Evaluation of Evapotranspiration Models for Waterleaf crop using Data from Lysimeter (original) (raw)

Evaluation of Evapotranspiration Models for Waterleaf crop using Data from Lysimeter

Lysimeters are tanks used to measure the amount of water used in evapotranspiration (ET) on a vegetated surface. Lysimeters are the most reliable method to measure direct evapotranspiration from a vegetated area, as long as they are properly installed, operated and well managed. Three lysimeters were standardized and used for this study. Plastic containers of 350 mm in height and 300 mm diameter were filled with sandy-loam soil. A sensitive weighing balance was used to measure the changes in weight during the experiments. Daily evapotranspiration data were collected. An irrigation frequency of 2 times per week of 8 cm depth was applied to prevent permanent wilting. Climatic data were obtained from the weather stations of Sam Mbakwe airport, Imo state and Anambra Imo-River Basin Development Authority (AIRBDA), Owerri, Imo State, Nigeria, for Blaney-Morin Nigeria (BMN), Blaney-Criddle (BC), Hargreaves and Piche atmometer evapotranspiration measurement to compare with ET data from the lysimeters. The evapotranspiration results for the lysimeter, Blaney-Morin Nigeria (BMN), Blaney-Criddle (BC), Hargreaves and Piche atmometer evaporation were 5.03, 5.44, 4.95, 4.86 and 4.78 mm/day respectively. Analyses of the data show that the ETc values for BMN, BC, HG, and Piche compared favourably with the ETc from the Lysimeter. ETc for BMN was slightly higher than the value for the Lysimeter, while the ETc for BC, HG and Piche were slightly lower. Based on this study (lysimeter used and crop studied), it can be concluded that this type of lysimeter is a good method for determining the evapotranspiration of waterleaf crop and other similar crops. Therefore, this simple lysimeter can be used to generate ET data where standard climatic data measurements are not available.