Abstract:
Efficient and good water management strategy requires knowledge of crop water use of which
reference evapotranspiration
(RET) and crop curves are important
inputs. Field experiments
bahama grass (cynodon dactylon) were conducted to estimate consumptive
and four drainage
microlysimeters
microlysimeters.
were installed.
using one weighing
The grass was planted on 12m by 16m plot in which the
The weighing microlysimeter
principles using mercury-in-glass
use
on
manometer.
was construction
Its calibration
based on hydraulic
was carried out using a static load
process.
Ten years of climatic data were used to estimate
following
empirical
methods;
Hargreaves (HG) models.
Penman
(PEN),
reference
Jensen-Haise
evapotranspiration
using the
(J-H) , Blaney-Criddle(B-C)
and
The values obtained were compared to experimental values and were also
subjected to standard statistical analysis.
Crop curves were obtained
from the ratio oflysimeter
to reference evapotranspiration
values
(using empirical formulae). The crop curves were presented as a function of independent variables
which were Days After Planting (DAP) and Thermal Time (T>T). For the crop curves based on DAP,
the coefficient of determinatioruk/)
and standard errors (SE) in the crop coefficients (K) estimates
were 0.90 and 0.17 respectively for the J-H ; 0.90 and 0.09 for PEN; 0.89 and 0.07 for B-C; 0.81 and
018 for HG. Based on TT method, R2 and SE for J-H were 0.90 and 0.18 respectively. 0.90 and 0.09
for PEN; 0.89 and 0.07 for B-C; and 0.81 and 0.18 for HG.
