Impact of a Split-Gable Greenhouse Microclimate on the Yield of Irish Potato (Solanum tuberosum L.) Under Tropical Conditions
T. D. Akpenpuun
Department of Agricultural and Biosystems Engineering, University of Ilorin, Nigeria
Y. Mijinyawa
Department of Agricultural and Environmental Engineering,University of Ibadan, Nigeria
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Keywords

Split-gable greenhouse
Controlled environment agriculture
Irish potato
climate
glazing

How to Cite

Akpenpuun, T., & Mijinyawa, Y. (2020). Impact of a Split-Gable Greenhouse Microclimate on the Yield of Irish Potato (Solanum tuberosum L.) Under Tropical Conditions. JOURNAL OF AGRICULTURAL ENGINEERING AND TECHNOLOGY, 25(1), 54-78. Retrieved from http://jaet.com.ng/index.php/Jaet/article/view/150

Abstract

Production of Irish potato is limited to a temperate climate. Increasing demand for this crop has necessitated the introduction of other production options. A possible option is the use of controlled environment agriculture. This study was designed to investigate split-gable greenhouse microclimatic conditions for Irish potato production under tropical conditions. The split-gable greenhouse was developed for tropical conditions and equipped with humidifiers and circulating fan for climate control. Data loggers and a weather station were installed in- and outside the greenhouse to monitor the climate. Five varieties of Irish potato (Nicola, Diamant, Bertita, New seed, Okonkwo) were cultivated in- and outside the greenhouse in two rainy- and dry- seasons. Three seedlings of each variety were planted with 10 replicates using Completely Randomised Design (CRD). The air temperature, Relative Humidity (RH) and Vapour Pressure Deficit (VPD)of the greenhouse were measured in accordance with standard procedures. Yield obtained were compared with standard yield values. Data were subjected to regression analysis and ANOVA at α0.05.Greenhouse floor, wall, roof, glazing, ventilation area and volume were 48.0, 84.0, 52.4, 108.4, 32.8 m2 and 175.4 m3, respectively. The humidifier and fan had capacities 7.4 g of H2O/kg of air.h and 2.5 m3/s air flow rate, respectively. The thickness and light transmittance of the glazing material was 2 mm and 75%, respectively. The pitches, rises and pitch angles of the split-gable roof were 0.3/0.2, 1.6/1.0 m and 15.1o/9.7o, respectively. Rainy season temperature, RH and VPD were 23.6±1.1oC, 82.3±2.8% and 0.5±0.1 kPa, respectively inside the greenhouse compared with 29.3±1.2oC, 78.5±7.3% and 1.2±0.2 kPa outside the greenhouse. Dry season temperature, RH and VPD were 25.5±2.7oC, 75.3±2.4% and 0.7±0.3 kPa, respectively inside the greenhouse compared with 36.1±1.9oC, 63.12±10.4% and 2.2±0.7 kPa, respectively outside the greenhouse. Greenhouse microclimatic conditions were within the reported threshold of 15-35oC, 70-85% and 0.4-1.0 kPa necessary for potato production. Bertita and New seed had the highest yield of 6.4 and 6.1 kgm-2, respectively in rainy season and 5.3 and 5.4 kgm-2, respectively in the dry season inside the greenhouse. New seed gave the highest yield of 1.7 kgm-2 outside the greenhouse both in rainy- and dry- seasons, while Okonkwo had the least 0.2 kgm-2 outside the greenhouse in dry season. Reported equivalent mean yield in au State for the five varieties were in the range 7.6-11.3 kgm-2. Climatic data and yield in- and out- side the greenhouse differed significantly. Temperature, RH and VPD had significant interactions with yield. A split-gable greenhouse that provided suitable microclimatic conditions for Irish potato production in tropical conditions was developed.

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