Development of a real-time irrigation control system considering transpiration, substrate electrical conductivity, and drainage rate of nutrient solutions in soilless culture of paprika (Capsicum annuum L.)

Abstract. In a soilless culture, water and nutrients must be frequently and precisely applied due to the reduced volume and low water holding capacity of the substrate. We describe a low-cost and efficient control system for the irrigation management of soilless culture based on an irrigation tray. Both irrigation and drainage volumes from the irrigation control tray are measured automatically. The proposed irrigation scheduling options were based on applying both variable timing and amounts. A Proportional Integral Derivative (PID) algorithm was used to establish the irrigation timing option while two different irrigation application options, based on measurements from the drainage hydrograph, were developed and tested. A field test performed on a tomato crop was carried out to assess the performance of the two irrigation application options. Both irrigation algorithms performed well as they fitted the leaching fraction for every irrigation event to the target value. The fruit yield and quality were comparable to results obtained from the control treatment of the tomato crop. The designed low-cost irrigation control system, if implemented on commercial farms, could prove to be economically very beneficial. Keywords: Automation, Drainage hydrograph, Irrigation control tray, Irrigation scheduling, Proportional-Integral-Derivative (PID) controller, Substrate culture.

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Effect of irrigation with nutrient solutions mixed with treated wastewater on Asiatic lily ‘Brunello’ grown in a closed soilless culture

Acta agriculturae Slovenica ◽

10.14720/aas.2017.109.1.03 ◽

2017 ◽

Vol 109 (1) ◽

pp. 29

Author(s):

Ahmed Abdel-Nabi Al-Hammouri ◽

Khalid Al-Ghawanmeh ◽

Nabeel Bani Hani ◽

Nabeela Karam

Keyword(s):

Electrical Conductivity ◽

Nutrient Solution ◽

Dry Mass ◽

Treated Wastewater ◽

Soilless Culture ◽

Cut Flowers ◽

High Quality ◽

Greenhouse Study ◽

Potential Use ◽

Nutrient Solutions

A plastic greenhouse study was implemented to evaluate the potential use of treated wastewater for irrigation of Asiatic lily ‘Brunello’ grown in zeolite. Plants received the following treatments: a nutrient solution (N) alone, (N) mixed with treated wastewater (W) at rates of 3N:1W, 1N:1W and 1N:3W respectively. A closed system was used in which the drain solution was circulated for several days until its electrical conductivity reached 2.3 dS m-1, after which fresh irrigation solutions were used to start a second cycle of circulation. The results indicated that plants irrigated with (N) or 3N:1W solution had the longest stems (34.4 and 36.2 cm) respectively, peduncles and buds (about 4.5 cm), and the greatest shoot (3.4 and 3.8 cm) and bud mass (14.95 and 17.6 g) respectively. Plants irrigated with 1N:3W solution had the highest dry mass tissue content of K (3.06 g kg -1) and B (35.5 mg kg-1). Plants irrigated with 1N:1W or 1N:3W were inferior to other plants. It can be concluded that 1N:3W mixture may be used for production of high quality cut flowers of lily. Moreover, it is expected to save 3.4 litres m-2 of a nutrient solution and 1850, 347 and 1870 mg m-2 day-1 for N, P, and K respectively.

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