A study was conducted to determine the evapotranspiration (ETC) and deep percolation losses (DP) of a paddy field using micro-lysimeter in peninsula Malaysia. Realistic estimate of evapotranspiration (ET) is a major factor in agricultural planning and determining crop production potential of a given region. Non-weighing Marriott micro-lysimeter was installed in the field to measure ETC and DP. A constant water level was maintained in the micro-lysimeter with a Marriott tube system and water losses from the manometer were measured. Daily variations of ET and deep percolation (DP) were determined in Peninsula Malaysia for mid (April to August) and rainy (August to February) cropping season. The results of the measured mean ETC for mid-season were between 4.42 mm/day to 6.40 mm/day, while DP losses for the season ranged from 2.0 mm/day to 6.54 mm/day. For the rainy season the mean ETC obtained were between 3.62 mm/day and 6.65 mm/day and the DP for the season obtained ranged from 1.64 mm/day to 4.59 mm/day. The descriptive statistics employed to test the distribution of the ETC data for normality revealed that the data were normally distributed. The skewness and kurtosis values obtained were the conventional acceptable limits. The micro-lysimeter can measure ETC with satisfactory results and can be employed by local farmers and irrigation managers for water resources planning and management.

Keywords: Micro-lysimter, evapotranspiration, marriott tube, deep percolation