Estimation of Actual Evapotranspiration and Crop Coefficient of Transplanted Puddled Rice Using a Modified Non-Weighing Paddy Lysimeter

Lysimetric and eddy covariance techniques are commonly used to directly estimate actual crop evapotranspiration (ETa). However, these technologies costly, laborious, require skills which make in situ ET estimation difficult, particularly developing countries. With this mind, an attempt was made determine ETa stagewise coefficient (Kc) values of transplanted puddled rice using a modified non-weighing paddy lysimeter. The results were compared indirect methods, viz., FAO Penman–Monteith pan evaporation. Daily ranged from 1.9 8.2 mmday?1, with mean 4.02 ± 1.35 their comparison showed that the equation performed well for determination (R2 0.63), root squared error (RMSE = 0.80), absolute percentage (MAPE 13.6 %), highly correlated throughout season. evaporation approach underestimated 0.24; RMSE 0.98; MAPE 22.13%) due consistent value (0.71), vegetation role measurement errors. In addition, Kc obtained as 1.13 0.13, 1.27 0.2, 1.23 0.16, 0.93 0.18 initial, development, mid-season, end-season stages, respectively. These estimated higher than values. Statistical analysis revealed overall stagewise-derived average line values, but different derived although found insignificant at 5% significance level. water productivity agro-meteorological indices evaluate cultivar performance experiment. Therefore, such methodology may be absence weighing lysimeter-derived regional can applied improve irrigation scheduling under similar agro-climatic conditions.