Investigation of the effects of biochar and wood vinegar on morpho-physiological traits of African marigold under salt stress

Recently addition of cheap and available organic compounds to soils has attracted attention of many researchers. Mineral salts are an important plant stress factor, having adverse impacts on urban trees and road verges where salts are used for de-icing.

Here we investigated the effects of biochar (0, 5, 10 ton/ha) and wood vinegar (0, 2000 and 4000 L/ha) to mitigate salt-induced stress (0.4, 2.1 and 4.2 dS m−1), simulating road salt additions in a factorial glasshouse experiment in the university of Mohaghegh Ardbili.

Results showed that increasing slat stress reduced flower number, flower size, flowering period and total phenolic compound and leaf relative water content, whereas electrolytic leakage and total phenolic compound were increased. Wood vinegar reduced electrolyte leakage in comparison to biochar and control, increased relative water content, flower number and stem diameter, but wood vinegar did not affect flowering period and flower size. Plants treated with biochar showed an increase in all vegetative traits and relative water content, while there was a significant decline in electrolyte leakage. The highest plant dry weight was recorded in plant treated with 10 ton/ha of biochar under 0.4dS m−1 . Under severe salt stress (4.2 dS m−1) the highest dry weight was recorded in plant treated with biochar and 4000 L/ha of wood vinegar. Leaf chlorophyll content and chlorophyll stability index (RSI) under both normal and salt stress condition in biochar-treated plant were significantly higher than control plants. Increasing salt levels significantly increased enzyme activity of peroxidase and ascorbate peroxidase. Under low stress condition treatment did not affect enzyme activity, while under high salinity stress condition biochar and wood vinegar reduced enzyme activity.

Results of present experiment showed that biochar and wood vinegar are able to mitigate salt stress in marigold pants. It seems these compounds alleviate salt stress by optimizing plant water relations and soil conditions.