Full Length Research Paper
Abstract
Efficient crop coefficient (Kc) estimation is very important to adequately determine water use of a selected crop. In this study, crop coefficient was determined for upland rice (NERICA) under a sprinkler irrigation system. The estimation was derived from the relationship
, where LAI is leaf area index and MTA is the mean tilt angle, under standard environmental conditions in Ibadan, Nigeria. The fraction of the wetted surface 
was determined for initial, mid season and maturity growth stages. These were then incorporated into the model flowchart that produced soil water coefficient for evaporation, Ke, basal crop coefficient, Kcb and crop coefficient for evapotranspiration, Kc. Several assumptions were made and a visual basic (VB) 6.0 software was used as programming language. The derived Kc was compared with existing crop coefficients and results were subjected to statistical analysis. The models derived for initial, mid season and maturity growth stages are
,
and -0.1308 + 0.1193LAI - 0.024COSMTA respectively. The model incorporating all growth stages of the form,
. The Kc values for the three growth stages were 0.9 (initial), 1.12 (mid season) and 0.7 (maturity). The coefficient of distribution, R2 between the modeled Kc and those using FAO-24 and FAO-56 guidelines were 0.99 and 0.98 respectively indicating a good agreement with the existing coefficients. The result also supported the improvised conversion factor from Kc (paddy) to Kc (upland) as it is used in FAO-24 paper. The dominant effect of
, LAI and MTA on the crop coefficient of upland rice is evident from the results.
Key words: Crop coefficient, upland rice, sprinkler irrigation.
Copyright © 2024 Author(s) retain the copyright of this article.
This article is published under the terms of the Creative Commons Attribution License 4.0
