A field study was conducted on sugar beet during a two-year period to investigate the effects and comparison of different irrigation methods and treatments on crop yield, irrigation water use efficiency (IWUE), and pan coefficient determination in a semiarid region with limited water resources. The experiments were in complete randomized blocks design. Three replications were used with different levels of irrigation water amounts (25, 50, 75, and 100%), evapotranspiration (ET) of sugar beet seasonal water requirement with surface drip tape (SDT), and conventional furrow irrigation method (CFI), with and without soil and water monitoring, and comparison with CROPWAT modeling. The variety of sugar beet was Rasool. The highest and lowest average irrigation water use efficiencies on the basis of root yield with 16.16 and 9 kg/m3 , and sugar yield with 3.82 and 1.33 kg/m3 , for both experimental years was achieved under different irrigation treatments of T4 (25% ET) SDT and CFI, respectively. The results of ...

A field study was conducted over two years on maize at Islam Abad Research Station at 34°7′42′′N and 46°27′23′′E and elevation of 1348 m a.s.l in Kermanshah Province, western Iran in order to compare the effects of different irrigation methods and treatments on irrigation water use efficiency, crop yield, yield response factor, pan and seasonal crop coefficients, and other maize parameters. The experiment was a complete randomized block design with three replicates. During the study, irrigation water was applied at 40, 60, 80 and 100% of the maize seasonal water requirement for different surface drip tape (SDT) treatments, and 100% only for conventional furrow irrigation treatments with and without soil and water monitoring. The results showed that by using the above-mentioned different drip tape and surface treatments with soil and water monitoring, maize seasonal irrigation water use savings of 81, 71, 61, 52 and 36% were achieved compared with local conventional furrow irrigation without any soil, water and root monitoring, respectively. The yield response factor (K _y), seasonal crop (K _c) and pan coefficient (K _p) for maize were 0.80, 0.76 and 0.97, respectively.

The accurate estimation on crop evapotranspiration (ETc) and crop coefficients is of assistance infield proper irrigation and water management. In present study, experiments were carried through out two years (i.e., 2012 and 2013) to determine water requirements (single and dual crop coefficients of basil) by using a few drainable lysimeters in a semi-arid region in Iran. Three lysimeters were used for grass evapotranspiration while three others were used to estimate bare soil evapotranspiration. Also, basil seeds were planted in six lysimeters and two groups, including group A where plant grew continually until the end of flowering stage, and group B where the plant was harvested three times after it reached a height of 0.25-0.30 m. The average water requirements of basil in two lysimeters including groups A and B were determined to be 636.8and 849mm, respectively. Finally, single and base crop coefficients for lysimeters in group A for the initial development and middle stages of basil growth were determined to be as 0.71, 1.11, 1.39and 0.57, 0.97, 1.26, respectively. Moreover, SIMDualKc, a soil water balance and irrigation scheduling model, was developed by using dual crop coefficient approach for ETc estimation. The model was calibrated and validated by comparing the measured and simulated Dual Kc values for basil for a semi-arid climate. The results indicated with low RMSE and MBE and highR²=0.83,the model was capable of accurate in proper irrigation, planning and scheduling in semi-arid climates.