Background:Salinity stress is a limiting factor for many crops and combating it is one of the major problems of the agricultural sector in arid regions. Therefore, applied research in this field can solve some of the existing problems, especially in saline conditions. Also, nutrition management is one of the ways to increase crop production in saline conditions in many plants and there are reports of positive effects of calcium and humic acid as an inducer of increased tolerance to salinity stress.
Aim: This study was conducted to investigate the effect of foliar application of calcium nitrate and different levels of humic acid on morphological, biochemical, functional and qualitative characteristics of fruit in greenhouse tomato planting in saline conditions.
Methodology: The experiment was performed as a factorial experiment in a randomized complete block design with 3 replications including the effect of three factors, two salinity levels (including basic nutrient solution and electrically conductive nutrient solution 4.5 dS/m), four humic acid foliar application levels (0, 0.4, 0.8 and 1.6 g/l) and two levels of calcium nitrate (0 and 6 g/l) on tomatoes by hydroponic cultivation in greenhouse conditions. Finally, morphological traits of stem diameter, leaf area, fresh and dry weight of shoots, plant height, internode length, number of panicles, average number of flowers and fruits per panicle and total plant yield, biochemical and physiological characteristics of total chlorophyll index, Chlorophyll a, chlorophyll b, carotenoids, proline, ion leakage and relative water content of leaves, amount of phosphorus, potassium, sodium, calcium and magnesium in shoots and quantitative and qualitative characteristics of fruit weight per panicle, percentage of dry matter, grade Stiffness, soluble solids, pH, EC, vitamin C, acidity and lycopene were evaluated.
Results: The results of variance analysis showed that salinity, calcium nitrate and humic acid treatment had a stat