A Study of the water use of tea in East Africa using a Hydraulic Lysimeter

Abstract

A hydraulic lysimeter, 10 × 10 × 6 ft. deep (3.05 × 3.05 × 1.83 m), has been used to measure the monthly evapotranspiration over a period of 35 months from eight tea bushes planted to be uniform with an extensive area of tea at the Tea Research Institute of East Africa, Kenya. Tests on the performance of this inexpensive lysimeter showed it to be operating satisfactorily and capable of producing valid evapotranspiration data over periods of a few days. The tea was never under serious moisture stress and advection effects were likely to be minimal, with the fetch of the prevailing wind being over 30 km of evergreen moist forest. Monthly evapotranspiration rates (Et.) from the young tea crop varied from 40 to 115 mm per month, but were satisfactorily predicted (r = 0.85), both in wet and dry months, by the relation:....