Novel nanocomposite and biochar insights to boost rice growth and alleviation of Cd toxicity

Cadmium (Cd) is an unessential and pervasive contaminant in agricultural soil, eventually affecting the food and instigating health issues. The implication of nanocomposites in agriculture attained significant attention to drive food security. Nanocomposites possess exceptional characteristics to stun the challenges of chemical fertilizers that can enhance plant yield and better nutrient bioavailability. Similarly, biochar has the ability to immobilize Cd in soil by reducing mobility and bioavailability. Rice husk biochar is produced at high temperature pyrolysis under anoxic conditions and a stable carbon-rich material is formed. To strive against this issue, rice plants were subjected to Cd (15, 20 mg kg^{- 1}) stress and treated with alone/combined Ca + Mg (25 mg L^{- 1}) nanocomposite and rice husk biochar. In our study, growth and yield traits showed the nurturing influence of Ca + Mg nanocomposite and biochar to improve rice defence mechanism by reducing Cd stress. Growth parameters root length 28%, shoot length 34%, root fresh weight 19%, shoot fresh weight 16%, root dry weight 9%, shoot dry weight 8%, number of tillers 32%, number of grains 20%, and spike length 17% were improved with combined application of Ca + Mg and biochar, with Cd (20 mg kg^{- 1}), rivalled to alone biochar. Combined Ca + Mg and biochar application increased the SPAD 23%, total chlorophyll 26%, a 19%, b 18%, and carotenoids 15%, with Cd (20 mg kg^{- 1}), rivalled to alone biochar. MDA 15%, H₂O₂ 13%, and EL 10% were significantly regulated in shoots with combined Ca + Mg and biochar application with Cd (20 mg kg^{- 1}) compared to alone biochar. POD 22%, SOD 17%, APX 18%, and CAT 9% were increased in shoots with combined Ca + Mg and biochar application with Cd (20 mg kg^{- 1}) compared to alone biochar. Cd uptake in roots 13%, shoots 14%, and grains 21% were minimized under Cd (20 mg kg^{- 1}) with combined Ca + Mg and B. pumilus application, compared to alone biochar. Subsequently, combined Ca + Mg and biochar application is a sustainable solution to boost crop production under Cd stress.