Abstract
Purpose Plant growth and grain yield of most of the crops are reduced on saline-sodic soils. Different organic and inorganic amendments have been used to increase plant growth and productivity on salt-affected soils. However, the role of cotton shell biochar (CSBC) for increasing salt tolerance of plants grown on saline-sodic soils has not been investigated yet. Therefore, the current study was intended to estimate the impact of cotton shell biochar (CSBC) addition @1 and 2% for ameliorating Na-induced phytotoxicity in quinoa grown on saline-sodic soil. Materials and methods Quinoa plants were grown on saline-sodic soil with and without CSBC addition. Different physiological attributes were measured at vegetative stage. Plants were harvested at maturity when growth and grain yield were recorded. Results and discussion Results revealed that plant biomass, grain yield, stomatal conductance, relative water contents, and chlorophyll contents of quinoa were declined by > 20%, 18%, 23%, 27%, and 16%, respectively under salt stress. Excessive uptake of Na decreased the uptake of K and K:Na, and caused the overproduction of H2O2 (62%) and lipid peroxidation (58%) in quinoa. The CSBC addition @2% was more effective than 1% in ameliorating the negative impacts of Na toxicity on plant growth and physiology. Amendment of saline-sodic soil with 2% CSBC increased plant growth, water contents, stomatal conductance, and chlorophyll contents by 60%, 36%, 41%, and 43%, respectively as compared to saline-sodic soil without CSBC. There was a slight increase in soil EC after the addition of CSBC. Additionally, 2% CSBC limited the uptake of Na and caused a 43%, 48%, and 75% increase in superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities to ameliorate the oxidative stress. Conclusions It was concluded through multivariate analysis that 2% CSBC was very promising in reducing Na toxicity and increasing plant biomass and grain yield of quinoa in saline-sodic soils.