Combined Effects of Biochar and 2–Hydroxybenzoic Acid on Ameliorating the Nutritional Status, Productivity and Fruit Quality of Salt Stress-Imposed Mango Trees

Although mango is a valuable crop with high market value worldwide, it is very sensitive and its productivity and quality are greatly affected by salinity. To ameliorate mango yield and quality attributes, several direct and indirect tactics should be adopted to alleviate the hazardous impacts of soil salt. Hence, along two seasons of 2020 and 2021, mango trees imposed to salt stress were treated by biochar (B) and salicylic acid (SA) as possible alleviators of salinity. The influences of three B application rates (0, 2 and 4 kg/tree, denoted as B0, B2 and B4, respectively) and four concentrations of SA (0, 2, 4 and 8 µM, abbreviated as SA0, SA2, SA4 and SA8, respectively) on mango yield and quality were assessed. For increasing chlorophyll content (with excluding B0 × SA0 and B0 × SA2) and reducing proline content (with excluding B0 × SA0, B0 × SA8, B2 × SA0 and B8 × SA0), all other possible interactions between B × SA showed similar favorable effects. It is worth to note that B4 × SA4 and B4 × SA8 were the most established and compatible practices for boosting most of the significant nutrient contents, yield attributes and quality traits of mango under salty soil. Briefly, it could be deduced that application of incorporating biochar at a rate of 4 kg in rhizosphere of mango trees plus foliage spraying of salicylic acid 4 µM can be counseled as a costless and practicable treatment for sustaining mango fruit yield and quality in salty soils.