The use of mulch in cultivating the forage cactus optimizesyield in less time and increases the water use efficiency ofthe crop.

Measurements of crop evapotranspiration (ETC) and crop coefficients (kC)incactus have not yet been adjusted for the phenological stage using conserva-tion practices (i.e. mulching). In this study, soil water dynamics, ETCandkCwere measured in the forage cactus under cultivation systems with (WM) andwithout (NM) the use of mulch in the semi-arid region of Brazil.Opuntiastrictawas subjected to irrigation depths based on a percentage of the referenceevapotranspiration (ET0) (rainfed, 25, 50, 75 and 100%) and to two systems ofcultivation: WM and NM. Over time, the phenophases (?Ph) were established;the soil water balance components were calculated and the crop yield wasevaluated at harvest. The use of 8.2 Mg ha1mulch led to almost no reducedwater consumption by the crop when compared to the NM system; however,the mulch did maximize yield, at 839C day, when irrigated with 50% ET0. ThekCvalue was higher under the WM system, with the differences decreasingthroughout the cycle (?PhI, 36%;?PhII, 27%;?PhIII, 23%;?PhIV-HT, 17%; and?PhIV-RF, 14%). Therefore, the use of mulch in cultivating the cactus opti-mized forage production in less time and significantly increased the water useefficiency of the cro