LYSIMETRIC ESTIMATION OF CROP WATER USE FOR COWPEA (Vigna Unguiculata) UNDER RAIN-FED CONDITION IN KANO, NIGERIA
Publication Date : 01/02/2018
Lysimetric estimation of crop Water use of cowpea (vigna unguiculata) under Rainfed condition was carried out using weighing – type micro-lysimeter. The micro-lysimeters were made up of locally available materials and calibrated before the experiment was set up. A glass tube manometer was connected to the weighing system to determine the daily rise and fall of the water. The manometer determines the weight of water that was displaced from the Lysimeter using using water balance equation to determine the crop consumptive use. Daily manometer readings, runoff and drainage water were recorded. Rainguage was installed in the field to measure amount of rainfall during the experimental period. The result of the experiment revealed that the daily evapotranspiration (ETc) of the cowpea variety (vigna unguiculata (L) walp 277) varied from 0.3 mm to 8.5 mm while the weekly ETc varied from 9.9mm to 28.6 mm and the Kc values obtained were 0.72, 0.86, 0.63 and 0.30 for Initial, Developmental, Mid and Late season respectively. However, the annual water consumptive use was found to be 199.5 mm. Therefore, this technique provides easy way of estimating crop water use. The results obtained may be applied to achieve proper scheduling of planting cowpea so as to enable the crop receive adequate rainfall before harvesting.
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