Yield response and nitrogen accumulation of furrow-irrigated Burley tobacco (Nicotiana tabacum L.) under deficit irrigation. Preliminary results

A field experiment was conducted using furrow-irrigated Burley tobacco (cv. C104) to compare two deficit irrigation treatments with a full irrigation treatment (control). Two deficit irrigation treatments (50% ETC), imposed either using every row deficit irrigation (DI 50 ) or partial root-zone drying (PRD 50 ), were compared with a full irrigation treatment (100% ETC, FI control). In the DI 50 treatment plants received half of the volume of water uniformly applied to both sides of the row, whereas in the PRD 50 treatment one-half of the root zone was wetted while the other half was maintained dry, thereby the half amount of irrigation water was applied; in particular, the wetted and dry zones were interchanged in two subsequent irrigations. The yield of cured leaves of DI 50 and PRD 50 treatments was 69 and 90% of that of the control, respectively. The dry matter at commercial harvest of DI 50 and PRD 50 was 56 and 88% of the control, respectively. The irrigation water use efficiency (IWUE) of DI 50 and PRD 50 treatments, expressed as kg of cured leaves ha -1 mm -1 of water applied, was 136 and 179% of the control, respectively. At commercial harvest, N accumulated by both DI 50 and PRD 50 plants was 40% or negligible less, respectively, than that accumulated by FI plants. PRD 50 plants showed a greater accumulation of NO 3 -N than plants of other treatments in the second part of growth, although differences were significant with respect to DI 50 but not to FI plants. Considering leaves only, NO 3 -N content showed a trend similar to that reported for the whole plant. Deficit irrigation practice, and PRD 50 in particular, appears an interesting method to supply and save water for Burley tobacco grown in semi-arid areas.