1 Plant Archives Vol. 21, Supplement 1, 2021 pp. 781-784 e-ISSN:2581-6063 (online), ISSN:0972-5210 Plant Archives Journal homepage: http://www.plantarchives.org doi link : https://doi.org/10.51470/PLANTARCHIVES.2021.v21.S1.117 EFFECT TRADITIONAL GREENHOUSE (HIGH TUNNEL) IN THE CHARACTERISTICS OF GROWTH AND YIELD OF THE CUCUMBER Mahmood Mejbel Jameel, Montaser Khairie Khessro, and Hussain Jawad AL-Bayati College of Agriculture and Forestry University of Mosul, Nineveh, Iraq. E-mail: mahmoodmejbel32@gmail.com ABSTRACT This study was conducted in greenhouses belongs to the College of Agriculture and Forestry at the University of Mosul, for the autumn season 2019. The research included adding a ventilation system that included air circulation inside the greenhouse to eliminate excessive moisture and heat, as well as uniformity of the internal environment of the greenhouse. The greenhouse was divided according to Randomize Complete Block Design in a factorial experiment. The study has been divided into five ridges; the three intermediate ridges were divided into 6 blocks. A sampling of replications was taken according to the vegetative indicator of the studied yield. The two Greenhouses were planted with the yield of the cucumber. Dimensions of the greenhouse were area of 396m 2, length of 44m, a width of 9m, and a height of 3.45m. The first greenhouse was chosen to be without mechanical ventilation. As for the second greenhouse, ventilation and air circulation system (three exhaust fans and other five fans for air circulation) have been added, which works automatically using a low-cost controller (Arduino). The purpose of adopting the Arduino is to ensure the operation and shutting down the ventilation system through sensors reading according to the need of the crop, thus saving electrical energy. The greenhouse was not warm and the time for planting was late. The readings were taken for the vegetative growth indicator obtained during the growth and production period of the cucumber. From the results collected, it was found that the growth and yield indicator of the cucumber crop gave the best results in the greenhouse with mechanical ventilation in comparison with natural ventilation. The results obtained showed that growth indicator for the greenhouse with mechanical ventilation were better in terms of growth. The difference was significant in the height of the plant, whereby the average length of plants for the automated house was 191.93 cm. As for the traditional greenhouse the length recorded 131.70 cm. the percentage of chlorophyll in the leaves of the plant was 1.6 % higher. The leaf surface area of the plant in the automated house reached 14070 cm 2 . Plant -1 , whereas in the traditional house, recorded 11281 cm 2 .plant -1 . The total crop yield achieved was 126% higher in the greenhouse with mechanical ventilation in comparison with the greenhouse of natural ventilation. Keyword : Greenhouse, air circulation, cucumber, high tunnel, Arduino. Introduction The increase in global demand for food is a result of the increase in population moreover the desire to diversify in vegetable crops. The nature of the climate in the Arab countries sometimes is not suitable for production, which leads to a lack in the local need for vegetables and fruits, hence the protected agriculture is of great importance in filling the shortfall in agricultural production and achieving self-sufficiency around the year (Al-Saadoun and Surur, 2005). Protected agriculture is a specialized agricultural system in which exercises supervising and controlling over the soil environment and mini climate, by adjusting conditions such as soil, temperature, radiation, wind, humidity, and air composition). Whereby plants are grown inside the greenhouses which modify their natural environment to obtain products in the off-season, moreover to prolong their production period. Thus increase yields and improve the quality of agricultural products. Eventually meeting the need for agricultural products that cannot be provided by relying on exposed planting only (Castilla, Wittwere, 1995). Hence the idea of research was adopted, represented in adding a forced ventilation system to the greenhouse environment/mini climate, to get a good condition for the plant growth, provided the lowest rate of energy expenditure. We discussed in our research the cucumber crop that is considered one of the most important crops of vegetables grown in greenhouses. Cucumber also belongs to the Cucurbitaceae family. It is important in many countries of the world, including Iraq. It has a demand in the global and Iraqi markets throughout the months of the year. Accordingly, the crop must be supplied throughout the year by increasing the planted areas and following the correct agricultural methods in planting and serving the crop (Al- Bayati et al., 2012). The cucumber is greatly planted under the farming system (traditional greenhouses) where the number of classic greenhouses increased to (41776) at 2019 in terms of The Iraqi level moreover in the province of Nineveh that reached to (550), according to the report of the vegetable production of crops and vegetables during the year (2019). The inner environment of greenhouses is a collection of climatic conditions that surround living plants, and in turn, are affected by climatic conditions outside the greenhouse in a large way. This greatly affects plant metabolism activities