham:
Springer. https://doi.org/10.1007/978-3-030- 31005-9_2
Huang, Y., Huang, Q., Li, J., Yin, Y., & Jiao, Z. (2021).
Photosynthetic physiology and molecular response mechanisms of Indica–japonica intersubspecific tetraploid rice seedlings to ion beams. Journal of Plant Growth Regulation, 40, 722–735. https://doi.org/10.1007/s00344-020- 10136-x
Kennard, N., Stirling, R., Prashar, A., & Lopez-Capel, E. (2020). Evaluation of recycled materials as hydroponic growing media. Agronomy, 10(8), 1092. https://doi.org/10.3390/
agronomy10081092
Kikowska, M., Thiem, B., Sliwinska, E., Rewers, M., Kowalczyk, M., Stochmal, A., & Oleszek, W.
(2014). The effect of nutritional factors and plant growth regulators on micropropagation and production of phenolic acids and saponins from plantlets and adventitious root cultures of Eryngium maritimum L. Journal of Plant Growth Regulation, 33, 809–819. https://doi.
org/10.1007/s00344-014-9428-y
Kozai, T., Niu, G., & Takagaki, M. (2020). Plant factory:
An indoor vertical farming system for efficient quality food production (2nd ed.). Academic Press. https://doi.org/10.1016/C2018-0-00969-X Krisnawati, D., Triyono, S., & Kadir, M. Z. (2014). Pengaruh
aerasi terhadap pertumbuhan tanaman baby
kailan (Brassica oleraceae var. achepala) pada teknologi hidroponik sistem terapung di dalam dan di luar greenhouse. Jurnal Teknik Pertanian Lampung, 3(3), 213-222. Retrieved from https://
jurnal.fp.unila.ac.id/index.php/JTP/article/
view/659
Lei, C., & Engeseth, N. J. (2021). Comparison of growth characteristics, functional qualities, and texture of hydroponically grown and soil-grown lettuce.
LWT, 150, 111931. https://doi.org/10.1016/j.
lwt.2021.111931
Li, C., Li, Y., Cui, D., Li, Y., Zou, G., Thompson, R., … Yang, J. (2022). Integrated crop-nitrogen management improves tomato yield and root architecture and minimizes soil residual N.
Agronomy, 12(7), 1617. https://doi.org/10.3390/
agronomy12071617
Li, Q., Li, X., Tang, B., & Gu, M. (2018). Growth responses and root characteristics of lettuce grown in aeroponics, hydroponics, and substrate culture.
Horticulturae, 4(4), 35. https://doi.org/10.3390/
horticulturae4040035
Li, Y.-Y., Yu, C.-B., Cheng, X., Li, C.-J., Sun, J.-H., Zhang, F.-S., … Li, L. (2009). Intercropping alleviates the inhibitory effect of N fertilization on nodulation and symbiotic N2 fixation of faba bean. Plant and Soil, 323, 295–308. https://doi.org/10.1007/
s11104-009-9938-8
Lu, T., Yu, H., Wang, T., Zhang, T., Shi, C., & Jiang, W.
(2022). Influence of the electrical conductivity of the nutrient solution in different phenological stages on the growth and yield of cherry tomato.
Horticulturae, 8(5), 378. https://doi.org/10.3390/
horticulturae8050378
Nguyen, N. T., McInturf, S. A., & Mendoza-Cózatl, D.
G. (2016). Hydroponics: A versatile system to study nutrient allocation and plant responses to nutrient availability and exposure to toxic elements. Journal of Visualized Experiments, 113, 54317. https://doi.org/10.3791%2F54317 Petropoulos, S. A., Chatzieustratiou, E., Constantopoulou,
E., & Kapotis, G. (2016). Yield and quality of lettuce and rocket grown in floating culture system. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 44(2), 603–612. https://doi.
org/10.15835/nbha44210611
Rosalina, F., Gafur, M A. A., Irnawati, I., Soekamto, M.
H., Sangadji, Z., & and Kahar, M. S. (2019).
Utilization of compost and zeolite as ameliorant on quartz sand planting media for caisim (Brassica juncea) plant growth. Journal of Physics:
Conference Series, 1155, 012055. https://doi.
org/10.1088/1742-6596/1155/1/012055
Sapkota, S., Sapkota, S., & Liu, Z. (2019). Effects of nutrient composition and lettuce cultivar on crop production in hydroponic culture.
Horticulturae, 5(4), 72. https://doi.org/10.3390/
horticulturae5040072
Singh, H., Dunn, B., & Payton, M. (2019). Hydroponic pH modifiers affect plant growth and nutrient content in leafy greens. Journal of Horticultural Research, 27(1), 31-36. https://doi.org/10.2478/
johr-2019-0004
Son, Y.-J., Park, J.-E., Kim, J., Yoo, G., & Nho, C. W.
(2021). The changes in growth parameters, qualities, and chemical constituents of lemon balm (Melissa officinalis L.) cultivated in three different hydroponic systems. Industrial Crops and Products, 163, 113313. https://doi.
org/10.1016/j.indcrop.2021.113313
Song, N., Wang, J., Wang, Q., Zheng, J., Chen, J., Shi, S., & Li, F. (2015). Effect of a new kind of liquid fertilizer on yield, quality and safety of greenhouse chinese cabbage. Agricultural
Research, 4(1), 57–62. https://doi.org/10.1007/
s40003-014-0145-3
Soratto, R. P., Job, A. L. G., Fernandes, A. M., Assunção, N. S., & Fernandes, F. M. (2020). Biomass accumulation and nutritional requirements of potato as affected by potassium supply. Journal of Soil Science and Plant Nutrition, 20, 1051–
1066. https://doi.org/10.1007/s42729-020- 00192-3
Sublett, W. L., Barickman, T. C., & Sams, C. E. (2018).
The effect of environment and nutrients on hydroponic lettuce yield, quality, and phytonutrients. Horticulturae, 4(4), 48. https://
doi.org/10.3390/horticulturae4040048
Wahome, P. K., Oseni, T. O., Masarirambi, M. T., & Shon- gwe, V. D. (2011). Effects of different hydropon- ics systems and growing media on the vegetative growth, yield and cut flower quality of gypsoph- ila (Gypsophila paniculata L.). World Journal of Agricultural Sciences, 7(6), 692-698. Retrieved from https://citeseerx.ist.psu.edu/viewdoc/down- load?doi=10.1.1.415.1470&rep=rep1&type=pdf
