Comparisons of Ion Balance, Fruit Yield, Water, and Fertilizer Use Efficiencies in Open and Closed Soilless Culture of Paprika (Capsicum annuum L.)

Ko, Myat Thaint; Ahn, Tae In; Son, Jung Eek

doi:10.7235/hort.2013.13028

Cited by 6 publications

(5 citation statements)

References 16 publications

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“…These results suggest that the interpolation of the ion concentrations was a reasonable approach, and the deviance was due to the nature of the closed-loop condition. One characteristic of a closed-loop condition is frequent variation in ion concentrations toward the latter stages of cultivation [2, 24]. After April, ion concentrations greatly increased before returning to prior levels, but the ion concentrations fluctuated similar to the increasing tendency of the EC (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Closed-loop soilless cultures are constantly being evaluated for sustainable agricultural research. In the closed-loop condition, root-zone is a crucial environment because nutrient solutions are reused and plants uptake ions selectively [34]; therefore, an imbalance of nutrients can occur and result in the accumulation of specific nutrients [24, 33, 39]. Accumulation of specific ions can increase deviations in nutrient solutions, resulting in reduced crop yields.…”

Section: Introductionmentioning

confidence: 99%

“…However, because EC does not show each ion concentration, the ion balance in EC-based control systems cannot be estimated. For example, the nutrient solutions were empirically refreshed with growth stage in an EC-based control system, but the solutions were roughly controlled [24, 25]. To monitor individual ions in real time, several ion-selective electrodes have been introduced, but it require sampling and calibration processes [22].…”

Section: Introductionmentioning

confidence: 99%

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Long short-term memory for a model-free estimation of macronutrient ion concentrations of root-zone in closed-loop soilless cultures

2019

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Background Root-zone environment is considered difficult to analyze, particularly in interpreting interactions between environment and plant. Closed-loop soilless cultures have been introduced to prevent environmental pollution, but difficulties in managing nutrients can cause nutrient imbalances with an adverse effect on crop growth. Recently, deep learning has been used to draw meaningful results from nonlinear data and long short-term memory (LSTM) is showing state-of-the-art results in analyzing time-series data. Therefore the macronutrient ion concentrations affected by accumulated environment conditions can be analyzed using LSTM. Results The trained LSTM can estimate macronutrient ion concentrations in closed-loop soilless cultures using environmental and growth data. The average training accuracy of six macronutrients was R 2 = 0.84 and the test accuracy was R 2 = 0.67 with RMSE = 1.48 meq L −1 . The used values of input interval and time step were 1 h and 168 (1 week), respectively. The accuracy was improved when the input interval became shorter, but not improved when the LSTM consisted of a multilayer structure. Regarding training methods, the LSTM improved the accuracy better than the non-LSTM. The trained LSTM showed relatively adequate accuracies and the interpolated ion concentrations showed variations similar to those seen during traditional cultivation. Conclusions We could analyze the nutrient balance in the closed-loop soilless culture, the model showed potential in estimating the macronutrient ion concentrations using environmental and growth factors measured in greenhouses. Since the LSTM is a powerful and flexible tool used to interpret accumulative changes, it is easily applicable to various plant and cultivation conditions. In the future, this approach can be used to analyze interactions between plant physiology and root-zone environment.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long short-term memory for a model-free estimation of macronutrient ion concentrations of root-zone in closed-loop soilless cultures

2019

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“…In open hydroponics, the nutrient solution flows through the growing bed and is discarded, which can result in the pollution of ground-and surface water [3,4]. In closed hydroponics, which collects drainage solutions and reuses these by replenishing water and nutrients, the use and discharge of water and nutrients are less than for open hydroponics [5][6][7]. Therefore, a transition from open hydroponics to closed hydroponics is seen increasingly often due to the more environmentally-friendly aspect of closed hydroponics [7].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Signal-Processing Method Based on Neural Network for Prediction of NO3, K, Ca, and Mg Ions in Hydroponic Solutions Using an Array of Ion-Selective Electrodes

Cho

Kim

Park

et al. 2019

Sensors

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In closed hydroponics, fast and continuous measurement of individual nutrient concentrations is necessary to improve water-and nutrient-use efficiencies and crop production. Ion-selective electrodes (ISEs) could be one of the most attractive tools for hydroponic applications. However, signal drifts over time and interferences from other ions present in hydroponic solutions make it difficult to use the ISEs in hydroponic solutions. In this study, hybrid signal processing combining a two-point normalization (TPN) method for the effective compensation of the drifts and a back propagation artificial neural network (ANN) algorithm for the interpretation of the interferences was developed. In addition, the ANN-based approach for the prediction of Mg concentration which had no feasible ISE was conducted by interpreting the signals from a sensor array consisting of electrical conductivity (EC) and ion-selective electrodes (NO 3 , K, and Ca). From the application test using 8 samples from real greenhouses, the hybrid method based on a combination of the TPN and ANN methods showed relatively low root mean square errors of 47.2, 13.2, and 18.9 mg·L −1 with coefficients of variation (CVs) below 10% for NO 3 , K, and Ca, respectively, compared to those obtained by separate use of the two methods. Furthermore, the Mg prediction results with a root mean square error (RMSE) of 14.6 mg·L −1 over the range of 10-60 mg·L −1 showed potential as an approximate diagnostic tool to measure Mg in hydroponic solutions. These results demonstrate that the hybrid method can improve the accuracy and feasibility of ISEs in hydroponic applications.

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“…For the adjusting interval of recycled nutrient solutions, Ko et al (2013aKo et al ( , 2013b investigated the growth of paprika under different renewal periods with the constant interval. However, for more practical operation of closed soilless culture systems, extended adjusting intervals are more favorable.…”

Section: Introductionmentioning

confidence: 99%

Effects of Renewal Pattern of Recycled Nutrient Solution on the Ion Balance in Nutrient Solutions and Root Media and the Growth and Ion Uptake of Paprika (Capsicum annuum L.) in Closed Soilless Cultures

Ko¹,

Ahn²,

Shin³

et al. 2014

HST

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Ion imbalance in recycled nutrient solutions is caused by selective ion uptake of plants, which occurs at different rates in different growth stages. The objectives of this study were to investigate the ion balances in both recycled nutrient solutions and rockwool media using different renewal patterns for the nutrient solutions, and to analyze the subsequent effects on uptake of water and nutrients. Over 12 weeks of paprika cultivation, two different renewal patterns (week units) of 6-4-2 and 8-2-2 weeks were compared with a constant renewal pattern of 4-4-4 weeks (control). The nutrient solution in the reservoir tank was constantly maintained at EC 2.5 dS･m -1 and pH 5.5-6.5. The changes in the ion balance with the 4-4-4 week pattern were smaller than those with the other treatments. In the early growth stage, however, the ion balances similarly changed among all treatments. Greater changes were subsequently observed for the 6-4-2 week pattern. Although fruit yield and shoot fresh weight of paprika were the lowest with 6-4-2 renewal pattern, no significant differences were observed. Our results indicate that renewal intervals can be extended in consideration of growth stage for more efficient and practical operations in closed soilless cultures.

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Comparisons of Ion Balance, Fruit Yield, Water, and Fertilizer Use Efficiencies in Open and Closed Soilless Culture of Paprika (Capsicum annuum L.)

Cited by 6 publications

References 16 publications

Long short-term memory for a model-free estimation of macronutrient ion concentrations of root-zone in closed-loop soilless cultures

Long short-term memory for a model-free estimation of macronutrient ion concentrations of root-zone in closed-loop soilless cultures

Hybrid Signal-Processing Method Based on Neural Network for Prediction of NO3, K, Ca, and Mg Ions in Hydroponic Solutions Using an Array of Ion-Selective Electrodes

Effects of Renewal Pattern of Recycled Nutrient Solution on the Ion Balance in Nutrient Solutions and Root Media and the Growth and Ion Uptake of Paprika (Capsicum annuum L.) in Closed Soilless Cultures

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