ABSTRACT
Evaporation Measurements ................................. 30 2.2.3 Evaporation from Bare Soil ............................................... 30 2.2.4 Evaporation Studies Based on Analysis of
Metrological Data ............................................................... 35 2.2.5 Evaporation Modeling ........................................................ 37 2.3 Materials and Methods ................................................................... 41
2.3.1 Experimental Site ............................................................. 41 2.3.1.1 Soil Types .......................................................... 41 2.3.1.1.1 Chemical Properties of Soil ............. 42 2.3.1.1.2 Physical Properties of Soil .............. 43 2.3.2 Experimental Plots ........................................................... 44 2.3.3 Details of Laboratory Simulation Studies ........................ 45 2.3.3.1 Fabrication of Experimental Soil Columns ....... 45 2.3.3.2 Preparation of Soil Columns ............................. 45 2.3.4 Fabrication of Gypsum Blocks ......................................... 47 2.3.5 Tensiometers ..................................................................... 47 2.3.6 Tube Auger ....................................................................... 48 2.3.7 Climatic Parameters ......................................................... 48 2.3.8 Observations ..................................................................... 48 2.3.8.1 Soil Moisture Content ....................................... 48 2.3.9 Water Balance Approach for Estimation of
Bare Soil Evaporation ...................................................... 49 2.3.10 Model Development and Validation ................................. 50 2.4 Results and Discussion .................................................................. 50 2.4.1 Measurement of Bare Soil Evaporation ........................... 51 2.4.1.1 Estimation of Bare Soil Evaporation in
Experimental Field Conditions ......................... 51 2.4.1.1.1 Bare Soil Evaporation from
Silty Clay Loam Soil in Experimental Field Conditions ........ 53
2.4.1.1.2 Bare Soil Evaporation from Sandy Loam Soil in Experimental Field Conditions ........ 54
2.4.1.2 Estimation of Bare Soil Evaporation in Experimental Laboratory Conditions (Column Study) ................................................. 54
2.4.1.2.1 Estimation of Bare Soil Evaporation in Experimental Laboratory Conditions for Silty Clay Loam Soil ....................... 55
2.4.1.2.2 Estimation of Bare Soil Evaporation in Experimental Laboratory Conditions for Sandy Loam Soil ............................... 57
2.4.2 Comparison of Bare Soil Evaporation Behavior in Experimental Field and Laboratory (Soil Column) Study ........................................ 57
2.4.2.1 Comparison of Bare Soil Evaporation Behavior in Experimental Field and Laboratory (Soil Column) Studies for Silty Clay Loam Soil ........................................... 58
2.4.2.2 Comparison of Bare Soil Evaporation Behavior in Experimental Field and Laboratory (Soil Column) Studies for Sandy Loam Soil ................................................. 58
2.4.3 Evaporation in Relation to Meteorological Parameters .......................................................................... 58
2.4.3.1 Correlation Analysis Between Bare Soil Evaporation and Meteorological Parameters for Sandy Clay Loam (SCL) Soil ........................ 60
2.4.3.2 Correlation Analysis Between Bare Soil Evaporation and Meteorological Parameters for Sandy Loam Soil ........................................... 61
2.4.3.3 Linear Regression Analysis of Evaporation for Silty Clay Loam Soil ..................................... 62
2.4.3.4 Linear Regression Analysis of Bare Soil Evaporation from Sandy Loam Soil ............ 63
2.4.4 Development of Evaporation Estimation Equations (Evaporation Modeling) .................................... 64
2.4.5 Model Validation ................................................................ 65 2.5 Summary ........................................................................................ 68 2.6 Suggestions for Future Work ......................................................... 70 Keywords ................................................................................................ 70 References ............................................................................................... 71
2.1 INTRODUCTION
Evapotranspiration from earth’s surface is one of the most important components of the global water cycle. There is a lack of knowledge in quantification of evapotranspiration and its partitioning into components (bare soil evaporation and plant transpiration). Bare soil evaporation is an important water balance component during early growth stages of irrigated field crops, row crops with incomplete cover and in soils with high water table. Quantification of bare soil evaporation can help in irrigation and environmental management. Evaporation is known to be influencing many other hydrologic and ecological processes too.
