Relationships between sodium adsorption ratio and water productivity of tomato plants affected by NaCl applications at different growth stages

摘要

Under greenhouse condition, tomato plants (Lycopersicon esculentum Mill. cv. Umagna) were planted in the polybags containing a mixture of soil and charcoal husk with a ratio of 2:1 (v:v) and factorial randomized block design was used in this experiment. Four levels of NaCl concentrations (0; 500; 1000 and 2000 mg kg~(-1), respectively) and three stages of plant growth i.e. vegetative stage (2-4 weeks after transplanting, WAT); generative stage (5-12 WAT) and vegetative until generative stages (2-12 WAT) with three replications. Seedlings of grafted beef tomato cv. Umagna with rootstock of Rampart cultivar at the age of 40 days after transplanting (DAT) were planted in the polybags. Plants were initially watered until the field capacity, then each NaCl concentrations of 200 mL polybag~(-1) were given at weekly intervals of 2-4 WAT, 300 mL polybag~(-1) at 5-8 WAT, and 400 mL polybag~(-1) at 9-12 WAT in combination with freshwater. Application of 2000 mg kg~(-1) NaCl significantly affected electrical conductivity (EC), water content and organic C, exchangeable Na~+, Cl~-, Ca~2+, Mg~2+ and sodium adsorption ratio (SAR) of soil mixed media. The negative correlations between SAR and water productivity (WP) of tomato (r = 0.37-0.89) are caused by NaCl applications at different growth stages.