Effects of Biochar and Chitosan on Growth and Yield of Rice (<i>Oryza sativa</i> L.) Under Salt Stress

Salinity is one of the leading abiotic stresses that hindering growth and yield of rice. Biochar (BC) and Chitosan (CHT) has been shown to promote growth and yield of plants. However, it still unexplored whether the use of soil amendment BC and exogenous CHT can alleviate the detrimental effects of salt stress on rice. Hence, the current study explored the effect of BC and CHT to rice variety BRRI dhan100 grown under 80 mM NaCl stress conditions. The experiment was sequenced according to a Completely Randomized Design with three replicates. Six different treatments namely control (control, neither salt nor biochar or chitosan), BC (5%), CHT (200 ppm), NaCl (80 mM), NaCl plus biochar (NaCl+BC, 80 mM NaCl plus 5% biochar) and NaCl plus chitosan (NaCl+CHT, 80 mM NaCl plus 200ppm chitosan) were used in the experiment. The results confirmed that salt stress negatively affected plant height, number of tillers, leaf area, total chlorophyll concentrations, SPAD value, yield and yield contributing characters of rice plants. However, MDA content and Na<sup>+</sup>/K<sup>+</sup> ratio significantly increased under salt stress. The use of biochar and chitosan led to significant increases in plant height, leaf area, total chlorophyll concentrations, SPAD value, yield as well as yield contributing characters of salt-stressed BRRI dhan100 plants; however these treatments cause significant decreases in MDA content and Na<sup>+</sup>/K<sup>+</sup> ratio in the salt-stressed rice plants. The results demonstrated the significance of biochar and chitosan in mitigating the detrimental impacts of salt on growth and yield of BRRI dhan100 plants.