02356naa a2200325 a 450000100080000000500110000800800410001902400500006010000240011024501570013426000090029152012950030065000230159565000220161865000170164065000320165765000090168965300150169865300230171365300110173665300240174765300140177165300320178570000230181770000220184070000240186270000230188670000300190977300910193920661532023-07-03       2017    bl uuuu     u00u1 u    #d7 a10.1590/1807-1929/agriambi.v21n4p273-2782DOI1 aMORAIS, J. E. F. de  aHydrodynamic changes of the soil-cactus interface, effective actual evapotranspiration and its water efficiency under irrigation.h[electronic resource]  c2017  aThe knowledge on soil water dynamics is the basis of crop water management. The soil water balance (SWB) method is used for this purpose. However, its application in cactus may lead to misinterpretation in water efficiency analysis, since it does not consider the amount of water retained in the plant (WRP). This study aimed to evaluate SWB applicability, hydrodynamic changes and water efficiency of forage cactus clones under irrigation. The clones ?Orelha de Elefante Mexicana? (OEM), ?IPA Sertânia? (IPA) and ?Miúda? (MIU) were submitted to irrigation depths (2.5, 5.0 and 7.5 mm) and frequencies (7, 14 and 28 days), in Serra Talhada, PE, Brazil, between March 2012 and August 2013. The SWB was applied, by adding the WRP in the estimate of the effective actual evapotranspiration (ETrEF). The water efficiency indicators were calculated. The actual evapotranspiration on SWB (ETrSWB) overestimated ETrEF and, like other SWB components, it was affected by the factors irrigation depth, frequency and clone. The clone OEM is the most efficient, due to the use of the WRP, while MIU leads to highest gross economic returns for sale of cladodes as seed. As conclusion, the application of the soil water balance method in areas cultivated with cactus species must be accompanied by WRP.  aSoil water balance  aBalanço hídrico  aMeteorologia  aRetenção de Água no Solo  aSolo  aCactáceas  aCactos forrageiros  aCactus  aEavpotranspiração  aModelagem  aWater retained in the plant1 aSILVA, T. G. F. da1 aQUEIROZ, M. G. de1 aARAUJO, G. G. L. de1 aMOURA, M. S. B. de1 aARAÚJO JÚNIOR, G. do N.  tRevista Brasileira de Engenharia Agrícola e Ambientalgv. 21, n. 4, p. 273-278, 2017.