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Crop physiological response to nutrient solution electrical conductivity and pH in an ebb-and-flow hydroponic system
Abstract
Small-scale hydroponic and aquaponic crop production is increasingly common in urban areas of the US and growers have questions about which system and crops to use. Hydroponic nutrient solution contains water soluble nutrients, electrical conductivity (EC) is maintained between 1 and 3dSm-1, and target pH is between 5.5 and 6. In contrast, plants in aquaponic systems are fertilized by aquaculture effluent, which is characterized by lower EC (less than 1dSm-1) and a target pH near 7.2. Duplicate greenhouse trials were conducted between 2013 and 2015 to assess the growth, yield, quality, and potential gross returns of four crops - basil (Ocimum basilicum L.), kale (Brassica oleracea L.), chipotle pepper (Capsicum annuum L.), and cherry tomato (Solanum lycopersicum L.) - grown in a recirculating ebb-and-flow system with nutrient solution EC and pH levels commonly observed in hydroponic (high EC-low pH) and small-scale aquaponic (low EC-high pH) systems. Solution pH and EC, plant height, and leaf greenness data were collected regularly throughout crop growth, and yield and percent soluble solids (°Brix) data were collected at harvest. Crops grown in the high EC-low pH solution approached a greater final height, but relative growth rate was not different from the low EC-high pH solution. Leaf chlorophyll content, estimated from leaf greenness, was up to 37% lower in the low EC-high pH solution. Marketable yield of basil and kale was reduced by 44% and 76% in the low EC-high pH solution, respectively. Yield loss in tomato and pepper was less severe (<32%), but still significant. Observed yield reductions were greater than previous comparisons of floating-raft aquaponic and hydroponic systems, which demonstrates the importance of root to nutrient solution contact area and fertigation frequency when using low EC-high pH nutrient solution (e.g., aquaculture effluent). Differences may also suggest there are components of aquaponic solution not tested in this mechanistic study (e.g., organic metabolites and alternative nutrient forms or ratios) that may contribute to crop growth and yield in aquaponics. On a per plant basis, kale (10.62) and cherry tomato (9.16) grown in the high EC-low pH solution provided the greatest potential gross returns, but farm-scale net profit potential will depend on many factors including plant spacing and input costs.
... A variety of materials, such as coir, rockwool, and expanded clay, can serve as support structures for plants and mediums for nutrient delivery. Recent studies explore the impact of different growing media on factors like yield, water use efficiency, and overall plant health (Mahjoor et al., 2016) [29] (Wortman, 2015) [30] (Niu et al., 2015) [31] . ...
... A variety of materials, such as coir, rockwool, and expanded clay, can serve as support structures for plants and mediums for nutrient delivery. Recent studies explore the impact of different growing media on factors like yield, water use efficiency, and overall plant health (Mahjoor et al., 2016) [29] (Wortman, 2015) [30] (Niu et al., 2015) [31] . ...
Vertical hydroponic farming is an innovative approach to agriculture that seeks to address the challenges posed by urbanization and the growing global population. This method leverages vertical space and hydroponic techniques to grow plants indoors, offering a sustainable alternative to traditional farming. This review paper explores the fundamental principles of vertical hydroponic farming, including the various hydroponic systems and vertical structures employed. It discusses the significant advantages of this farming method, such as space efficiency, controlled environment agriculture, water conservation, reduced pesticide use, and year-round production. The paper also addresses the challenges faced by vertical hydroponic farming, including high initial investment costs, energy consumption, the need for technical expertise, and the limited variety of crops currently suitable for hydroponic systems. The economic viability and environmental impact of vertical hydroponic farming are analyzed, considering factors like market demand, operational efficiency, and energy consumption. The future of vertical hydroponic farming, discussing the potential for expanding crop varieties, integrating renewable energy sources, supportive urban agriculture policies, and the importance of community engagement and education has also been discussed. This study aims to provide a comprehensive understanding of vertical hydroponic farming's current state, challenges, and future prospects, emphasizing its potential to revolutionize sustainable food production in urban environments.
... Particularly, the strength of EC and pH of water are key factors of a potential aquaponic system. They greatly influence physiological and morphological activities of plants as well as their nutrient uptake (Wortman, 2015;Delaide et al., 2016;Kim et al., 2022). Moreover, adjustment of EC and pH is a necessary step in aquaponic systems to promote nitrification and ensure fish health (Tyson et al., 2007). ...
... The pH of aquaponic water plays a crucial role in fish health through oxidation of NO 2 and NH 4 in this system (Chen and Ma, 2006). The range of pH also affects nutrient uptake of plants (Wortman, 2015). In this study, the pH fluctuated in all treated water with a range of 4.2 to 6.2 (Fig. 2B). ...
... g/plant) was obtained from DWCHS which is not commonly used on a commercial scale. Wortman (2015) found that the relative vegetative growth rates of basil, kale, tomato, and pepper in recirculated aquaponics (low EC + high pH) did not differ from plants grown in conventional hydroponics (high EC + low pH). ...
... But the very first harvest was obtained from DWCHS, three days earlier than DWCAS. Imais (1987) values found in previous studies (Logendra, 2001;Wortman, 2015). ...
New tendencies in farming techniques which include a composite agricultural production system have evolved as solutions for uninterrupted food supply. Production of high-yielding good-quality tomato (Solanum lycopersicum L.) is one of the leading challenges. This study aimed at evaluating the growth, yield, and fruit quality of hybrid tomato (Umagna), cultivated in non-circulating aquaponics and conventional hydroponics systems. A unique and innovative non-recirculating deep water culture aquaponics system (DWCAS) was developed as a prerequisite for high productivity comparable to current stand-alone fish/plant facilities. Including DWCAS, two other conventional hydroponics systems were compared during the study; the deep water culture hydroponics system (DWCHS) and the open bag system (OBS). The assessment of the production systems was based on the growth behavior, tomato yield, and quality. The maximum yield was observed for the DWCHS (2.81 kg/plant) followed by DWCAS (2.4 kg/plant). The least yield was observed for the OBS (2.34 kg/plant). The results demonstrated the highest average fruit weight (169.44 g/fruit) and marketable yield (2802 g) produced by DWCHS. There was no difference in plant dry matter content among production systems. The fertilizer use efficiency was increased by 11.7% and 85.86% in favor of the DWCAS and DWCHS, respectively. The total rainwater use efficiency was also increased in DWCHS.
... As well as, pH and EC in aquapinic water should be maintained based on types of plant and fish in this system (Tyson et al., 2007). Notably, the pH and strength of the EC of the solution act as key factors for a successful aquaponics system, influencing the physiology and yield of the plants (Wortman, 2015;Delaide et al., 2016;Jeong et al., 2020). A higher pH value (more than 7) inhibits plants from up taking essential nutrients, such as iron, from the solution (Rakocy, 2012). ...
... The pH of the nutrient solution plays an important role in fish health due to the oxidation of NH 4 and NO 2 in the aquaponic system (Chen and Ma, 2006). Differences in the solution pH affect plant nutrient uptake outcomes (Wortman, 2015). During the treatment period here, the pH of the water fluctuated in all treatments in the range of 6.9 to 4.0 (Fig. 2B). ...
... Resh [3] stated that five aspects must be considered when formulating nutrients: plant variety, growth stage, marketable yield, weather, and climate [4]. The development of the plants was also observed to be impacted by various hydroponic systems [5]. Each element is present in a distinct concentration in each nutritional solution. ...
... There still needs to be more knowledge on appropriate and efficient hydroponics nutrients. Urban farmers need this knowledge to boost productivity and optimize profits [5]. ...
This study examines the yield and quality of packcoy and lettuce with several nutritional formulations. The study was
conducted with a 2 x 2 factorial arrangement based on a completely randomized design (CRD) with three replications. This study used
Packcoy and Lettuce plants as the first factor, then four nutritional formulations: AB mix (control), Hoagland & Arnond, and Hewitt,
Huett's Lettuce. The research focused on observing the weight of dry plant biomass, crop yields, and plant quality as seen from the
accumulation of chlorophyll and carotenoid leaves. The results showed that Hoagland & Arnond's nutritional formulations increased
plant leaf area weight, plant dry weight, and plant production yield. Meanwhile, Packcoy plants, given AB mix nutrition, could
accumulate high levels of leaf chlorophyll and carotenoids. Hoagland & Arnond's nutritional formulation is ideal because it optimizes
plant production and accumulates relatively better chlorophyll and carotenoids.
Keywords: Hydroponics, Horticulture, Nutrient, Yield Quality
... This range indicates a relatively stable ionic concentration in the water, which is essential for the health of both plants and fish in aquaponic systems. As noted, optimal conductivity levels are crucial for nutrient absorption and overall system balance [41]. The slight increase in conductivity in the v-2 variant could be attributed to the accumulation of ions over time; specific interactions with microelements [42,43] determined that electrical conductivity significantly affects fish production. ...
This study explores the effects of varying exposure times of microelement fertilization on hydrochemical parameters, plant growth, and nutrient content in an aquaponic system cultivating Capsicum annuum L. (pepper) with Cyprinus carpio (Common carp L.). It also investigates the potential of visible-near-infrared (VIS-NIR) spectroscopy to differentiate between treated plants based on their spectral characteristics. The findings aim to enhance the understanding of microelement dynamics in aquaponics and optimize the use of VIS-NIR spectroscopy for nutrient and stress detection in crops. The effects of microelement exposure on the growth and health of Cyprinus carpio (Common carp L.) in an aquaponic system are investigated, demonstrating a 100% survival rate and optimal growth performance. The findings suggest that microelement treatments, when applied within safe limits, can enhance system productivity without compromising fish health. Concerning hydrochemical parameters, conductivity remained stable, with values ranging from 271.66 to 297.66 µS/cm, while pH and dissolved oxygen levels were within optimal ranges for aquaponic systems. Ammonia nitrogen levels decreased significantly in treated variants, suggesting improved water quality, while nitrate and orthophosphate reductions indicated an enhanced plant nutrient uptake. The findings underscore the importance of managing water chemistry to maintain a balanced and productive aquaponic system. The increase in root length observed in treatments 2 and 6 suggests that certain microelement exposure times may enhance root development, with treatment 6 showing the longest roots (58.33 cm). Despite this, treatment 2 had a lower biomass (61.2 g), indicating that root growth did not necessarily translate into increased plant weight, possibly due to energy being directed towards root development over fruit production. In contrast, treatment 6 showed both the greatest root length and the highest weight (133.4 g), suggesting a positive correlation between root development and fruit biomass. Yield data revealed that treatment 4 produced the highest yield (0.144 g), suggesting an optimal exposure time before nutrient imbalances negatively impact growth. These results highlight the complexity of microelement exposure in aquaponic systems, emphasizing the importance of fine-tuning exposure times to balance root growth, biomass, and yield for optimal plant development. The spectral characteristics of the visible-near-infrared region of pepper plants treated with microelements revealed subtle differences, particularly in the green (534-555 nm) and red edge (680-750 nm) regions. SIMCA models successfully classified control and treated plants with a misclassification rate of only 1.6%, Citation: Sirakov, I.; Stoyanova, S.; Velichkova, K.; Slavcheva-Sirakova, D.; Valkova, E.; Yorgov, D.; Veleva, P.; Atanassova, S. Exploring Microelement Fertilization and Visible-Near-Infrared Spectroscopy for Enhanced Productivity in Capsicum annuum and Cyprinus carpio Aquaponic Systems. Plants 2024, 13, 3566. https://doi.org/ 10.3390/plants13243566 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/license s/by/4.0/). Plants 2024, 13, 3566 2 of 18 highlighting the effectiveness of the spectral data for plant differentiation. Key wavelengths for distinguishing plant classes were 468 nm, 537 nm, 687 nm, 728 nm, and 969 nm, which were closely related to plant pigment content and nutrient status. These findings suggest that spectral analysis can be a valuable tool for the non-destructive assessment of plant health and nutrient status.
... In our study, the floating bed condition was found to favor various fertility-related parameters, including moisture content, electrical conductivity (EC), and pH. Several reports reveal that EC drives optimal growth by enhancing photosynthetic efficiency (Ding et al. 2018) and nutrient uptake in soilless hydroponic vegetable cultivation (Moya et al. 2017;Wortman 2015). Notably, our observations revealed a high level of EC in the organic matter present in the floating bed. ...
In the waterlogged regions of Bangladesh, climate change exacerbates agricultural challenges, particularly for sensitive crops like chili pepper (Capsicum annuum L.). This two-season study evaluated the growth and development of eight chili pepper varieties (four cultivated in the summer and four in the winter) in floating beds and traditional soil-based farming systems. Morphological traits, root development, and reproductive traits of the chili plants were evaluated. The results showed that floating beds significantly (p < 0.05) enhanced shoot morphology, root development, and reproductive traits during the winter season but had no effect in the summer season. Floating beds provided better moisture retention , nutrient availability, and pH stability, contributing to increased shoot and root growth and ultimately leading to superior reproductive traits. Although the effects of variety were less pronounced , significant differences in specific traits were observed within the seasons. Among the summer varieties, V2 (BARI Morich-2) performed best in the soil bed for plant height, fruit number, and yield, while V3 ("Anol-1701") performed best in floating beds. In the winter, V7 ("Jhilik") exhibited superior performance in floating beds, particularly for reproductive traits. The winter variety V7 achieved the highest production under floating conditions, with 3.2067 kg m-2 , representing a 655.3% increase over soil-based beds, while the summer variety V3 yielded 0.4321 kg m-2 , a 53.5% increase. Additionally, a significant interaction between bed type and variety was observed for the number of fruits and yield in summer, and leaf area in winter, indicating the synergistic effects of these factors on chili growth. ARTICLE HISTORY
... In our study, the floating bed condition was found to favor various fertility-related parameters, including moisture content, electrical conductivity (EC), and pH. Several reports reveal that EC drives optimal growth by enhancing photosynthetic efficiency (Ding et al. 2018) and nutrient uptake in soilless hydroponic vegetable cultivation (Moya et al. 2017;Wortman 2015). Notably, our observations revealed a high level of EC in the organic matter present in the floating bed. ...
... Plants will absorb nutrients in the form of nitrates and nitrites, which trigger the formation of ammonia from food and fish waste. Aquaponic are divided into six systems, namely the wick system [2], water culture system [6], drip irrigation system [7,8], aeroponic system [9,10], ebb and flow system [11,12], nutrient film technique (NFT) [5,13]). This research aims to compare the water quality and quality of catfish with organoleptic tests cultivated in permanent ponds without an aquaponics system and nonpermanent ponds using composite plastic ponds and the aquaponics method. ...
Catfish is one of the most popular in Indonesia because it is easy to maintain. Catfish can be cultured in ponds or together with plants, known as an aquaponic system. This study aimed to compare water quality and the quality of catfish cultured using conventional systems in concrete ponds and an aquaponic systems in plastic fiber ponds. This study has the results of water quality testing showing a difference in the ammonia value of 3 ppm in concrete pond using conventional system and 0.5 ppm in plastic fiber ponds using an aquaponic system. Meanwhile, the results of organoleptic test show that catfish cultured using an aquaponic system provide higher value comparison to the conventional system. Catfish cultured with an aquaponic system is better than conventional systems in ponds.
... In this regard, several reports have indicated that crops irrigated with high levels of EC nutrient solution show significant reduction in plant biomass [26,53,54]. Therefore, electrical conductivity indicates the strength of the nutrients in the nutrient solution [55], as the fertilizer salts break into cations and anions. Consequently, a higher nutrient content results in higher electrical conductivity. ...
Strawberries are sensitive to abiotic stresses such as salinity, high levels of electrical conductivity, and nutrient imbalances. The mutualistic endophytic fungus Piriformospora indica has significant potential to be used in improving crop production under adverse conditions, with a large host range. However, greenhouse production requires novel tactics to improve the efficiency of saline water irrigation in areas with limited freshwater resources. This study was conducted at the National Research and Development Center for Sustainable Agriculture (Estidamah), KSA, to investigate the impact of P. indica colonization on the growth, photosynthesis traits, productivity, and fruit quality of Fragraria x ananassa Duch cv. Festival strawberry grown in pots and irrigated with two electrical conductivity (EC) nutrient solutions of 1.5 and 3.0 dS/m. The results showed that higher-EC-nutrient solution clearly reduced growth and early yield and improved vitamin C, TSS, and anthocyanin of strawberry in comparison to low-EC-nutrient solution. On the other hand, P. indica colonization significantly increased plant height, shoot fresh weight, root length, and early yield of plants grown under high-EC-nutrient solution with no impact on fruit quality. Obviously, the symbiosis between strawberry roots and P. indica enhanced chlorophyll content, photosynthetic rate, stomatal conductance, and transpiration rate, as well as antioxidant activity such as proline, malondialdehyde, catalase, superoxide dismutase, and peroxidase under higher-EC-nutrient solution. Our study indicated that P. indica might be used as a sustainable tool for strawberry production in arid and semiarid zones, to mitigate the negative impacts of higher-EC-nutrient solution.
... Commercial settings typically employ ebb and flow systems for the development of seedlings. Gross returns from ebband flow system yields of kale and cherry tomatoes were higher than those from basil and chipotle peppers (Wortman, 2015). Ebb and flow irrigation methods increased tomato root characteristics and stem diameter by 9-45% compared to top sprinkle irrigation (Wang et al., 2022). ...
... The BS treatment showed the minimum change in the EC value and decreased day by day during the observation, where the highest value was 0.49 mS and the lowest was 0.25 mS. Meanwhile, for the BC installation, the EC [30]. All treatments except BB met the EC requirements for aquaponics. ...
The development of aquaponic cultivation in Indonesia remains limited despite its potential to significantly boost farmers’ and communities’ income. In aquaponics, fish are regularly fed, while plants solely rely on nutrients derived from leftover feed and fish waste, without external supplementation. Biofilters play a crucial role in aquaponic systems, providing a growth medium for microorganisms that convert fish feces’ ammonia into nitrates, essential for plant nutrition. In general, biofilters use bioball material, so as to optimize the biofilter, this study compares the effectiveness of different materials, namely activated charcoal, shells, and coconut fiber, when incorporated into bioball biofilters within aquaponic systems. The research was conducted on an aquaponic installation featuring an NFT system utilizing PVC pipes. The experiment involved 45 tilapia fish, each measuring 7-11 cm and weighing 10-15 grams, alongside red lettuce plants planted in 10 holes per pipe, with 6 replications. After 45 days from planting, the plants were harvested, and observations were made on both plant and fish growth. The growth of red lettuce plants in the biofilter installation with shells addition (BS) showed the best results based on parameters such as plant height, leaf width, plant dry weight, and shoot:root ratio. The installation with coconut fiber addition (BS) showed the best results in terms of number of leaves. BA installation with activated carcoal addition (BA) showed the best results in terms of number of Leaf chlorophyll. The highest percentage of survival for Nile tilapia was observed in the BS and BA installation with a rate of 88.89%, followed by 78.57% in the BC installation, and 60.46% in the BB installation.
... A CE é uma das medidas utilizadas para mensurar o equilíbrio osmótico para os peixes (Yanes et al., 2020) e avaliar a disponibilidade de nutrientes para as plantas (Oliveira et al., 2010). A CE na solução aquapônica comumente se encontra baixa (<1.000 µS cm -1 ) (Yanes et al., 2020) e a literatura sugere, para o cultivo de plantas, CE entre 1.000 e 3.000 µS cm -1 (Wortman, 2015). Portanto, considera-se que as densidades D2 e D3 são mais adequadas para fornecer nutrientes para o componente vegetal no sistema aquapônico. ...
Resumo A cultura da alface representa a hortaliça folhosa mais cultivada e preferida no Brasil. Todavia, há escassez de informações científicas que atestem o potencial produtivo desta cultura em sistemas aquapônicos. Portanto, objetivou-se avaliar o desempenho de variedades de alface cultivada em sistema aquapônico Nutrient Film Technique (NFT) sob diferentes densidades de estocagem de tilápia-do-Nilo (Oreochromis niloticus). O experimento foi realizado em esquema fatorial 4x3, contendo três repetições, correspondente a: variedades de alface (A-Lídia, B-Elisa, C-Vanda e D-Milena) e densidades de estocagem (D1-30, D2-60 e D3-90 peixes m-3). Após a colheita, avaliaram-se os indicadores de desempenho agronômico: altura de planta (AP), diâmetro de parte aérea (DPA), número de folhas (NF), massa fresca foliar (MFF) e radicular (MFR), massa seca foliar (MSF) e radicular (MSR) e produtividade (PDT). Também foram monitorados os parâmetros de água como oxigênio dissolvido (OD), condutividade elétrica (CE), potencial hidrogeniônico (pH), N-amoniacal (NH4+), temperatura da água (Ta) e da casa de vegetação (ΔT). Foram aplicados aos conjuntos de dados, testes de normalidade, homocedasticidade, variância e comparações múltiplas (todos a 5% de probabilidade). As variedades lisas (Lídia e Elisa) apresentaram maiores valores de DPA e NF, conferindo uma característica relevante ao consumo in natura. As variedades crespas (Vanda e Milena) conferiram maior PDT, características relevantes para o processamento agroindustrial. A densidade de estocagem intermediária (D2) proporcionou melhor desempenho das alfaces e uma qualidade de água apropriada. Logo, concluiu-se que as variedades de alface cultivadas em sistema aquapônico apresentaram diferentes aptidões mercadológicas e que a densidade de estocagem de 60 peixes m-3 proporcionou maior rendimento agronômico às alfaces.
... The rhizomes of 3-year-old mother plants were divided into 4 parts and planted in 25 L hydroponic pots and soil. In hydroponics EBB and Flow system was used [15]. The experiment was set up with three treatments: 1. hydroponic with growing medium volcanic slag (VS); 2. hydroponic with growing medium volcanic slag and gravel in a 1:1 ratio (VS+G), 3. soil (S) which served as the control group. ...
Rhubarb (Rheum rhabarbarum L.) is a popular springtime vegetable known for its vibrant red stalks and tart flavor. This study explores the intriguing biochemical profile of rhubarb and highlights its potential health benefits. Hydroponic systems (volcanic slag and volcanic slag with gravel significantly increased rhubarb yield (both fresh and dry weight) by 2.6-6.0 times compared to traditional soil, especially in June and July. Rhubarb grown hydroponically also produced 1.6-1.8 times more petioles per plant, each with 1.6 times the fresh weight and 1.1 times the dry weight of soil-grown petioles. Compared to soil, hydroponics significantly increased the levels of extractive substances (1.2-3.2 times), flavonoids (1.4-3.7 times), and phenols (1.2-4.0 times). The research evaluated antioxidant activity, with hydroponically grown rhubarb demonstrating superior performance, particularly in the volcanic slag + gravel plants, which exhibited the strongest antioxidant activity. In contrast, the soil-grown plants displayed the lowest antioxidant activity. According to the FRAP analysis, 1 gram of plant dry mass recovered more iron in the soil-grown variant, followed by the volcanic slag variant. These findings suggest that hydroponic systems, especially those using the volcanic slag substrate, hold promise for cultivating rhubarb enriched with health-promoting compounds in the Ararat Valley.
... Electrical conductivity (EC) is a measure of the dissolved salts in a solution, serving as a crucial factor for nutrient uptake in hydroponic systems. Typically, the EC value is maintained between 1.5 and 2.0 dS m −1 in such systems (Wortman, 2015). Ceustermans (1987, 1988) recommended maintaining the EC range between 2.0 and 2.5 dS m −1 in their studies for hydroponics. ...
... The higher pH and lower EC in the SVT solution contributed to lower biomass production ( Table 1). The findings coincide with the outcomes of Wortman [25], who found that plants such as Ocimum basilicum L., Brassica oleracea L., Capsicum annuum L., and Solanum lycopersicum L. showed a reduction of up to 76% in yield when grown in nutrient solutions with low EC and high pH levels. The EC of the SVT solution was 1.292 mS/cm. ...
Organic products are gaining popularity due to their positive impact on human health and the environment. While hydroponics is commonly used in vegetable production, it relies on mineral fertilizers derived from limited and non-renewable resources. As a result, farmers are actively seeking sustainable farming solutions. This study comprehensively evaluated the effectiveness of vermi-liquids (organic nutrient solutions) as a replacement for conventional inorganic nutrient solutions in promoting growth and nutrient acquisition in Diplotaxis muralis plants in a controlled environment. The results showed that plant biomass and SPAD values of D. muralis grown in Hoagland solution and enhanced vermitea (vermitea having relatively low pH and high EC) were higher compared to standard vermitea (high pH and low EC). The findings also revealed improved nutrient assimilation of phosphorus, potassium, calcium, iron, manganese, copper, and zinc in the enhanced vermitea plants. The heavy metal contents in D. muralis leaves were evaluated, too, and they were found to fall significantly below the safe threshold, rendering them safe for human consumption. However, the standard vermitea, with its high pH and low EC, performed poorly as a hydroponic solution. This research suggests that enhanced vermitea can completely replace chemical nutrient solutions in hydroponic agriculture. This substitution could lead to reduced production costs and improved product quality.
... This information guides growers in adjusting nutrient concentrations to maintain optimal levels for plant health. The proper balance of electrical conductivity ensures that plants receive the right amount of nutrients for robust growth (Wortman, 2015). ...
Hydroponics, a soilless cultivation method, has emerged as a transformative
approach to modern agriculture. This abstract explores the principles, benefits, and
applications of hydroponics. In hydroponic systems, plants receive essential
nutrients dissolved in water, with their roots suspended in an inert medium. This
precise nutrient delivery allows for optimal plant growth and development,
eliminating the variability associated with traditional soil-based agriculture. The key
advantage of hydroponics lies in its efficient use of resources. Hydroponics promotes
faster growth rates and higheryields compared to traditional farming methods. The
controlled environment enables growers to fine-tune factors such as nutrient levels,
pH, and temperature, optimizing conditions for plant growth. This precision
contributes to consistent crop quality and reduces the reliance on chemical inputs,
aligning with principles of sustainable and environmentally friendly agriculture. The
versatility of hydroponics extends beyond traditional farming limitations. The
abstract concludes by acknowledging the challenges associated with hydroponics,
including initial setup costs and the need for technical expertise.
... A pH that is too high or too low can limit the availability of essential nutrients, leading to nutrient imbalances and impaired physiological processes (Resh, 2022, p. 16). Wortman (2015) showed that high pH and low EC values can reduce the marketable yield of marketable Basil by up to 76%. He looked at pH levels of 5.5, 6 and 7.2. ...
... However, challenges such as root rot, algae, and mold have been identified with this system, necessitating the development of a modified version with a filtering unit. Additionally, incorporating computer automation is a viable option to ensure the efficient operation of this system (Wortman 2015). The main advantages of a drip system over other types of hydroponics systems are that it conserves more water and can survive unexpected equipment or power failures. ...
The growing population and the effects of climate change have made it increasingly difficult to provide enough food, as fertile land becomes scarce. Traditional farming methods are inefficient and require large amounts of natural resources, such as land, water, and fertilizers. Maintaining the desired nutrient levels during crop growth is also a challenge. To address these issues and achieve food security, many countries are adopting smart farming concepts that utilize IoT platforms and artificial intelligence. One such technique is soilless cultivation, a cutting-edge method that allows for the growth of fruits, vegetables, and medicinal plants without soil. Soilless cultivation is highly regarded worldwide for its ability to maximize crop production in a productive and intensive manner. It utilizes closed growing systems that enable the collection and reuse of drainage, minimizing water and nutrient losses to the environment. By integrating IoT sensors, continuous monitoring of crop growth is made possible. Hydroponics, aeroponics, and aquaponics are the commonly used soilless cultivation techniques, employing nutrient solutions and inert media to support plant growth. These advancements in technology offer promising prospects for agriculture, but also present challenges. This chapter explores the current technological developments, potential opportunities, and obstacles in the field of soilless cultivation.
... De manera similar, Yang y Kim (2019) reportan valores de fosfatos para acuaponía entre 24.7 y 24.9 mg L -1 y 74.5 mg L -1 para hidroponía en la producción de seis especies de vegetales y hierbas incluyendo la acelga. Para una disponibilidad y absorción óptimo de fosfatos (PO4 + ) por parte de las plantas, se recomienda que el pH en los sistemas acuapónicos se mantenga cercano a 7 (Rakocy et al. 2006, Wortman 2015, por lo que se considera que las condiciones en este estudio fueron las adecuadas para ese propósito. ...
La hidroponía es la tecnología de la agricultura sin suelo, en la que las plantas crecen en un medio acuático. Mientras que la acuaponía es un sistema de producción de alimentos en rápido crecimiento que integra la hidroponía con la acuicultura (cultivo de peces). El objetivo de este estudio fue comparar la producción de acelga (Beta vulgaris var. Cicla L.) mediante un sistema hidropónico típico y un sistema acuapónico de producción de tilapia (Oreochromis niloticus) en invernadero. Se utilizaron seis sistemas de recirculación independientes para comprobar la producción por triplicado. Un análisis de regresión lineal simple indicó que la tasa de producción de hojas difirió de forma significativa entre sistemas (p < 0.05), ya que en el hidropónico se obtuvieron 3.46 hojas semana-1, mientras que en el acuapónico fue de 1.53 hojas semana-1. La biomasa vegetal aumentó 53.91 g semana-1 en el tratamiento hidropónico y 38.24 g semana-1 en el acuapónico, aunque dichas tasas de producción no difirieron significativamente (p>0.05). No se detectaron diferencias significativas en las concentraciones de amonio (NH4+), nitrito (NO2-), y fosfato (PO4+) en ambos tratamientos; pero se encontraron diferencias significativas para nitratos (NO3-) entre sistemas (p < 0.05). La producción de acelgas en el sistema hidropónico fue mayor que en el sistema acuapónico en cuanto al número de hojas y la biomasa.
... De manera similar, Yang y Kim (2019) reportan valores de fosfatos para acuaponía entre 24.7 y 24.9 mg L -1 y 74.5 mg L -1 para hidroponía en la producción de seis especies de vegetales y hierbas incluyendo la acelga. Para una disponibilidad y absorción óptimo de fosfatos (PO4 + ) por parte de las plantas, se recomienda que el pH en los sistemas acuapónicos se mantenga cercano a 7 (Rakocy et al. 2006, Wortman 2015, por lo que se considera que las condiciones en este estudio fueron las adecuadas para ese propósito. ...
La hidroponía es la tecnología de la agricultura sin suelo, en la que las plantas crecen en un medio acuático. Mientras que la acuaponía es un sistema de producción de alimentos en rápido crecimiento que integra la hidroponía con la acuicultura (cultivo de peces). El objetivo de este estudio fue comparar la producción de acelga (Beta vulgaris var. Cicla L.) mediante un sistema hidropónico típico y un sistema acuapónico de producción de tilapia (Oreochromis niloticus) en invernadero.
... pH signifies the acidity or alkalinity of the solution, while EC measures nutrient concentration. Regular testing and adjustment of these parameters are essential to ensure optimal plant growth and nutrient absorption [17]. Since hydroponics often takes place indoors, artificial lighting becomes imperative to facilitate photosynthesis. ...
In now a day’s soil based cultivation is major difficulties due to different man made reason such as urbanization and industrialization. Hydroponic system such as the deep flow technique, nutrient film technique and aeroponic systems are essential tools in plant factories more over sudden natural disaster, climate change and unlimited use of chemical for agriculture purpose lead to reduction in soil fertility and quality. That’s why scientist have evolved a new alternative approach to the agriculture system is called as hydroponic system. Hydroponic is a technique of growing plants in a water based and nutrient rich solution by hydroponic large number of crops for plants can be grown easily. The quality of yield and nutritive value of end products produced by hydroponically is generally greater than the natural soil based cultivation. This type of cultivation is diseases free, eco-friendly and growing popularity across the whole world including the both developed and developing countries.
... The experiment was carried out in an experimental field, Ararat Valley, Armenia, involving automatic irrigation hydroponic equipment (with a density of 6 plant m -2 ) using the EBB and Flow hydroponic system (Wortman, 2015). A treatment group consisted of cultivation in soil conditions. ...
Article type: Moringa oleifera Lam. is a well-known medicinal plant and food source. It is rich in bioactive substances, has several pharmacological properties , and is an introduced species to Armenia. This study aimed to evaluate moringa for adaptability to Armenian climatic conditions while assessing its antioxidant and antibacterial activities in different cultivation systems. Moringa plants were grown in soil and hydroponic systems (on specific substrates: volcanic slag, gravel, volcanic slag mixed with gravel). We examined growth characteristics, yield, antioxidant activity, and antibacterial properties. The results showed that moringa can adapt to the Armenian climate. It is important to note that leaf dry mass increased by 1.6-1.7 fold in hydroponic-grown plants compared to soil-grown plants, regardless of the growth substrate. We observed a higher antioxidant activity in plants that grew on gravel only and gravel mixed with volcanic slag substrates. A comparative study of the antibacterial activity of moringa leaf water extract revealed that the plant extract (5000 µg mL-1) in hydroponic conditions suppressed the growth of gram-positive (Enterococcus hirae) and gram-negative (Escherichia coli) bacteria in 24 hours. Soil-grown plants had similar extracts by concentration that inhibited the growth of gram-negative bacteria. Thus, moringa plants adapted to the Armenian climate. The plants performed better in the hydroponic system than in the soil system. This superiority in performance appeared in plant growth, yield , antioxidant activity, and antibacterial properties. Abbreviations: Gravel (G), Moringa oleifera (MO), Useful biomass (UBM), Volcanic slag (VS)
... Since the EC value represents the nutrient concentration of the solution, in most previous studies and general practice, the monitoring of the nutrient solution is based on the measurement of EC few times daily (Wortman 2015;Majid et al. 2021). Nutrient concentration alteration occurs over time due to plant nutrient uptake, crop growth, and evaporation. ...
Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. It produces significantly higher yields compared to conventional agriculture despite its higher energy consumption. The success of a hydroponic system relies on the composition of the nutrient solution, which contains all the essential mineral elements necessary for optimal plant growth and high yield. This review delves into the discussion of enhancing nutrient solution management strategies across different hydroponic systems. The aim of this review is to discuss various techniques for monitoring nutrient solutions in order to improve nutrient use efficiency (NUE) and water use efficiency (WUE). The conventional approach of monitoring the hydroponic nutrient solution using electrical conductivity measurement may not provide precise information about ion concentrations, potentially resulting in poor yields or excessive fertilizer usage. To overcome these limitations, alternative management strategies have been developed to enable more accurate monitoring and efficient management. One such strategy is the nitrogen-based approach, where nitrogen concentration becomes the primary controlled element in the nutrient solution and leads to WUE and NUE development by prolonging nutrient solution recirculation. Furthermore, various methods have been devised to improve nutrient solution strategies. These include using ion-selective electrodes to measure individual ions in the hydroponic nutrient solution, using sensors to monitor substrate moisture content, estimating water requirements, and implementing programmed nutrient addition methods. In addition to introducing different management techniques to optimize hydroponic performance, this review provides a better understanding of hydroponic systems.
... In controlled environments, hydroponic systems such as floating system are commonly used for leafy vegetables cultivation (Cantliffe and Hochmuth, 2018). In hydroponic cultivation, chemical characteristics of nutrient solutions (such as EC and pH) are fundamental for plants growth (Wortman, 2015). As reported in other previous research (Hashida et al., 2014;Raimondi et al., 2006), the ideal nutrient strength in a hydroponic solution depends on cultivation system, crop species, growth stage, and planting density, but is typically between 1 and 3 dS m -1 . ...
... Crops were grown independently in a sponge medium serving as artificial soil, and the necessary nutrients were provided through a closed nutrient film technique system where the electrical conductivity and pH values without a separate nutrient solution supply device. Generally, EC and pH values below or above the optimal range can impede water and nutrient uptake in crops, thereby inhibiting growth and potentially inducing diseases [29]. Therefore, the nutrient solution was manually managed to maintain an appropriate concentration by measuring the EC and pH values at 2-day intervals through standard sampling. ...
Plant phenotyping has been widely studied as an effective and powerful tool for analyzing crop status and growth. However, the traditional phenotyping (i.e., manual) is time-consuming and laborious, and the various types of growing structures and limited room for systems hinder phenotyping on a large and high-throughput scale. In this study, a low-cost high-throughput phenotyping system that can be flexibly applied to diverse structures of growing beds with reliable spatial–temporal continuities was developed. The phenotyping system was composed of a low-cost phenotype sensor network with an integrated Raspberry Pi board and camera module. With the distributed camera sensors, the system can provide crop imagery information over the entire growing bed in real time. Furthermore, the modularized image-processing architecture supports the investigation of several phenotypic indices. The feasibility of the system was evaluated for Batavia lettuce grown under different light periods in a container-type plant factory. For the growing lettuces under different light periods, crop characteristics such as fresh weight, leaf length, leaf width, and leaf number were manually measured and compared with the phenotypic indices from the system. From the results, the system showed varying phenotypic features of lettuce for the entire growing period. In addition, the varied growth curves according to the different positions and light conditions confirmed that the developed system has potential to achieve many plant phenotypic scenarios at low cost and with spatial versatility. As such, it serves as a valuable development tool for researchers and cultivators interested in phenotyping.
... Multiple elements have been identified for inclusion in hydroponic nutrient solutions for lettuce growth, including nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), sulphur (S), magnesium (Mg), zinc (Zn), boron (B), manganese (Mn), and molybdenum (Mo) (Chekli et al., 2017;Domingues et al., 2012). Macronutrient and micronutrient concentrations significantly affect lettuce growth, yield, and quality (Fallovo et al., 2009;Song et al., 2020;Wortman, 2015). To manage nutrient solutions in automated, controlled growing environments, recommendations based on suitable thresholds for solution pH and electrical conductivity are often used (Savvas & Adamidis, 1999;Singh & Dunn, 2017); however, these measurements do not measure actual nutrient uptake by the plant or nutrient concentrations in plant tissue, which instead is normally measured by destructive sampling and laboratory analysis. ...
Effective management of plant essential nutrients is necessary for hydroponically grown lettuce to achieve high yields and maintain production. This study investigated in situ hyperspectral imaging of hydroponic lettuce for predicting nutrient concentrations and identifying nutrient deficiencies for: nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S). A greenhouse study was conducted using 'Salanova Green' lettuce grown with controlled solution treatments with varying macronutrient fertility rates of 0, 8, 16, 32, 64, and 100% each for N, P, K, Ca, Mg, and S. Plants were imaged using a hyperspectral line scanner at six and eight weeks after transplanting; then, plant tissues were sampled, and nutrient concentrations measured. Partial least squares regression (PLSR) models were developed to predict nutrient concentrations for each nutrient individually (PLS1) and for all six nutrient concentrations (PLS2). Several binary classification models were also developed to predict nutrient deficiencies. The PLS1 and PLS2 models predicted nutrient concentrations with Coefficient of Determination (R 2) values from 0.60 to 0.88 for N, P, K, and S, while results for Ca and Mg yielded R 2 values of 0.12e0.34, for both harvest dates. Similarly, plants deficient in N, P, K, and S were classified more accurately compared to plants deficient in Ca and Mg for both harvest dates, with F1 values (F-scores) ranging from 0.71 to 1.00, with the exception of K which had F1 scores of 0.40e0.67. Overall, results indicate that both leaf tissue nutrient concentration and nutrient deficiencies can be predicted using hyperspectral data collected for whole plants.
... 통기성 및 생육이 양호하여 활용성이 매우높다 (An 등, 2007;Wortman, 2015). 비모란선인장을 비롯한 접목선인장 수경 재배 ebb and flow 재배 방식은 저면으로부터 일정시간 담수 하여 양 • 수분을 공급하는 방법에 생력트레이를 적용하여 배 지없이 재배할 수 있는 방법이다 (Hong 등, 2009;Hong 등, 2005). ...
... The pH of the solution was maintained at a range of 5.5-6.5 with the addition of a base, potassium hydroxide (KOH) and nitric acid when it gets too high 30 . The electrical conductivity (EC) is a measure of the dissolved salts in a solution, which is another important factor for nutrient uptake in hydroponic systems, and EC value is maintained between 1.5 and 2.0 dS m − 1 in hydroponic systems 31 . Ceustermansn (1987, 1988) 32,33 have found the EC of Hoagland solution to be 2.2 dS m − 1 and recommended maintaining the EC range between (2.0-2.5 dS m − 1 ) in their studies for hydroponics. ...
Hydroponic systems have the potential for being one of the most promising sustainable alternative methods of food production, where they confer the advantages of producing higher yields with better control over plant growth. The main purpose of this study is to determine differences in growth rates, sensory attributes and nutrient uptake upon growing lettuce ( Lactuca sativa L.) in various hydroponic subsystems at two different plant spacings. We investigated the interaction of different effects on lettuce growth in four hydroponic subsystems, Deep Water Culture ((DWC), Nutrient Film Technique (NFT), Media- Bed system (MB) and Sandponic (SP), at two different plant densities, at narrow planting spacings (20 x25 cm), and larger planting spacings (24 x 25 cm). Our findings show that cultivation methods and planting spacing greatly influence lettuce growth. Overall, the present study provides direct evidence that DWC and NFTs subsystems at both planting spacings performed the best in terms of giving higher yield production, higher plant growth parameters, and better sensory attributes compared to other cultivation systems. Lettuces grown in the DWC system had higher chlorophyll B (29.13 ± 0.82 mg/100 g), and carotene content (32.40 ± 1.27 mg/100 g) in narrow planting spacing and were the most preferred lettuces according to taste tests (52.4%).
This review paper of literature highlights role of Light Emitting Diode (LED) on the growth of plants under controlled conditions of greenhouse farming particularly hydroponics. "Internet of Things (IOT)" is a system of interconnected computing devices, sensors, objects, microcontrollers, and cloud servers that can transmit data across a network and control other devices remotely without human intervention. Light Emitting Diode (LED) is a more efficient, versatile, lasts longer, highly energy-efficient, directional, narrow light spectrum, low power consumption, and little heat production. Common LED colors include amber, red, green, and blue. Hydroponic grow lights are designed to mimic the natural light that plants need for photosynthesis. Plants can only use the spectrum of visible light to produce photosynthesis, and this narrow spectrum (400 to 700 nanometer) is recognized as the Photosynthetically Active Radiation (PAR). The development and growth of diverse plant species can be influenced differently by a variety of colored LED lights. LED illumination provides an efficient way to improve yield and modify plant properties. Therefore, LED systems plays an important role in controlling morphological, genetic, physiological, chemical properties, increasing the synthesis of a variety of beneficial secondary metabolites, and optobiological interactions of plants in greenhouse farming. In general, red and blue light is essential for maximizing the photosynthesis process due to their strong absorption by the plant chlorophyll molecules. LED illumination sources are increasingly being utilized to enhance the growth rate of vegetables and herbs cultivated in greenhouses worldwide. LED illumination spectrum manipulation could enable significant morphological adaptations, and identification of the wavelength ranges is required to increase the plant photosynthesis process.
The electrical energy crisis is a problem faced by the Batu Kacang Village Community, related to the high demand for energy distribution, The limited access to electricity for the people of Batu Kacang Village means that public facilities in the form of lighting have not been fully accommodated, The scope of the program is limited, this research does not reach far into the operational development, maintenance and further development stages of an innovative green energy system, Optimization of the green energy transition in this research will be measured by three indicators, namely, activity, productivity and sustainability, The method used is capacity building, observation of component performance and systematic recording of measuring data, experimental research methods referring to references related to Microhydro Power Plants, The results show, the initial voltage is 12 volts with a current of 0.34 amperes, at the 4th to the 8th hour the current in the battery remains stable, namely 0.32 amperes and there is a decrease in the current at the 9th hour with a current of 0.27 amperes. or a decrease in current of 0.05 amperes. In the following hours the battery current decreased continuously from 0.26 amperes to 0.13 amperes or a decrease of 0.13 amperes, from 0.13 decreased to 0.09 and decreased again to 0.05 in the 12th hour or decreased by 0.04 amperes. The final voltage on the battery is 8.0 volts or 66% of the battery’s full capacity.
Against the backdrop of climate change, soil loss, and water scarcity, sustainable food production is a pivotal challenge for humanity. As the global population grows and urbanization intensifies, innovative agricultural methods are crucial to meet rising food demand, while mitigating environmental degradation. Hydroponic and aquaponic systems, has emerged as one of these solutions by minimizing land use, reducing water consumption, and enabling year-round crop production in urban areas. This study aimed at assessing the yield, ecophysiological performance, and nutritional content of Lactuca sativa L. and Cichorium endivia L. var. crispum grown in hydroponic and aquaponic floating raft systems, with Oreochromis niloticus L. integrated into the aquaponic system. Both species exhibited higher fresh biomass and canopy/root ratios in hydroponics compared to aquaponics. Additionally, hydroponics increased the leaf number in curly endive by 18%. Ecophysiological parameters, such as the leaf net photosynthesis rate, actual yield of PSII, and linear electron transport rate, were also higher in hydroponics for both species. However, the nutritional profiles varied between the two cultivation systems and between the two species. Given that standard fish feed often lacks sufficient potassium levels for optimal plant growth, potassium supplementation could be a viable strategy to enhance plant development in aquaponic systems. In conclusion, although aquaponic systems may demonstrate lower productivity compared to hydroponics, they offer a more sustainable and potentially healthier product with fewer harmful compounds due to the reduced use of synthetic fertilizers, pesticides, and the absence of chemical residue accumulation. However, careful system management and monitoring are crucial to minimize potential contaminants.
Strawberries in Korea hold significant economic value, and their cultivation in hydroponics is
progressively expanding. This study explored the weighted evapotranspiration (WETc) of
strawberries grown on coir substrates, with the goal of optimizing irrigation volumes for improved
water management. ‘Sulhyang’ strawberries were transplanted at a plant density of 7.5 plants per m2
on September 15, 2022 into three different substrate types: V40D10 (40 L, dust: chip (v/v) = 10:0),
V30D10 (30 L, dust: chip (v/v) = 10:0), and V20D5 (20 L, dust: chip (v/v) = 5:5). The nutrient
solution was administered through an ISR-automated irrigation system. The schedule concentrated
irrigation from sunrise to 2 p.m. (accounting for 78–95% of the total daily irrigation volume),
resulting in higher drainage rates from 11 a.m. to 2 p.m. (50–70% of the day’s total drained volume).
The drainage rate for V20D5 was higher, at 40–50%. Total fruit weight per plant varied
significantly across the substrates, with V30D10 producing the highest weight (428.4 g) and
V40D10 the lowest (315.5 g). Despite lower dust ratios, V20D5 achieved performance comparable
to that of V30D10, with a total fruit weight of 350 g. An analysis of WETc on sunny days showed
a pattern of February > January > December, with hourly WETc revealing significant differences
among the substrates. On cloudy days, WETc remained below 5 g·plant-1, with cumulative values
ranging from 41 to 75 g·plant-1. Overall, the results suggest that the optimal daily irrigation volumes
per plant should be between 90 to 150 mL·plant-1 depending on the substrate volume and ratio.
These findings underscore the potential to minimize drainage and optimize irrigation in strawberry
hydroponics through precise, WETc-based scheduling, providing valuable insights for sustainable
cultivation practices.
Background: Plant seed oils are major renewable resources from nature that can be used in multiple applications. Oils and fats are a vital component of human diets. About 1/3 of the daily energy requirements of a healthy diet come from fats. Each branch of the food industry has its own demands for the fatty acid composition of seed oils. High amounts of polyunsaturated fatty acids are a requirement of healthy diets. However, food manufacturers need highly saturated fatty acids because they need oil that is resistant to high temperatures and oxidation. Soybean oil is second only behind palm oil as the most commercially abundant plant oil globally. Soybean has been recognized for its agricultural importance and their various positive effects on human health. Objective: to identify the quantitative changes of soybean fatty acids depending on the planting density and growing conditions in the Ararat Valley of Armenia. Methods: Soybean was grown in hydroponic and soil conditions of the Ararat Valley. The seeds were sown in the middle of April. Experiments were carried out in hydroponic equipment and soil with different planting densities (30, 50, 70 and 90 plants/m2). The oil content was measured by using the pulsed nuclear magnetic resonance method. The composition of fatty acids in seed oil was analyzed by chromatographic method on "Chromatec Crystal 5000" GC. Results: Oil content ranged from 19.6% to 24.4% in all variants. The maximum content was registered in soil with 30 plant/m2 planting density. Linoleic acid content ranged from 46.35 to 51.28% of the total fatty acid content, regardless of planting density and growing media. The content of linolenic acid ranged from 4.13 to 5.11% in all variants. The maximum content of ω-3 and the minimal content of ω-9 was recorded in hydroponics at 30 plants/m2 planting density. The highest percentage of stearic acid was observed in the soil variant with a planting density of 30 plants/m2. Interestingly, the variants did not differ in the total content of the 5 main fatty acids (98.84-98.95%). Growing medium had no significant effect on the total saturated fatty acids content; in all variants it ranged from 14.29% to 14.83%. Total unsaturated fatty acids content ranged from 85.2% to 85.7%. The hydroponic variant with a planting density of 30 plants/m2 had the lowest ratio of ω-6 and ω-3 fatty acids (10:1). Conclusion: Planting density and growing media had a significant influence on the content of monounsaturated and polyunsaturated fatty acids. Under hydroponic conditions the lowest content of monounsaturated and the highest content of polyunsaturated fatty acids were observed at the lowest planting density (30 plants/m2), which can be used as a functional food for daily consumption. Keywords: Glycine max (L.) Merr., soilless culture, ω-3, ω-6, ω-9, saturated acids.
This review paper of literature highlights the factors governing hydroponics and carbon foot print of vertical farming. Hydroponics is the art of growing plants without a soil but with using nutrient solution under hi-tech greenhouse controlled conditions in urban area. Because of the precise regulation of watering and feeding the plant, this method is superior to the traditional method. Hydroponics is influenced by many factors such as, light, oxygen level, carbon dioxide (CO2), nutrients supply, pH, electrical conductivity (EC), water, humidity, temperature, human labor, maintenance of the machinery, electricity, and water supply. Vertical farms generate an opportunity to grow crops in locations and altitudes that are not optimal for the plants growth. However, carbon foot print of hydroponic vertical farming is very high. In many cases, vertical farm production methods contribute more to greenhouse gas (GHG) emissions than products grown in the field and shipped long distances to market. Transportation of food materials results in carbon emissions from trucks burning fossil fuels. Initial investment to start hydroponic farming is very high. These greenhouses are energy intensive. Growing with green versions of conventional methods was more climate change advantageous than hydroponic systems. Therefore, hydroponic vertical farming are not going to reverse climate change. Hence degrading land and it is becoming un-farmable, then hydroponics is a good back up plan. Therefore, vertical farms, as they exist today, are not able to provide a sustainable solution to the global issues of decreasing availability of arable land and increasing food demands, even though they offer great benefits when compared to conventional farming methods. Vertical farms in urban cities will not solve food shortages or provide the calories that stave off hunger. This makes it difficult to justify the high environmental cost of lighting a hydroponic vertical farm and therefore, not a successful story.
This review paper of literature highlights the importance of greenhouse urban farming technology, hydroponics, aeroponics, aquaponics, vertical farming and applications of Internet of Things (IOT) technologies. The greenhouse farming is a well known modern agriculture technology for optimal plant growth. Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. Vertical farming is a popular trend in hydroponics that involves stacking multiple layers of plants in a vertical arrangement. This farming method saves space, reduces water usage, and increases yields per square foot of growing area. In comparison to conventional greenhouse cultivation, hydroponics requires less fertilizer, pesticides, and water due to the precise control over their distribution. The term "Internet of Things (IOT)" is a system of interconnected computing devices, sensors, objects, microcontrollers, and cloud servers that can transmit data across a network and control other devices remotely without human intervention. A better management of nutrient solution in hydroponic systems requires optimum pH, electrical conductivity (EC), or ions concentration. The three main greenhouse farming gases (GHGs) emissions in hydroponics hi-tech urban farming are nitrous oxide, methane and carbon dioxide (CO2). To measure the levels of CO2 in hydroponics, the more intermediate to advanced grower can use a CO2 monitoring and controllers system. Hydroponic vertical farming is in infancy in India. Although hydroponic vertical farming units for production of crops like strawberry, lettuce and other leafy vegetables, foliage and flowers are functioning in major metros of India. However, the organized hydroponic vertical farms for production of food crops are not available in India. Therefore, only a few successful hydroponic vertical farms have been built in India mainly due to the initial high price tag on construction and the cost of maintaining them afterwards. Another disadvantage is carbon footprint of hydroponic vertical farming is very high, and discourages its applications.
Aquaponic systems differ from hydroponics by a higher pH and higher concentrations of dissolved organic matter (DOM). This study assessed whether plant nutrient deficiencies in aquaponics are caused by lacking input of the deficient nutrients or their chemical saturation. Nine scenarios with nutrient concentrations based on Hoagland's solution and different pH (5.5, 6.5, 7.5) and DOM concentrations (0 mg L−1, 20 mg L−1) were constructed, representing theoretical hydroponic and aquaponic systems. Eventually, nutrient concentrations at equilibrium were calculated. In addition, a meta-analysis was conducted to assess whether nutrient concentrations reported in aquaponic studies could be predicted by equilibrium calculations. Theoretical results indicate that solubility thresholds cause deficiencies of P, Ca, Fe, and Cu at equilibrium due to the higher pH in aquaponics compared with hydroponics. Deficiencies in K and other plant nutrients are, meanwhile, likely caused by lacking supply through nutrient inputs at equilibrium. The presence of DOM can increase Fe and Cu solubility. However, equilibrium calculations could not predict nutrient concentrations found in literature. P was present at higher concentrations (max. 0.3 mmol L−1) than predicted (10−3–10−6 mmol L−1), indicating chemical equilibrium was not reached in the assessed systems (average hydraulic retention time = 17 d). Future studies should consider reaction rates. Furthermore, considering the low concentrations of dissolved P in all studies, a system scaling based on P instead of N might be considered.
The increasing population, its requirements for food, and the environmental impact of the excessive use of inputs make crop production a pressing challenge. Integrated nutrient management (INM) has emerged as a critical solution by maximizing nutrient availability and utilization for crops and vegetables. This review paper highlights the potential benefits of INM for various vegetables and field crops and explores the conceptual strategies, components, and principles underlying this approach. Studies have shown that a wide range of vegetables and field crops benefit from INM, in terms of increased yield and improvements in yield attributes, nutrient contents and uptake, growth parameters, and various physiological and biochemical characteristics. This paper discusses biostimulants, their categories, and their impact on plant propagation, growth, photosynthesis, seed germination, fruit set, and quality. Additionally, this review explores modern sustainable soilless production techniques such as hydroponics, aeroponics, and aquaponics. These cultivation methods highlight the advancements of controlled-environment agriculture (CEA) and its contribution to nutrient management, food security and minimizing the environmental footprint. The review concludes by proposing methods and fostering discussions on INM's future development, while acknowledging the challenges associated with its adoption. Finally, this review emphasizes the substantial evidence supporting INM as a novel and ecologically sound strategy for achieving sustainable agricultural production worldwide.
Background: Today, the rhubarb plant is selectively included in the diet. Rhubarb juice offers a unique flavor with a surprising range of potential health benefits. Rhubarb is rich in antioxidants, particularly anthocyanins, the pigments responsible for its red hue. These antioxidants are believed to possess anti-inflammatory and anti-bacterial properties, potentially aiding in the fight against various health concerns. Rhubarb juice is an excellent source of vitamins C, and K, crucial for bone health and blood clotting, and also contains vitamin A, contributing to healthy skin and vision. Context and purpose of this study: to investigate for the first time the cultivation of rhubarb (Rheum rhabarbarum) in the Ararat Valley of Armenia in both hydroponic and soil conditions. The research focuses on identifying the optimal growth period to maximize key quality indicators of rhubarb stalks and juice for food and medicinal applications: Brix value, juice density, total titratable acidity, and vitamin C content. Results: Hydroponic cultivation significantly (by three folds) increased the fresh weight of rhubarb petioles (stalks) compared to soil plants. The maximum accumulation of vitamin C in hydroponic plants was observed at the beginning (June) and end (September) of the growing season (19.4 and 17.3 mg%) respectively. However, there was not a significant difference in vitamin C content during July and August (14.3 and 14.0 mg% respectively). Soil plants showed the highest accumulation of vitamin C in September (41.5 mg%), exceeding the values in June by 1.2 times and from July to August by 1.5 times. Total titratable acidity showed seasonal variations: the highest acidity (1.2 to 1.3-fold higher) of hydroponic rhubarb juice was observed in July compared to other months. Soil-grown rhubarb reached peak acidity at the beginning of the growing season (approximately 1.2 times higher than in other months). The Brixo value and juice density peaked in July for hydroponic rhubarb and in August for soil rhubarb. Conclusion: This study highlights the potential of hydroponics for maximizing rhubarb yield and potentially influencing the vitamin C content and acidity profile throughout the growing season in Armenia. The results of further research could be used to optimize nutrient composition and environmental parameters for even greater control over rhubarb quality for food and medicinal purposes. Keywords: Vitamin C, Total titratable acidity, Brixo, Juice density
Basil is a medicinal herb and also a vegetable. Water and soil salinity is one of the major non-living stresses that reduce the growth and productivity of agricultural products all over the world. More than 800 million hectares of land around the world are saline and alkaline. In this experiment, five genotypes of basil (Iranian purple, black, ablaq, green and fiery red) were used as a split plot based on a completely random design with three replications, the main factor of which is salt stress at three levels (normal, medium stress and severe stress). and sub-factor including genotype (5 levels) were studied in pots and under greenhouse conditions in the crop year of 2023 in Kerman University of Advanced Education. The results showed that all the basil cultivars had the ability to withstand the salinity stress of 75 mM sodium chloride (moderate stress) and the values of vegetative and physiological characteristics were slightly reduced compared to the control treatment in such a way that no significant difference was observed in many cases. Application of salinity stress with the intensity of 135 mM sodium chloride (severe stress) caused the vegetative and physiological characteristics of all basil cultivars to decrease significantly and also at this stress level, the fiery basil cultivar was completely destroyed. In general, it can be stated that the basil cultivars used are highly sensitive to the level of more than 75 mM of salinity stress, and under salinity conditions, their vegetative and physiological characteristics are significantly reduced.
It has become increasingly difficult to feed the world's growing population with limited resources over time. This nutritious food should be prepared in a sustainable manner. In light of this, vertical farming has emerged as a viable option. Although vertical farming components are initially more expensive, they produce more food with fewer resources. This study focuses on various vertical farming structures before deciding on the best one. The main aspects to consider when designing a vertical farm are structure, nutrition media, lighting, and sustainability features. It discusses the suitable properties of the crop with respect to the optimized structure considering other important parameters like natural and human-made light. The major focus is on the crop yield and the best-suited environment for higher yield. This study provides a comprehensive overview of all of these aspects in order to improve understanding and design of the vertical farm.
Understanding the ecology of microorganisms is essential for optimizing aquaponics systems. Effects of pH and inoculum on ammonium removal and dynamics of microbial community composition from all compartments of lab-scale aquaponics systems were examined. Initial ammonium accumulation in systems with comammox-enriched inocula were 47% and 69% that of systems enriched with ammonia-oxidizing bacteria (AOB), with higher rates of ammonium removal and transient nitrite accumulation measured in the latter systems. By the end of operation, Nitrosomonas and Nitrosospira AOB were dominant nitrifiers in systems at pH 7.6–7.8, whereas comammox (Nitrospira) nitrifiers and plant growth-promoting microbes were abundant in systems operating at pH 5.8–6.0. Lower pH systems supported more robust plant growth with no significant effects on fish health. This study demonstrated functional redundancy of aquaponics microbiota, with selectivity of nitrifying taxa as a function of pH. The results suggest that inoculum and pH are important considerations for aquaponics system initiation and optimization.
Titanium dioxide nanoparticles (-NPs) are believed can enhance crop yield by accelerating the photosynthetic rate, infection control management, and competent catalyst for the decomposition of organic pollutants. The purpose of this research is to investigate the effect of titanium dioxide nanoparticles (-NPs) on L. sativa, lettuce growth in a hydroponic system using two different media: sponge and cocopeat. Hydroponic systems with optimum treatment factors, such as air temperature, humidity, light, pH of nutrient solution, and electrical conductivity (EC), were applied in this study to attain elevated yields within a short period of time. The results show that L. sativa without -NPs treatment produces an optimum growth pattern in terms of biomass, including fresh weight, dry weight, and height, with p < 0.05, especially when using cocopeat medium. Detailed observation found that -NPs treatment showed no significant difference between the leaf count and diameter on L. sativa. This study found that -NPs could act as an efficient organic catalyst for maintaining hydroponic nutrient quality. However, further findings indicate that -NPs could interfere with the nutrient absorption process from the roots, which might lead to off-color foliage, and plant stress. Further research is recommended to study the implication of -NPs on growth, nutrient absorption, and organic catalyst potential that is beneficial for plant growth.
Sub-irrigation of greenhouse crops has the potential to increase water and nutrient use efficiency; however, fertilizer salts that are not absorbed by the plants tend to accumulate in the substrate and eventually raise the substrate's electrical conductivity (EC). The objective of this study was to determine the optimum EC of the nutrient solution in sub-irrigated tomatoes to allow maximum yield. Total fruit yield was higher in sub-irrigated plants with solutions at 2.0 dS m −1 (5105 g per plant), and it was comparable to that obtained for drip-irrigated plants (4903 g per plant); however, the yield of fruits from the second truss was 37% higher in sub-irrigated than in drip-irrigated plants when the EC was 2.0 dS m −1. In contrast, at the end of the growing season, the yield of plants sub-irrigated with nutrient solutions of 2.0 dS m −1 was the lowest, being surpassed by 37% by that of plants treated with 1.4 dS m −1. The dry weight of vegetative plant parts was reduced in sub-irrigated plants, suggesting a shift in dry mass partitioning. Our results show that with sub-irrigation, the growing season should be started using nutrient solutions with higher EC, but eventually, this EC should be decreased to maintain proper substrate EC and high yield.
أدى النمو الهائل للسكان في العالم إلى زيادة الطلب العالمي على الغذاء والتوسع في النشاط الزراعي مما زاد الضغط على موارد المياه والتربة المتاحة والتي هي محدودة أصلاً. سيصبح من المستحيل إطعام سكان العالم في المستقبل القريب باستخدام نظم الزراعة التقليدية ومن المهم تحسين وتطوير الطريقة التي ننتج بها غذائنا باستخدام تقنيات إنتاج أكثر تقدمًا ومن الضروري زيادة إنتاج الغذاء من الأراضي الزراعية الحالية باستخدام مدخلات أقل لتقليل الضغط على الموارد الطبيعية وبدون تقويض قدرتنا على الاستمرار في إنتاج المزيد من الغذاء. تمثل الزراعة المائية الحل الأمثل وهي صناعة متنامية لم تصل بعد إلى كامل إمكاناتها وتم استخدامها بنجاح في زراعة مجموعة متنوعة من المحاصيل مثل الخس والطماطم والخيار والورقيات والأزهار. في الزراعة المائية تزرع النباتات دون استخدام للتربة كوسط للنمو وتزود بالعناصر الغذائية من خلال المحاليل المغذية. من مزايا الزراعة بدون تربة الغلة العالية في مساحة محدودة وتوفير في المياه والأسمدة ويمكن أيضًا استخدامها في الأماكن التي يستحيل فيها القيام بأي نشاط زراعي أو المناطق التي تتميز بتدهور شديد للتربة. يمثل نهج الزراعة بدون تربة استجابة مواتية نحو زراعة أكثر صداقة للبيئة وأداة واعدة في مجال الغذاء الأمن. حاولنا من خلال هذه المقالة المرجعية شرح الزراعة المائية فوائدها، تاريخها، مكوناتها، أنواعها ومستقبلها.
Aquaponics is currently undergoing a transformation into an intensive food production system. The initially applied systems focused on small-scale, fish-centric coupled (CAP, the aquaculture, and the hydroponic units are arranged in a single loop, and the water flows continuously from the fish tanks to the plant unit and back) aquaponics. More recently, the primary area of research interest has shifted toward larger-scale, plant-centric decoupled (aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently) systems, aiming to achieve greater economic benefits and employ more environmentally friendly practices. The objective of this study was to address gaps in the expansion of decoupled larger-scale aquaponics and to provide a comprehensive understanding of the water and nutrient flow in the system. For this purpose, experiments were performed in a greenhouse on CAP and DCAP systems, while this study also included measurements in a pure hydroponic system (HP). This study presents an assessment of the water and nutrient flow in four different crops: basil; cucumber; parsley; and tomato, all co-cultivated with a tilapia aquaculture system. Significant nutrient deficiencies and imbalances were identified in the CAP solution, leading to pronounced impacts on nutrient assimilation, particularly for fruiting vegetables. However, the average nutrient use efficiency (NUE) for nitrogen, phosphorous, potassium, and calcium was found to be 42% higher in the CAP treatment compared to HP and DCAP treatments. The nutrient solution in the DCAP treatment did not exhibit differences in water quality parameters and nutrient efficiency when compared to HP, resulting in similar effects on nutrient assimilation. Nonetheless, it was observed that DCAP plants exhibited superior NUE compared to HP plants.
Sustainable technological innovation can resolve the economic crisis that exists within a nation. Sri Lanka is a developing country with one out of every six people suffering from multidimensional poverty (UNICEF, 2022). The research serves as an experimental approach to achieve the Sustainable Development Goals [SDG] of no poverty (SDG No. 1), decent employment and economic growth (SDG No. 8), and industry, innovation, and infrastructure (SDG No. 9). The study involves conducting an experimental survey in the Mullaitivu District, focusing on three agricultural households selected from three Grama Niladhari Divisions (GNDs). The selection of these households was done using a stratified simple random sampling technique, ensuring representative coverage of the district. The study conducted utilizes technologically sophisticated interventions, referred to as a hydro greenhouse. This encompasses a greenhouse that is furnished with a hydroponic system, along with the inclusion of a photosynthetically active radiation diode. The control and experimental setups were reviewed for a period of 90 days. In conclusion, technological intervention in agriculture across war-torn regions has resulted in a significant increase in productivity, reduction in cost, and effective land and water utilization. Productivity was determined based on plant height and fruit yield. The households were trained on the construction and management techniques of the prototype named hydro greenhouse. To facilitate the commercialization of this method, it was proposed that the GND and DS officers leverage the results of the conducted experiment to obtain financial support from both governmental and non-governmental organizations.
The potential of Azospirillum brasilense to enhance basil growth under aquaponics system was evaluated using the three strains, i.e., Sp7, Sp7-S, and Sp245. Basil seedlings were inoculated with strains of A. brasilense a week after sowing and before transplanting. Impacts of inoculation on some parameters associated with plant growth, and physiological and metabolic activities were evaluated at seedling stage and at harvest of marketable plant size from aquaponics system. Likewise, impacts of inoculation on the existing bacterial communities were assessed at the end of each stage. At seedling stage, inoculated seedlings produced longer (90 %) roots and taller (19 %) plants with more developed (25 %) and bigger (61 %) leaves. As a result, seedling fresh and dry biomasses were increased by 79 and 44 %, respectively, particularly for those seedlings inoculated with Sp7 and Sp245. Some of the plant metabolic activities were altered by inoculation such as elevated levels of enzyme peroxidase activity and total phosphorus content. In aquaponics, plants previously inoculated with the strains also showed superior growth performance. For instance, basil leaf area, fresh herbage yield, and root weight were increased by inoculation up to 27, 11 and 11 %, respectively. Inoculation also enhanced peroxidase activity (73 %), endogenous plant indole-3-acetic acid (IAA) (27 %) and protein contents (20 %) particularly for those plants inoculated with Sp7 and Sp7-S. Furthermore, Azospirillum inoculation brought no significant disturbance to the composition of indigenous bacterial communities present in the root rhizosphere of the seedlings and aquaponics-grown basil. Thus, this plant growth-promoting rhizobacteria (PGPR) could be an important resource in aquaponics farming to further enhance plant growth and more importantly to increase crop productivity.
Zhu, J., Tremblay, N. and Liang, Y. 2012. Comparing SPAD and atLEAF values for chlorophyll assessment in crop species. Can. J. Soil Sci. 92: 645-648. This research had the objective of determining whether a new light transmittance meter, the atLEAF, could be used as a less expensive alternative to the SPAD meter. Both meters measure transmittance through leaf surfaces in wavelengths associated with chlorophyll, and both provide an indirect method for determining the nitrogen status of crop canopies. The current study compared SPAD and atLEAF values under different conditions and for six crop species (canola, wheat, barley, potato and corn). The results indicated strong correlations among laboratory leaf chlorophyll (Chl) content, SPAD values, and atLEAF values. Equivalent performances were observed for SPAD and atLEAF values in different environments regardless of crop species. Therefore, the atLEAF Chl meter can be used as an inexpensive alternative to the SPAD-502 meter.
Aquaponics, the symbiotic integration of aquaculture and hydroponics, has been touted as a sustainable food production technology. While there is anecdotal evidence, there are only a few studies on the economics of commercial aquaponics. In this study, we collect economic and production information from three aquaponic farms to investigate the economic feasibility of an aquaponics industry in Hawaii. Based on the information supplied by the farms, we develop a model case to analyze (i) profitability, (ii) return on investment, and (iii) input requirements for small-scale commercial aquaponics operation in Hawaii. We find that small-scale commercial aquaponics is economically feasible, but our findings are not as optimistic as those previously published. The modified internal rate of return of the model farm is 7.36%. We conduct sensitivity and decision reversal analysis to investigate how output prices and operational cost parameters affect the overall economic outcome. We find that economic outcome is very sensitive to output price. Investment in commercial aquaponics cannot be supported if annual sales revenue falls by 11%. We conclude by discussing challenges and risks faced by commercial aquaponic farms and the potential economic gain from organic certification and renewable energy implementation.
Aims
Nitrous oxide (N2O) is a strong greenhouse effective gas (GHG); the primary human source of N2O is agricultural activities. Excessive nitrogen (N) fertilization of agricultural land is now widely recognized as a major contributor. In soil, the microbial processes of nitrification and denitrification are the principal sources of N2O. However, it remains poorly understood how conventional hydroponics influences GHG emission. Here, we compared GHG fluxes from soil and rockwool used for hydroponics under identical nutrient conditions.
Methods
Tomato plants (Solanum lycopersicum, momotaro) were grown in soil or by hydroponics using rockwool. In situ emissions of CH4, CO2, and N2O, and the abundance of genes involved in nitrification and denitrification were measured during cultivation.
Results
Hydroponics with rockwool mitigated CO2 emission by decreasing the microbial quantity in the rhizosphere. Dilution of the nutrient solution significantly decreased N2O emission from rockwool. Although proliferation of nitrifiers or denitrifiers in the rhizosphere did not induce N2O emission, reuse or long-term use of rockwool induced a 3.8-fold increase in N2O emission.
Conclusions
Our data suggest that hydroponics has a lower environmental impact and that adequate fertilizer application, rather than bacterial control, governs N2O fluxes in hydroponic cultivation using rockwool.
Urban agriculture, though often difficult to define, is an emerging sector of local food economies in the United States. Although urban and agricultural landscapes are often integrated in countries around the world, the establishment of mid- to large-scale food production in the U.S. urban ecosystem is a relatively new development. Many of the urban agricultural projects in the United States have emerged from social movements and nonprofit organizations focused on urban renewal, education, job training, community development, and sustainability initiatives. Although these social initiatives have traction, critical knowledge gaps exist regarding the science of food production in urban ecosystems. Developing a science-based approach to urban agriculture is essential to the economic and environmental sustainability of the movement. This paper reviews abiotic environmental factors influencing urban cropping systems, including soil contamination and remediation; atmospheric pollutants and altered climatic conditions; and water management, sources, and safety. This review paper seeks to characterize the limited state of the science on urban agricultural systems and identify future research questions most relevant to urban farmers, land-use planners, and environmental consultants.
This chapter is devoted to model checking procedures. Without having validated the assumptions underlying a nonlinear regression model, we cannot be sure that the model is appropriate and consequently that the conclusions based upon the model fit are correct. The kinship to linear regression is apparent, as many of the techniques applicable for linear regression are also useful for nonlinear regression. If any model violations are found, then Chapter 6 should be consulted.
An aquaponic system was designed to investigate effects of foliar applications of some micro- and macro-nutrients on tomato growth and yield in comparison with a hydroponic system. Common carp, grass carp and silver carp were stocked in the rearing tanks at 15, 20 and 15 fish m-3, respectively. The fish were fed three times daily with a pellet diet containing 46% protein. Fourteen days old tomatoes seedlings were transplanted on to growth bed units of aquaponic and hydroponic systems after stocking of carp fish for 2.5 months in the rearing tanks. Foliar nutrients application began 30 days after transplantation. Eight treatments were used, untreated control, foliar application at the rate of 250 ml plant-1 with 0.5 g L-1 K2SO4, MgSO4.7H2O, Fe-EDDHA, MnSO4.H2O, H3BO3, ZnCl2, and CuSO4.5H2O. Plants were sprayed twice a month. The results showed that biomass gains of tomatoes were higher in hydroponics as compared to aquaponics. Foliar application of K, Mg, Fe, Mn, and B increased vegetative growth of plants in the aquaponics. In the hydroponics, only Fe and B had positive effects on plant growth. Cluster number per plant in aquaponics was lower than in hydroponics treatments, but it increased with foliar application of elements. There was no difference in fruit number and yield between aquaponics and hydroponics grown plants in the control treatments. Except Cu, foliar spray of all elements significantly increased plant fruit number and yield in the aquaponics in order of: K>Fe>Mn>Zn>Mg>B. In the hydroponics, foliar application of K, Mg and Zn increased fruit number and yield of plants compared to control. These results indicated that foliar application of some elements can effectively alleviate nutrient deficiencies in tomatoes grown on aquaponics.
Green-leaved foliage plants are valued for their leaf forms and sizes but mainly for their foliar greenness. Evaluation of the quality of these plants has been based primarily on visual grading, which often brings biases, depending on the appraisers. The objective of this study was to evaluate the possibility of using the SPAD-502 as an instrument for estimating plant quality. Ten green-leaved foliage plant species were grown in shaded greenhouses and treated with either a water-soluble fertilizer or a controlled-release fertilizer, each at four nitrogen (N) rates. Six months later, mature leaf thickness was measured and visual quality graded. After the greenness of the mature leaves was measured with the SPAD-502 meter, leaf chlorophyll was extracted using dimethyl sulphoxide, and chlorophyll content was determined. Results showed that leaf thickness ranged from 0.19–0.66 mm among the 10 species but had no apparent effect on either SPAD readings or chlorophyll content. Visual-quality grades of the plants were closely correlated with the SPAD readings (r ≥ 0.84). Highly significant linear relationships (r ≥ 0.87) were found between SPAD readings and chlorophyll a, b, or total chlorophyll content. Thus, the SPAD-502 could be used as an instrument to provide quick, nondestructive, and objective estimation of quality for green-leaved foliage plants.
1. Plant growth is a fundamental ecological process, integrating across scales from physiology to com- munity dynamics and ecosystem properties. Recent improvements in plant growth modeling have al- lowed deeper understanding and more accurate predictions for a wide range of ecological issues, includ- ing competition among plants, plant-herbivore interactions and ecosystem functioning.
2. One challenge in modeling plant growth is that, for a variety of reasons, relative growth rate (RGR) almost universally decreases with increasing size, though traditional calculations assume that RGR is constant. Nonlinear growth models are flexible enough to account for varying growth rates.
3. We demonstrate a variety of nonlinear models that are appropriate for modeling plant growth and, for each, show how to calculate function-derived growth rates, which allow unbiased comparisons among species at a common time or size. We show how to propagate uncertainty in estimated parameters to ex- press uncertainty in growth rates. Fitting nonlinear models can be challenging, so we present extensive worked examples and practical recommendations, all implemented in R.
4. The use of nonlinear models coupled with function-derived growth rates can facilitate the testing of novel hypotheses in population and community ecology. For example, the use of such techniques has allowed better understanding of the components of RGR, the costs of rapid growth, and the linkage be- tween host and parasite growth rates. We hope this contribution will demystify nonlinear modeling and persuade more ecologists to use these techniques.
Aquaponics combines the hydroponic production of plants and the aquaculture production of fish into a sustainable agriculture system that uses natural biological cycles to supply nitrogen and minimizes the use of nonrenewable resources, thus providing economic benefits that can increase over time. Several production systems and media exist for producing hydroponic crops (bench bed, nutrient film technique, floating raft, rockwool, perlite, and pine bark). Critical management requirements (water quality maintenance and biofilter nitrification) for aquaculture need to be integrated with the hydroponics to successfully manage intensive aquaponic systems. These systems will be discussed with emphasis on improving sustainability through management and integration of the living components [plants and nitrifying bacteria (Nitrosomonas spp. and Nitrobacter spp.)] and the biofilter system. Sustainable opportunities include biological nitrogen production rates of 80 to 90 g·m-3 per day nitrate nitrogen from trickling biofilters and plant uptake of aquaculture wastewater. This uptake results in improved water and nutrient use efficiency and conservation. Challenges to sustainability center around balancing the aquaponic system environment for the optimum growth of three organisms, maximizing production outputs and minimizing effluent discharges to the environment.
Four experiments were conducted from 1992 to 1994 to determine the concentrations of N and P required to maximize yields of rockwool-grown cucumbers (Cucumis sativus 'Vetomil') trained with a double-stem method. Concentrations of N and P in rockwool slabs were monitored throughout growth of greenhouse-grown cucumbers. The onset and duration of nutrient depletion in the slabs were related to cucumber yield. In Expt. 1, treatment-1 plants received a two-step solution containing N at 90 and 175 mg·L-1 during successive growth phases, while treatment-2 and -3 plants were grown with N at a constant 175 or 225 mg·L-1. Phosphorus was provided at 50 mg·L-1 in all treatments. Treatment 1 was excluded from Expt. 2. In Expts. 3 and 4, plants were grown with N at 225 or 275 mg·L-1 and P at 75 mg·L-1 Onset of N and P depletion (to < 10 mg·L -1) in the growing slabs occurred during the early fruiting stage of cucumber, 1 to 8 days before first harvest. The duration of N and P depletion decreased, and cucumber yields increased with increasing N and P concentrations. When plants were grown with N and P at 275 and 75 mg·L-1, respectively, N was depleted in the growing slabs during only one experiment and then for only 4 days, and slab P concentration remained >10 mg·L-1. Therefore, under Florida conditions, when growing cucumbers in rockwool using a double-stem training techniques, N and P should be provided at 275 and 75 mg·L-1, respectively, to minimize depletion of these nutrients from the growing medium.
Legume cover crops are often used to build soil nitrogen (N) fertility and there is increasing interest in cover crop mixtures. The objective of this mechanistic greenhouse study was to determine the effect of cover crop community diversity and soil fertility on nitrogenase activity and nodule biomass of cowpea. Cover crops were grown for 42-53 days, aboveground biomass was harvested, and nitrogenase activity was estimated with the acetylene reduction assay. Roots were then excavated to determine nodule and root biomass. Nitrogenase activity and nodule biomass per plant were greatest in cowpea monoculture and reduced by 71-98 percent in four-species mixtures. Reduced capacity for N2-fixation was partially driven by lower cowpea biomass in mixtures. The ratio of root nodule: shoot biomass increased by 81-297 percent in low- relative to high-fertility soils, which contributed to increased nitrogenase activity. Results suggest cowpea monocultures in low fertility soils have the greatest potential for N2-fixation.
Nitrogen transformations in aquaponics with different edible plant species, i.e., tomato (Lycopersicon esculentum) and pak choi (Brassica campestris L. subsp. chinensis) were systematically examined and compared. Results showed that nitrogen utilization efficiencies (NUE) of tomato- and pak choi-based aquaponic systems were 41.3% and 34.4%, respectively. The abundance of nitrifying bacteria in tomato-based aquaponics was 4.2-folds higher than that in pak choi-based aquaponics, primarily due to its higher root surface area. In addition, tomato-based aquaponics had better water quality than that of pak choi-based aquaponics. About 1.5% to 1.9% of nitrogen input were emitted to atmosphere as nitrous oxide (N2O) in tomato- and pak choi-based aquaponic systems, respectively, suggesting that aquaponics is a potential anthropogenic source of N2O emission. Overall, this is the first intensive study that examined the role plant species played in aquaponics, which could provide new strategy in designing and operating an aquaponic system.
Aquaponics is a vegetable production system that integrates soilless cultivation and aquaculture. Plants strip nutrients from fish waste water and convert metabolites toxic to fish. Aquaponics is an environmental-friendly production system due to its full reuse of waste and nutrients. The research, carried out at the Experimental Farm of the University of Tuscia, compared summer yields of two romaine lettuce crops (Lactuca sativa L. 'Integral') grown on aquaponic and hydroponic floating systems. For the hydroponic treatment a nutritive solution of 1.7 dS m-1 and pH 5.5 supported plant growth. For the aquaponic system two treatments under different fish densities supplied nutrients at different concentrations. Every aquaponic treatment consisted of 3 independent 250-L tanks stocked with Nile tilapia (Oreochromis niloticus L.). Each fish tank fed a 1.5 m2 floating system under a 20 plant m-2 density. For the first crop 110 g and 24 g tilapia were stocked at system setup respectively under a low (5 kg m-3) and high (8 kg m-3) density and supplied nutrients with an electrical conductivity (EC) of 0.4 and 0.6 dS m-1. For the second crop 168 g and 90 g tilapia respectively stocked under a low (6 kg m-3) and high (20 kg m-3) stocking density raised EC levels to 0.5 and 1.0 dS m-1. Production of 2.8 kg m -2 from the first hydroponic crop was similar to the 2.7 kg m -2 assessed in the high density aquaponic treatment. Conversely the 2.3 kg m-2 measured in the low density treatment was smaller. For the second trial no differences were noticed between the 6.0 kg m-2 measured in the hydroponic system and the 5.7 and 5.6 kg m-2 assessed in the high and low-density aquaponic treatments, respectively. Nevertheless different nutrient concentrations in water affected plant mineral composition. Aquaponic leaves were poorer in phosphorus but richer in calcium, potassium magnesium and sodium.
An aquaponic system was built, based on the University of Virgin Islands design, as a prototype for commercialization in Alberta, Canada in 2002. It consists of four fish rearing tanks (5 m-3 each) and four raft hydroponic troughs (29 m-2 each). To test commercial feasibility of aquaponics under the climatic conditions of Alberta the food fish tilapia was selected in combination with several conventional greenhouse plants (cucumber, tomato, etc.), herbs, medicinal plants, and nutraceutical plants. A protocol was developed for producing aquaponic crops in Alberta. More than 60 different crops and varieties were tested in a greenhouse. Based on this preliminary evaluation, 24 crops (five greenhouse vegetables and 19 herbs) were grown in trials to determine production levels. Yields of tomatoes and mini-cucumbers reached 20.7 kg plant-1 year-1 and 33.4 kg plant -1 yearc and exceeded average values of commercial greenhouses in Alberta that employ conventional hydroponic technology. During the 2-year study, the yield of Genovese basil increased from 13 kg m-2 year -1 to 42 kg m-2 year-1 as production and harvesting methods were refined. This study demonstrated the technical feasibility of the aquaponic technology in Alberta. Evaluation of the economic feasibility is under way.
Photosynthetic rate of soybeans (on a leaf area basis, PA) estimated from the incorporation of ¹⁴CO2 under field conditions was highly correlated with chlorophyll content of the side leaflets of the same leaves. Among a collection of 48 cultivars, the linear regression of PA on chlorophyll content accounted for 44% of the variation, whereas with a selection of genotypes with various mutant chlorophyll genes, the regression accounted for 81%. When the data for the two tests were re-calculated relative to the check cv. Altona, a quadratic equation between PA and chlorophyll accounted for nearly 90% of the variation. When photosynthetic rate was expressed on a unit chlorophyll basis (Pc), no significant differences among lines were established in the cultivar test. In the mutants test, significant differences in Pc were established with higher values of Pc associated with lower chlorophyll contents; a linear regression accounted for 45% of the variation. Transformation of the data from both experiments relative to Altona allowed the fitting of a common regression line (quadratic) which accounted for 63% of the variation. We suggest that initial screening of progenies in a breeding program for high photosynthetic rate could be done by measuring chlorophyll content.
Portable chlorophyll meters have been reported to provide a new tool to rapidly assess the nitrogen (N) status of growing crops, but need further validation. This study was conducted on growers’ fields to determine if the portable chlorophyll meter is an accurate tool to monitor the N status of irrigated corn (Zea mays L.), thereby allowing producers to make in‐season N application decisions. Results indicate that the chlorophyll meter can be used to separate N responsive from non‐responsive treatments, but it is sensitive to differences in corn hybrid. Chlorophyll meter readings at the 6‐leaf (V6) growth stage were not correlated with final grain yield. However, meter readings at the tasseling (VT) growth stage were predictive of grain yield response at seven of eight research sites. Optimal reading times for in‐season N management were at the V10 and VT stages. Variability in leaf greenness requires a careful sampling technique and a sample size of approximately 30 leaves per field to accurately determine N response. The portable chlorophyll meter can be used to diagnose N sufficiency in irrigated corn, but soil tests are needed to determine the actual amount of N required. Our results indicated that when chlorophyll meter readings are less than 95% of a well‐fertilized reference strip within the same field, additional fertilizer N is warranted.
The influence of nutrient solution adjustment and replacement (management), its electrical conductivity (EC) and plant spacing on yield and quality of strawbeny fruit (var. Torrey) produced in a recirculating hydroponic system was studied at Gosford, New South Wales. Four ways of managing the nutrient solution were examined: (i) pH and EC adjusted daily and the solution replaced every 8 weeks (current grower practice); (ii) as above except that a topping up solution with lower potassium to nitrogen (K: N) ratio was used for EC adjustment; (iii) no daily adjustment of EC or pH and one-third of solution replaced every 2 weeks; and (iv) no daily adjustment of solution volume, EC or pH and full replacement after 8 weeks. Compared with grower practice, these alternative solution management strategies provided no advantage in yield, fruit number, or in the ¦Brix, citric acid, sweetness or flavour of fruit. Use of a topping up solution supplemented with ammonium nitrate (NH4NO3) and calcium nitrate [Ca(NO3)2] to reduce the K : N ratio from 1.7:1.0 to 1.4:1.0 had no effect (P>0.05) on yield but significantly increased (P<0.05) berry weight and improved fruit aroma. Regardless of which method of nutrient solution adjustment and replacement was used, the chemical composition of the recirculating solution changed markedly over 53 days. The method of nutrient solution management significantly (P<0.05) affected leaf phosphorus (P), calcium (Ca), magnesium (Mg), manganese (Mn), and zinc (Zn) but only Mg fell to a suboptimal level for growth of strawberries. Reducing the EC of the nutrient solution from 3 to 2 dS/m at early fruit set gave heavier (P<0.05) berries compared with constant EC of 2 dS/m. Increasing the EC from 2 to 3 or reducing it from 3 to 2 at early fruit set resulted in sweeter (P<0.05) berries and reducing the EC from 4 to 2 improved fruit aroma. Yield declined (P<0.05) when EC was increased from 2 to 4 dS/m. Solution EC bad significant effects (P<0.05) on leaf P, Mg, Mn and Zn. An increase in planting density from 5.35 to 9.35 plants/m2 lowered (P<0.05) marketable yield per plant and fruit acidity but gave 41% higher (P<0.05) yield on an area basis.
Murray Cod, Maccullochella peelii peelii (Mitchell), and Green Oak lettuce, Lactuca sativa, were used to test for differences between three hydroponic subsystems, Gravel Bed, Floating Raft and Nutrient Film Technique (NFT), in a freshwater Aquaponic test system, where plant nutrients were supplied from fish wastes while plants stripped nutrients from the waste water before it was returned to the fish. The Murray Cod had FCR's and biomass gains that were statistically identical in all systems. Lettuce yields were good, and in terms of biomass gain and yield, followed the relationship Gravel bed > Floating > NFT, with significant differences seen between all treatments. The NFT treatment was significantly less efficient than the other two treatments in terms of nitrate removal (20% less efficient), whilst no significant difference was seen between any test treatments in terms of phosphate removal. In terms of dissolved oxygen, water replacement and conductivity, no significant differences were observed between any test treatments. Overall, results suggest that NFT hydroponic sub-systems are less efficient at both removing nutrients from fish culture water and producing plant biomass or yield than Gravel bed or Floating hydroponic sub-systems in an Aquaponic context. Aquaponic system designers need to take these differences into account when designing hydroponic components within aquaponic systems.
In this study volatile and non-volatile compounds, as well as some breeding parameters, were measured in mature fruits of elite sweet pepper (Capsicum annuum) lines and hybrids from a commercial breeding program, several cultivated genotypes and one gene bank accession. In addition, all genotypes were evaluated for taste by a trained descriptive sensory expert panel. Metabolic contrasts between genotypes were caused by clusters of volatile and non-volatile compounds, which could be related to metabolic pathways and common biochemical precursors. Clusters of phenolic derivatives, higher alkanes, sesquiterpenes and lipid derived volatiles formed the major determinants of the genotypic differences. Flavour was described with the use of 14 taste attributes, of which the texture related attributes and the sweet–sour contrast were the most discriminatory factors. The attributes juiciness, toughness, crunchiness, stickiness, sweetness, aroma, sourness and fruity/apple taste could be significantly predicted with combined volatile and non-volatile data. Fructose and (E)-2-hexen-1-ol were highly correlated with aroma, fruity/apple taste and sweetness. New relations were found for fruity/apple taste and sweetness with the compounds p-menth-1-en-9-al, (E)-β-ocimene, (Z)-2-penten-1-ol and (E)-geranylacetone. Based on the overall biochemical and sensory results, the perspectives for flavour improvement by breeding are discussed.
Rice plants were grown in solution culture for a period of five weeks at pH's ranging from 3.5 to 8.5. Maximum dry matter was obtained at pH 5.5, but substantial reductions in the growth of tops and roots were observed at pH's of 3.5 and 8.5. At pH 3.5, both leaves and roots were short and unhealthy. The roots were thickened with lateral root growth severely inhibited. At pH 8.5, the youngest leaves developed chlorotic symptoms with roots being coarse and discoloured.Plant concentrations of essential elements were adequate for normal plant growth at pH 5.5. Iron concentration in plant tops substantially decreased with increase in solution pH, but a reverse trend was observed for roots. The concentrations of other elements progressively increased in plant tops and roots with increasing pH.
BACKGROUND: There is growing interest among consumers in baby leaf vegetables, mostly requested for mixed salads, both as fresh market products and ready-to-use vegetables. Fertilisation is one of the most practical and effective ways of controlling and improving the yield and nutritional quality of crops for human consumption. The optimal fertiliser concentration for baby leaf vegetables depends on the environmental conditions. The aim of the present work was to determine the effects of nutrient solution concentration (2, 18, 34, 50 or 66 mequiv L−1) during two consecutive growing seasons (spring and summer) on the yield and leaf quality of Lactuca sativa L. var. acephala grown in a floating system.
RESULTS: Marketable fresh yield, total dry biomass, leaf area index, macroelement (N, P, K and Mg) concentrations and nitrate and total chlorophyll contents increased in response to an increase in nutrient solution concentration, while the opposite trend was observed for root/shoot ratio and glucose, fructose, starch, total carbohydrate and protein contents. Plants grown in the spring season exhibited lower yield and growth (total dry biomass and leaf area index) but higher leaf quality (higher carbohydrate content and lower nitrate content) than those grown in the summer season.
CONCLUSION: The use of nutrient solution concentrations of 37 and 44 mequiv L−1 for the spring and summer seasons respectively could be adopted in the present conditions to improve marketable fresh yield and leaf mineral content, but with a slight reduction in some nutritional parameters. Copyright
Zucchini plants (Cucurbita pepo L.) were grown in closed soilless systems to analyze the effects of two of the most promising and used irrigation systems (drip and subirrigation) and two cropping seasons (spring-summer and summer-fall) in terms of substrate EC, growth, yield, fruit quality (dry matter, carbohydrates, protein, Vitamin C, nitrates and mineral composition), total nutrient uptake, mineral solution composition and water use efficiency (WUE). Plants grown with subirrigation had a high electrical conductivity in the upper and lower layers of the pots in both growing seasons, especially in the spring-summer season. In the spring-summer season, zucchini yield (total and marketable) was 18% lower with the subirrigation than with the drip-irrigation system, but the fruit quality was higher (dry matter, glucose and fructose concentrations), while no significant difference of total and marketable yield were recorded between irrigation systems during summer-fall season. In both growing seasons, and after 76 days of solution recycling, the variation of nutrients (N, P, K, Mg and Na) in the solution composition at the end of the experiment was lower with the subirrigation than with the drip-irrigation systems. Compared with the spring-summer season, plants grown in the summer-fall season exhibited a 35 and 33% lower total and marketable yield, respectively, but offer several benefits: earlier production (10 days), and higher fruit quality (higher concentration of glucose, fructose, sucrose, starch, P, K, and Mg), and water use efficiency. To produce 1 kg of marketable fruits 29 L of nutrient solution were necessary in the summer-fall season and 42 L in the spring-summer season. From an environmental point of view, growing zucchini during the summer-fall season represents an important practice to improve WUE especially in areas where water conservation is a concern.
This chapter describes the possibility to combine wastewater treatment in recirculating aquaculture systems (RAS) with the production of crop plants biomass. In an aquaponic RAS established in Waedenswil, Zurich, the potential of three crop plants was assessed to recycle nutrients from fish wastewater. A special design of trickling filters was used to provide nitrification of fish wastewater: Light-expanded clay aggregate (LECA) was filled in a layer of 30 cm in vegetable boxes, providing both surface for biofilm growth and cultivation area for crop plants. Aubergine, tomato and cucumber cultures were established in the LECA filter and nutrient removal rates calculated during 42–105 days. The highest nutrient removal rates by fruit harvest were achieved during tomato culture: over a period of >3 months, fruit production removed 0.52, 0.11 and 0.8 gm−2d−1 for N, P and K in hydroponic and 0.43, 0.07 and 0.4 gm−2d−1 for N, P and K in aquaponic. In aquaponic, 69% of nitrogen removal by the overall system could thus be converted into edible fruits. Plant yield in aquaponic was similar to conventional hydroponic production systems. The experiments showed that nutrient recycling is not a luxury reserved for rural areas with litlle space limitation; instead, the additionally occupied surface generates income by producing marketable goods. By converting nutrients into biomass, treating wastewater could become a profitable business.
Linear Mixed-Effects * Theory and Computational Methods for LME Models * Structure of Grouped Data * Fitting LME Models * Extending the Basic LME Model * Nonlinear Mixed-Effects * Theory and Computational Methods for NLME Models * Fitting NLME Models
Tomato fruits ripened 95, 65, 46 and 42 d after flower opening when plants were grown under controlled environmental conditions
at 14, 18, 22 and 26 °C, respectively. A similar response to temperature was observed when the temperature of individual trusses
was modified while the plants were grown at 20 °C. These data were used to develop a thermal time model for fruit maturation.
However, when buds/fruits were heated at different stages in their development, the thermal time model proved to be a poor
predictor of the time of ripening. Fruits were more sensitive to elevated temperature in their later stages of maturation.
Temperature also affected the rates of fruit growth in volume; these could be adequately described using a Gompertz function.
Low temperatures reduced absolute volume growth rates and delayed the time at which the absolute growth rate became maximal.
However, the response of fruit growth to temperature differed when only the temperature of the fruits was modified. There
was a tendency towards small parthenocarpic fruits at both high (26 °C) and low (14 °C) temperature regimes which, combined
with low flower numbers and poor fruit set at 26 °C, resulted in low fruit yields. Temperature also affected the shoot dry
matter content and partitioning. Copyright 2001 Annals of Botany Company
A comparison of three different hydroponic sub-systems (gravel bed, floating and nutrient film technique) in an aquaponic test system
- W A Lennard
- B V Leonard
Lennard, W.A., Leonard, B.V., 2006. A comparison of three different hydroponic
sub-systems (gravel bed, floating and nutrient film technique) in an aquaponic
test system. Aquac. Int. 14, 539-550.
How to fit nonlinear plant growth models and calculate growth rates: an update for ecologists
- C E T Paine
- T R Marthews
- D R Vogt
- D Purves
- M Rees
- A Hector
- L A Turnbull
Paine, C.E.T., Marthews, T.R., Vogt, D.R., Purves, D., Rees, M., Hector, A., Turnbull,
L.A., 2012. How to fit nonlinear plant growth models and calculate growth
rates: an update for ecologists. Methods Ecol. Evol. 3, 245-256.