Evaluation of rainfall interception models in a maize field
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Date
1996
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
Rainfall interception is a component of effective rainfall
and is an important component in agriculture because of the
latter's use in irrigation and drainage projects. A rainfall
interception study was carried out at Kabanana farm plot no.
2952 M, a peri urban area in Lusaka, Zambia. The objectives
of the study were (a) to measure rainfall interception by
maize crop growing in a freely drained soil and (b)
to evaluate and validate the models developed to
represent rainfall interception loss.
Standard raingauges placed adjacent to the study area and
beneath the canopy of the maize plant were used to measure
rainfall amounts. Funnel like collars were used to measure
stemflow. A planimeter was used to measure leaf area required
for the calculation of leaf area index and the data from the
nearby University of Zambia meteorological station was used
to estimate crop evapotranspiration.
The results of the study showed that the interception process
by a maize plant brought about an interception loss of 10%.
Interception loss without stemflow was 27.4% implying that
17.4% of the incident rainfall reached the ground by flowing down the stalk of the maize plant as stemflow.
Of the four models tested the models developed by Merriam
(1960) , Leonard (1965) and De Jong and Cameron (1979) did not
represent the process of interception by a maize plant. The
linear regression model
adopted by Gash
(1979)
which
is
insensitive to canopy structure was 93% significant for a two
sided t-test at 95% confidence interval.
It is highly recommended that the models should be calibrated
before being adopted and a model should be developed that
includes among the usual measurable parameters, leaf area configuration and branching patterns.
Description
Dissertation
Keywords
Maize crop, Kabanana farm, Lusaka- Zambia