## 2 Materials and Methods
### Evaportranspiration Measurements  
The actual evapotranspiration (ETa) was measured using the residual of energy balance (REB) method with a combination of surface renewal and eddy covariance techniques. The sensible heat flux density (H) was estimated by the SR and EC methods to calculate the latent heat flux density (LE) using the REB approach [1; 27; 28; 29; 30; 31; 32]. A full flux density tower was set up at the experimental sites (Figure 1). Two chromell-constant thermocouples model FW3 with 76.2 um diameter (Campbell Scientific, Inc., Logan, UT, USA) were used to measure high frequency temperature data for computing uncalibrated sensible heat flux (H0) using the SR technique. An RM Young Model 81000 RE sonic anemometer (RM Young Inc., Traverse City, MI, USA) was used to collect high frequency wind velocities in three orthogonal directions at 10 Hz to estimate H for the latent heat flux density calculations using the EC technique. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Experimental**} & \multirow{3}{*}{**Irigation**} & \multicolumn{8}{c}{**Soil Texture**} \\ \cline{3-13}  & & \multicolumn{4}{c}{**Sand (\%)**} & \multicolumn{4}{c}{**Silt (\%)**} & \multicolumn{4}{c}{**Clay (\%)**} \\ \cline{3-13}  & & \multicolumn{4}{c}{**Generic Horizon (m)**} & \multicolumn{4}{c}{**Generic Horizon (m)**} & \multicolumn{4}{c}{**Generic Horizon (m)**} \\ \cline{3-13}  & & **0-0.3** & **0.3–0.6** & **0.6–0.9** & **0.9–1.2** & **0-0.3** & **0.3–0.6** & **0.6–0.9** & **0.9–1.2** & **0-0.3** & **0.3–0.6** & **0.6–0.9** & **0.9–1.2** \\ \hline A & Furrow & 44 & 47 & 42 & 48 & 45 & 45 & 51 & 46 & 11 & 8 & 7 & 6 \\ B & Furrow & 40 & 50 & 75 & 84 & 40 & 38 & 20 & 12 & 20 & 12 & 5 & 4 \\ C & Border & 32 & 26 & 88 & 95 & 55 & 55 & 9 & 4 & 13 & 19 & 3 & 1 \\ D & Border & 69 & 92 & 82 & 86 & 18 & 5 & 10 & 8 & 13 & 3 & 8 & 6 \\ E & SDI & 54 & 40 & 28 & 31 & 28 & 38 & 45 & 37 & 18 & 22 & 27 & 32 \\ F & SDI & 22 & 19 & 33 & 63 & 45 & 46 & 45 & 32 & 33 & 35 & 22 & 5 \\ G & ASI & 26 & 22 & 23 & 17 & 39 & 49 & 54 & 54 & 35 & 29 & 23 & 29 \\ H & LMI & 14 & 11 & 10 & 10 & 19 & 6 & 32 & 20 & 67 & 83 & 58 & 70 \\ I & LMI & 35 & 44 & 51 & 30 & 31 & 25 & 28 & 53 & 34 & 31 & 21 & 17 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Irrigation methods and soil texture of the experimental sites. “A” through “I” represent alfalfa experimental sites. SDI, LMI, and ASI abbreviate subsurface drip irrigation, linear move sprinkler irrigation, and automated surface irrigation, respectively. Figure 1: A fully automated surface renewal and eddy covariance evapotranspiration tower (**a**) and a multiple depths soil moisture sensor monitoring station equipped along with NDVI and rule technologies sensors at site B (**b**). Tule technologies sensor measures actual ET using surface renewal method. The measurements of soil heat storage at three different locations using three HFT3 heat flux plates (REBS Inc., Bellevue, WA, USA) inserted at a 0.05 m depth below the soil surface, and the measurements of soil temperature using three 107 thermistor probes (Campbell Scientific, Inc., Logan, UT, USA) at three depths in the soil layer above the heat flux plates were used to estimate ground heat flux (G). An NR LITE 2 net radiometer (Kipp & Zonen, Ltd., Delft, The Netherlands) was used to measure net radiation (Rn). The data were recorded using a combination of a Campbell Scientific CR1000X data logger (Campbell Scientific, Inc., Logan, UT, USA) and a CDM-A116 analog input module (Campbell Scientific, Inc., Logan, UT, USA)). Except for the soil sensors, all other sensors were set up at 1.8 m above the ground surface. As an additional sensor, Tule sensor (Tule Technologies, Inc., Oakland, CA, USA) was used in some of the monitoring sites to estimate ETa using a simple surface renewal technique.