Evaluation of Reference-Crop Evapotranspiration Models, Crop Evapotranspiration Methods and Water Supply Methods for the Determination of Crop Coefficient of Kenaf

• A.O. Eruola

  Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

  Author

• K.O. Ayoola

  Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

  Author

• J.O. Adejuwon

  Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

  Author

• M.A. Busari

  Department of Soil Science and Land Management, University of Agriculture, Abeokuta, Nigeria

  Author

• A.A. Makinde

  Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

  Author

Field and pot experiment were conducted in University of Agriculture, Abeokuta, to develop crop coefficients (Kc) for kenaf. Efficiency of lysimeters and Time Domain Reflectometery (TDR) in the measurement of Crop evapotranspiration (ETc) and the Cropwat and Instat+ models in estimating reference evapotranspiration (ETo) were evaluated. The experiment involved three varieties of Kenaf (Ifeken 100, Cuba 108 and Tainung 2) and two water supply methods (rain-fed and irrigation). Physiological parameters and Kc estimated during the different phenological stages of kenaf grown were analyzed with respect to treatments using inferential statistics. The result showed that Cropwat and Instat+ were related (P < 0.05) in their estimation of ETo. A strong positive linear relation (R2= 0.72, p < 0.05) was recorded between lysimeters and TDR measured crop evapotranspiration both on the field and in the container experiment irrespective of variety and water supply method. The Kc from this study were highest in mid-season (0.9 - 1.2), followed by crop development period (0.5 - 0.8), then late period (0.3 – 0.7) and finally the initial stage (0.2 - 0.4) for all varieties of crop shown irrespective of water supply methods. The Kc for the total growth period is estimated to ranged between 0.6 - 0.7. The Kc determined by lysimeter were about 10% higher than the TDR during the late mid - period and the late period. The field determined Kc were slightly higher than those in the container grown crop due to container surface area lower than the ground area for planting of crop. The study further confirmed that variety selection of kenaf, water supply method and their interaction does not significantly (p> 0.05) influenced crop coefficient during the trial. It could be concluded that investigating Kc provides a scientific basis for determining the extent to which the water availability will satisfy water requirement of kenaf during the different phenological stages.

1. A.O. Eruola, Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

   Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

2. K.O. Ayoola, Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

   Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

3. J.O. Adejuwon, Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

   Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

4. M.A. Busari, Department of Soil Science and Land Management, University of Agriculture, Abeokuta, Nigeria

   Department of Soil Science and Land Management, University of Agriculture, Abeokuta, Nigeria

5. A.A. Makinde, Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

   Department of Water Resources Management and Agrometeorology, University of Agriculture, Abeokuta, Nigeria

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