Irrigação com déficit hídrico e eficiência do uso de água em Lima ácida “thaithi” no semi-árido baiano

Abstract

The present work had as objective to test strategies for irrigation management with deficit, focusing the technique of partial root drying and evaluating its impacts on fruit yield, on water use efficiency (EUA) and on physiologic behavior of five years old Tahiti lime acid under semi arid conditions of Iaçu county, Bahia State. The treatments were: T1, T2, T3 (50% ETc PRD) formed from plants irrigated by a microsprinklers with his position alternating every 7, 14 and 21 days, respectively, wet themselves on opposite sides of the root system; T4 ( DI 50% ETc) irrigation was fixed on one side using one emitter per plant, T5 (100% ETc) was the control treatment using two microsprinklers per plant with fixed position; In case of T6, at each interval of 21 days, one and two microsprinklers were used per plant, alternatedly. There was significantly (P<0.05) higher yields for treatments T5 and T6 with 23,16 and 22,49 t/ha/year, respectively, as well as higher stomatal conductance and transpiration. Strategies PRD showed no advantages over treatment with fixed deficit. Treatments with water deficit, T1 and T4 showed higher efficiency of water use with 9,32 and 9,48 kg/m³, respectively, even with a marginal reduction in yield. Treatment T1 responded physiologically with larger automatic control and resulted in higher yield with 17,12 t/ha/year among the strategies of the PRD. The production was not affected with deficit of 25% that is a feasible alternative for increase water use efficiency in the orchard. Depending on cost/water scarcity ratio, a water deficit more accentuated might be adopted as alternative for irrigation management, where it might be expected to decrease 30% in yield when 50% of the irrigated is reduced under evaluated conditions.