Abstract:
Two field experiments were conducted to compare the growth and
yield of tomatoes using experimentation and FAO AquaCrop model at the
University of Cape Coast Teaching and Research Farm in the Cape Coast
Metropolitan Assembly of the Central Region of Ghana. The Randomized
Complete Block Design was used with four (4) treatments and four(4)
replications for the two experiments. The treatments used for both experiments
were T1 – Full irrigation (100 %), T2 – 90 % irrigation, T3 – 80 % irrigation,
T4 – 70 % irrigation. Data was collected on water requirement, plant height,
leaf area, stem diameter, internode length,number of harvested fruits,
fruitsdiameter, weight of harvested fruits and yield for both experiments after
which the results were compared to that generated by AquaCrop model.
At 100 % water application (full irrigation), crop coefficient for tomato
was determined to be 0.62 - 0.63, 1.54 - 1.61, 1.23 - 1.34 and 0.92 –0.93 for
the initial, development, mid-season and the late season stages respectively.
The total amount of water applied for the 116 days ranged between 307 mm
and 359.89 mm. Twenty percent deficit (irrigation) had no significant
reduction on the yield of tomatoes. T4 had adverse effect on the plant and yield
as indicated, which recorded the lowest yield of 3.11 t/ha in the first
experiment and 2.10 t/ha in the second experiment. The model did not
accurately simulate the yield of tomatoes under deficit irrigation. In the case of
T4, however, the level of accuracy was high at 18.09 %. The model was able to
simulate the seasonal ETc for T₂ at 9.88 % in Experiment 1 but not for the
others.
