DETERMINATION OF CROP COEFFICIENT OF OKRA (Abelmoschus esculentus) UNDER MSU-GSC CONDITION

This study was conducted to determine the average crop coefficient factor of Okra (Abelmoschus esculentus) in every growth stage under MSU-GSC condition. The focus of this study is to determine the crop coefficient at the four different stages of growth of Okra which are the initial, development, flowering and maturity stage. The study was conducted from March 13, 2019 to May 1, 2019 in the net house at the Agricultural and Biosystems Engineering Complex, Mindanao State University — General Santos City. In order to determine the crop evapotranspiration (ETc) and reference crop evapotranspiration (ETo) of Okra, soil water balance and pan evaporation method were used, respectively. Having determined the ETc and ETo, crop coefficient factor, Kc, can be determined. It was observed that the average Kc value of Okra in its initial stage, development stage, flowering stage and maturity stage were 0.84, 0.96, 1.01 and 1.18, respectively. The Kc values less than 1 implies that reference evapotranspiration (ETo) or the evaporation power of the atmosphere during this stage of growth is larger than the actual evapotranspiration (ETc) of the plants. This means that evapotranspiration on the soil surface surrounding the plants is greater than the actual evapotranspiration. On the other hand, Kc values that are greater than 1 implies that ETc is larger compared to the ETo which means that the actual water use of plants is larger compared to the evapotranspiration in the surrounding atmosphere. Kc values during the initial and development growth stage of Okra is reasonably less than 1 since the leaf area is relatively smaller compared to the soil surface exposed in direct sunlight. Meanwhile, the Kc values during the flowering and maturity stage of growth is greater than 1 since the leaf area is relatively larger and shades the soil surface. The average crop coefficient increases gradually with the different stages of growth. The values of Kc can be used as a useful tool for estimating water requirements of Okra. It will also be of big help in developing the irrigation system in urban places and also to the farmers for precision agriculture. The whole experimental set-up of Okra plant takes about 38.31 L or 0.383055 m3 of water for the whole cropping season.