The influence of drip or furrow irrigation on yield and quality of Burley tobacco under saline conditions

Irrigation methods are critical to alleviate salinity problems in Mediterranean areas where saline waters are frequently used to irrigate crops. Field experiments were conducted on Burley tobacco (Nicotiana tabacum L.) cv. C104 in Southern Italy over two years to compare drip versus furrow irrigation when waters of increasing salinity were used. Two irrigation methods (drip and furrow) and six irrigation treatments (rainfed control, RC; fully-irrigated with water at 0.5 dS m-1 electrical conductivity (ECw), NW; at 2.5 dS m-1 ECw, SW1; at 5 dS m-1 ECw, SW2; 10 dS m-1 ECw, SW3; at 15 dS m-1 ECw, SW4) were factorially combined. Over the growing season the electrical conductivity of soil (ECe) across the 0.6 m top profile increased with increasing salinity of the irrigation water at very low rates but more in drip- than in furrow-irrigated plots. Salinity of the irrigation water did not affect yield of cured leaves in the SW2 - SW4 range. Nevertheless, in the same range quality was generally depressed due to increases in leaf Cl- and decreases of filling power. Overall, furrow irrigation determined significantly greater yield, mean cured leaves weight and IWUE as compared with drip irrigation (1.7 vs. 1.5 Mg ha-1, 5.8 vs. 5.2 g, 5.9 vs. 5.4 kg ha-1 mm-1).