Conversion between evapotranspiration references and methods.

Ratios of reference evapotranspiration for alfalfa (ET r) and for grass (ET0) are evaluated using\nmeasured ETr and ET,, from lysimeter systems at Kimberly, Idaho and Bushland, Texas. In\naddition, ratios are evaluated using estimates by the Kimberly Penman and ASCE Penman-Monteith\nevapotranspiration methods. An ET reference conversion equation from FAO-56 is\nalso compared. The ASCE-PM and Kimberly Penman methods predict differently for both ET,\nand ET0 so that ratios of ETr / ET° computed from both methods behave differently Ratios of\nETr / ET0 from lysimeter measurements averaged 1.15 at both locations.