PARTIAL ROOT DRYING AS STRATEGY FOR WATER USE OPTIMIZATION IN A 'TAHITI' LIME ORCHARD UNDER THE SEMI-ARID OF BAHIA STATE

The management of irrigation using partial root drying (PRD) was tested in an orchard of ‘Tahiti’ lime in the semi-arid conditions of Iaçu, BA. Six treatments were evaluated: T1, T2, T3 (50% ETc PRD) with plants irrigated by a microsprinklers with its position alternating every 7, 14 or 21 days, respectively, and wetting 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 in a fixed position. In T6, at each interval of 21 days, one and two micro-sprinklers were alternatively used per plant. Results demonstrated significant differences in fruit production by the Scott Knott test (p<0, 05). Treatments T5 and T6 had the highest yield with 23.16 and 22.49 t ha^-1, respectively. Treatments with water deficit reduced average production by 30%. Switching sides of irrigation had no benefit over the treatment with the deficit on only one side. Although there were no statistical differences regarding the efficiency of water use, there was a tendency for greater efficiency for T1 and T4 with 9,32 and 9,48 kg/m³, respectively, compared to the control treatment which produced an average of 6,30 kg/m³. Moreover, physiological indicators showed that the treatment with water deficit developed mechanisms to reduce plant transpiration.