Application of a modified irrigation method using compensated radiation integral, substrate moisture content, and electrical conductivity for soilless cultures of paprika

Shin, Jong Hwa; Son, Jung Eek

doi:10.1016/j.scienta.2015.11.015

Cited by 23 publications

(25 citation statements)

References 21 publications

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“…In addition, transpiration significantly affects the uptake of nutrients, which is related with the change in root-zone EC and varies with growth stage (Van Noordwijk, 1990; Baille et al, 1994; Le Bot et al, 1998). Therefore, variation of the root-zone EC can be larger depending on growth stage even when the drainage rate is controlled (Massa et al, 2011; Shin and Son, 2016). In the study, the data were acquired in the latter part of the cultivation ( Table 1 ).…”

Section: Discussionmentioning

confidence: 99%

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Forecasting Root-Zone Electrical Conductivity of Nutrient Solutions in Closed-Loop Soilless Cultures via a Recurrent Neural Network Using Environmental and Cultivation Information

2018

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In existing closed-loop soilless cultures, nutrient solutions are controlled by the electrical conductivity (EC) of the solution. However, the EC of nutrient solutions is affected by both growth environments and crop growth, so it is hard to predict the EC of nutrient solution. The objective of this study was to predict the EC of root-zone nutrient solutions in closed-loop soilless cultures using recurrent neural network (RNN). In a test greenhouse with sweet peppers (Capsicum annuum L.), data were measured every 10 s from October 15 to December 31, 2014. Mean values for every hour were analyzed. Validation accuracy (R2) of a single-layer long short-term memory (LSTM) was 0.92 and root-mean-square error (RMSE) was 0.07, which were the best results among the different RNNs. The trained LSTM predicted the substrate EC accurately at all ranges. Test accuracy (R2) was 0.72 and RMSE was 0.08, which were lower than values for the validation. Deep learning algorithms were more accurate when more data were added for training. The addition of other environmental factors or plant growth data would improve model robustness. A trained LSTM can control the nutrient solutions in closed-loop soilless cultures based on predicted future EC. Therefore, the algorithm can make a planned management of nutrient solutions possible, reducing resource waste.

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Section: Discussionmentioning

confidence: 99%

“…These limits result from crops influencing changes in EC and from growth environments (Dewir et al, 2005; Stutte, 2006; Shin and Son, 2016). Because root-zone nutrient solutions are affected by environmental changes within greenhouses, predicting future changes in the EC of root-zone nutrient solutions is not easy.…”

Section: Introductionmentioning

confidence: 99%

Forecasting Root-Zone Electrical Conductivity of Nutrient Solutions in Closed-Loop Soilless Cultures via a Recurrent Neural Network Using Environmental and Cultivation Information

2018

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“…During the day, the rate of transpiration increases due to solar radiation. Daytime irrigation compensates for the transpiration during night and daytime and generates drainage with irrigation exceeding the transpiration rate [11]. Therefore, the water content of the medium decreases during the night, then increases in the daytime due to daytime irrigation, with these repeated saturation patterns measured after reaching field capacity [15].…”

Section: Discussionmentioning

confidence: 99%

“…From these conditions, the difference between the amount of supply and discharge from the root zone can be accurately analyzed using plant nutrient uptake. However, most soilless culture systems are supplied intermittently with nutrients and irrigation water using an automatic control system [11]. In the case of typical soilless culture substrates such as rookwool, a heterogeneous nutrient distribution is formed in the root zone [12].…”

Section: Introductionmentioning

confidence: 99%

Simulation and Experimental Analyses of Nitrate Absorption for Indicator Utilization in Soilless Culture

Ahn¹,

Park²,

Yang³

et al. 2020

Preprint

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Abstract Background: Under intensive fertilization systems such as soilless cultures, a surplus nutrient supply could result in the excessive discharge of fertilizers. However, very few studies have developed nitrate absorption indicators for plants that can be used for decision-making under these systems. This study was conducted to develop indicators related to the absorption of nitrate that can be applied in online systems utilizing the monitored irrigation and drainage amount data, electrical conductivity (EC), and the nutrient analysis data of irrigation and drainage. Results: In the simulation, a stochastic change was generated for the nutrient absorption rate. The theoretical prediction was verified by the cultivation experiment and a higher correlation of tomato yield with the nitrate absorption indicator was confirmed than with the nitrate supply amount. Conclusions: The results of the simulation and cultivation experiments showed that the indicators related to nitrate absorption provide useful information regarding decision-making for efficient resource management through online monitoring.

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“…When the doses of V D , V W , and V S were determined through the abovementioned calculation, a flow rate was generated until the corresponding amount was transferred to V M according to Q drg , Q wtr , and Q stk , respectively. In the simulation, irrigation was controlled by a radiation integral method, which is conventionally used in automated irrigation control [28]. 140 mL of nutrient solution per plant in the mixing tank were supplied whenever the accumulated radiation reached 100 J m −2 .…”

Section: Mixing Of Nutrient Solutionsmentioning

confidence: 99%

Theoretical and Experimental Analysis of Nutrient Variations in Electrical Conductivity-Based Closed-Loop Soilless Culture Systems by Nutrient Replenishment Method

Ahn

Son

2019

Agronomy

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In closed-loop soilless culture systems, variation in nutrients can lead to instability in the nutrient management and forced discharge of nutrients and water. Total nutrients absorbed by plants are replenished in an electrical conductivity-based closed-loop system, and fluctuation in electrical conductivity within a certain range around the initial value can be expected. However, this is not always observed in systems using conventional nutrient-replenishment methods. The objectives of this study were to analyze nutrient variation in a closed-loop soilless culture system based on a theoretical model and derive an alternative nutrient-replenishment method. The performance of the derived alternative method was compared with a conventional nutrient-replenishment method through simulation analysis. A demonstration experiment using sweet peppers was then conducted to confirm whether the theoretical analysis results can be reproduced through actual cultivation. The average amounts of injected nutrients during the experimental period of four months in the conventional and alternative methods were 2257 and 1054 g, respectively. There was no significant difference in the yield of sweet peppers between the two methods. The substrate electrical conductivity in the alternative method was maintained at 2.7 dS·m −1 ± 0.5 within the target electrical conductivity value, while that in the conventional method gradually increased to 5.0 dS·m −1 ± 1.2. In a simulation study, results similar to the demonstration experiment were predicted. Total nutrient concentrations in the alternative method showed fluctuations around the target value but did not continuously deviate from the target value, while those in the conventional method showed a tendency to increase. As a whole, these characteristics of the alternative method can help in minimizing nutrients and water emissions from the cultivation system. Agronomy 2019, 9, 649 2 of 16techniques, unlike open-loop systems. In order to appropriately apply those techniques, theoretical models are required and the problems should be precisely defined [10].In both closed-loop and open-loop soilless culture systems, the electrical conductivity (EC) of the nutrient solution in the mixing tank is adjusted to a target value before the solution is applied to the plant [9,11,12]. However, unlike an open-loop system, the mixing ratio of tap water to stock solution in a closed-loop system is adjusted by considering the change in nutrient concentration due to the inflow of drainage [12]. Alternatively, in simple systems, a premixed standard nutrient solution of a certain EC is supplied based on the difference between initial and current water levels in the circulation tank, which simultaneously performs drainage collection and nutrient-solution feeding [13,14]. In an EC-based closed-loop soilless culture system, supply of stock solution or standard nutrient solution and tap water is intended to replenish nutrients and water consumed in the system [12]. For a single system in which the plants are grown ...

show abstract

Application of a modified irrigation method using compensated radiation integral, substrate moisture content, and electrical conductivity for soilless cultures of paprika

Cited by 23 publications

References 21 publications

Forecasting Root-Zone Electrical Conductivity of Nutrient Solutions in Closed-Loop Soilless Cultures via a Recurrent Neural Network Using Environmental and Cultivation Information

Forecasting Root-Zone Electrical Conductivity of Nutrient Solutions in Closed-Loop Soilless Cultures via a Recurrent Neural Network Using Environmental and Cultivation Information

Simulation and Experimental Analyses of Nitrate Absorption for Indicator Utilization in Soilless Culture

Theoretical and Experimental Analysis of Nutrient Variations in Electrical Conductivity-Based Closed-Loop Soilless Culture Systems by Nutrient Replenishment Method

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