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Pasture irrigation under center pivot machines is becoming popular in Brazil in the last 7 years, in order to raise cattle for the international meat (non-confined) demand. Field technicians are considering pasture irrigation management a technical challenger to overcoming in the next years, because under rotary pasture, parcels are simultaneously at different development stages (leaf area index) and a single irrigation depth for the whole area is not considered anymore the best alternative. In this study a model was developed for the application of different irrigation depths in each portion of the pivot (pizza shape plots). The model proposed in this study considers: i) the capacity of the pivot-center to apply different water depths in the whole area; ii) development stage of crop in each plot iii) cattle return period for grazing in-determined plot (pasture cycle fixed); and iv) potential of pasture development during the agronomic year. To compute the crop coefficient (Kc) variable in the model were used sinusoidal variation rate of Kc, according to the resting period. The model was applied for hypothetical pastures conditions under rural areas of Piracicaba and Pereira Barreto municipalities, in the State of So Paulo, Brazil. The models sensitivity for the irrigation depths applied was observed for the different stages of Tanzania grass development under the center-pivot, according to the variable climatic conditions of each region.