Effect of foliar application of Fe and banana peel waste biochar on growth, chlorophyll content and accessory pigments synthesis in spinach under chromium (IV) toxicity

Chromium (Cr) toxicity is becoming one of a major issue for the cultivation of crops. Toxicity of Cr directly affects synthesis of chlorophyll and restricts Fe intake, which decreases crop growth. It is well documented that the reduction of Cr toxicity through the application of biochar. However, current experiment was carried out to investigate any positive effect of, banana peel waste biochar (BC) and foliar application of Fe (FFe) on growth and chlorophyll content of Spinacia oleracea L. under different levels of Cr toxicity. Seeds of Spinacia oleracea L. were grown under three levels of Cr i.e. control (Cr0), Cr35 (35 mg Cr kg(-1) soil) and Cr70 (70 mg Cr kg(-1) soil). Analyzed data confirmed that Spinacia oleracea L. seeds grown in 1% BC amended soils and 1000mM FFe, showed significantly better growth, Fe uptake and chlorophyll content as compared to control at Cr35 and Cr70. A significant improvement in shoot length (16.9 and 26.9%), root length (16.3 and 20.9%), plant fresh (15.5 and 28.3%) and dry weight (70.3 and 77.8%) as compared to control under Cr35 and Cr70, respectively, validated the efficacious functioning of 1% BC and FFe to mitigate Cr toxicity in Spinacia oleracea L. It is concluded that both 1% banana peel waste BC and 1000mM FFe have potential but sole application of FFe is more effective to alleviate Cr toxicity in Spinacia oleracea L. Fortification of Fe by foliar application is more effective comparative to banana peel waste biochar for improvement in growth, chlorophyll content and accessory pigments synthesis in spinach under chromium (IV) toxicity.