Theoretical and Experimental Analyses of Nutrient Control in Electrical Conductivity-Based Nutrient Recycling Soilless Culture System

Ahn, Tae In; Shin, Jong Hwa; Son, Jung Eek

doi:10.3389/fpls.2021.656403

Cited by 8 publications

(9 citation statements)

References 57 publications

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“…Although several instances of under- or over-injection were observed, it is considered acceptable for management performance to remain within a 10% margin, given that practical hydroponic ion concentrations may fluctuate by more than 50% ( Ahn et al., 2021 ). Furthermore, the ion-specific nutrient management system can be improved by adopting more accurate ion sensors, pumps, and agitators for mixing the nutrient solution.…”

Section: Discussionmentioning

confidence: 99%

“…However, most soilless cultivation systems replenish the nutrient solution based on the pH and electrical conductivity of the solutions, without considering the varying concentrations of individual ions ( Geoffrey et al., 1997 ; Domingues et al., 2012 ; Katsoulas et al., 2015 ; Kozai et al., 2018 ; Son et al., 2020 ). Furthermore, nutrient uptake rates vary with the growth and development of plants, adding complexity to the management of nutrient composition in recycled nutrient solutions ( Sambo et al., 2019 ; Ahn et al., 2021 ). Consequently, the ion concentrations in the nutrient solution may deviate from the optimal composition, potentially compromising the crop yield and quality.…”

Section: Introductionmentioning

confidence: 99%

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Decision-tree-based ion-specific dosing algorithm for enhancing closed hydroponic efficiency and reducing carbon emissions

Cho,

Gang,

Kim

et al. 2023

Front. Plant Sci.

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The maintenance of ion balance in closed hydroponic solutions is essential to improve the crop quality and recycling efficiency of nutrient solutions. However, the absence of robust ion sensors for key ions such as P and Mg and the coupling of ions in fertilizer salts render it difficult to effectively manage ion-specific nutrient solutions. Although ion-specific dosing algorithms have been established, their effectiveness has been inadequately explored. In this study, a decision-tree-based dosing algorithm was developed to calculate the optimal volumes of individual nutrient stock solutions to be supplied for five major nutrient ions, i.e., NO3, K, Ca, P, and Mg, based on the concentrations of NO3, K, and Ca and remaining volume of the recycled nutrient solution. In the performance assessment based on five nutrient solution samples encompassing the typical concentration ranges for leafy vegetable cultivation, the ion-selective electrode array demonstrated feasible accuracies, with root mean square errors of 29.5, 10.1, and 6.1 mg·L-1 for NO3, K, and Ca, respectively. In a five-step replenishment test involving varying target concentrations and nutrient solution volumes, the system formulated nutrient solutions according to the specified targets, exhibiting average relative errors of 10.6 ± 8.0%, 7.9 ± 2.1%, 8.0 ± 11.0%, and 4.2 ± 3.7% for the Ca, K, and NO3 concentrations and volume of the nutrient solution, respectively. Furthermore, the decision tree method helped reduce the total fertilizer injections and carbon emissions by 12.8% and 20.6% in the stepwise test, respectively. The findings demonstrate that the decision-tree-based dosing algorithm not only enables more efficient reuse of nutrient solution compared to the existing simplex method but also confirms the potential for reducing carbon emissions, indicating the possibility of sustainable agricultural development.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Decision-tree-based ion-specific dosing algorithm for enhancing closed hydroponic efficiency and reducing carbon emissions

Cho,

Gang,

Kim

et al. 2023

Front. Plant Sci.

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“…As such, nutrient monitoring techniques have been studied for both soil and soilless culture systems. A greenhouse experiment assessed soilless culture systems in various system designs, including a closed-loop system applying electrical conductivity sensors (Ahn et al, 2021). Results indicated that succeeding nutrient ratios could be controlled by utilizing a computed nutrient ratio specifically within a closed-loop system setup.…”

Section: Models and Controlsmentioning

confidence: 99%

Closed-Loop Agriculture System Meta-Research Using Text Mining

Zhao

Ragany

Haggag

et al. 2023

Preprint

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A growing global population and climate change threaten the availability of many critical resources, and they are directly impacting the food and agriculture sector. Therefore, new cultivation technologies must be rapidly adopted and implemented to secure the world’s food needs. Closed-loop greenhouse agriculture systems provide an opportunity to decrease resource reliance and increase crop yield. Greenhouses provide versatility in what can be grown and the resources required to function. Greenhouses can become highly efficient and resilient through the application of a closed-loop systems approach that prioritizes repurposing, reusing, and recirculating resources. Here, we employ a text mining approach to research the available research (meta-research) and publications within the area of closed-loop systems in greenhouses. This meta-research provides a clearer definition of the term closed-loop system within the context of greenhouses, as the term was previously vaguely defined. Using the meta-research approach, we identify six major existing research topic areas in closed-loop agriculture systems, which include models and controls, food waste, nutrient systems, growing media, heating and energy. Furthermore, we identify four areas that require further urgent work, which include the establishment of better connection between academic research to industry applications, clearer criteria surrounding growing media selection, critical operational requirements of a closed-loop system, and the functionality and synergy between the many modules that comprise a closed-loop greenhouse system.

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“…▪ The application of electrical conductivity sensors in closedloop soil and soilless growing cultures allows for the predetermination of a plant's future nutrient needs. 1 ▪ Nutrients are most commonly introduced and maintained through water within a greenhouse agriculture system.…”

Section: Growing Conditionsmentioning

confidence: 99%