Control of copper-induced physiological damage in okra (Abelmoschus esculentus L.) via Bacillus subtilis and farmyard manure: A step towards sustainable agriculture

Copper (Cu) stress is a serious problem in contaminated soils that causes significant reduction in okra growth and production. To determine the toxic effect of Cu on okra plant and identify an effective way to mitigate Cu toxicity on okra, seeds of okra were inoculated with Bacillus subtilis and sown with farmyard manure. There were 13 treatments (T₀= Control, T₁= 400 mg kg⁻¹ of soil Cu, T₂= 400 mg kg⁻¹ of soil Cu+ B. subtilis, T₃= 400 mg kg⁻¹ of soil Cu+ FYM, T₄= 400 mg kg⁻¹ of soil Cu+ B. subtilis+ FYM, T₅= 450 mg kg⁻¹ of soil Cu, T₆= 450 mg kg⁻¹ of soil Cu+ B. subtilis, T₇=450 mg kg⁻¹ of soil Cu+ FYM, T₈=450 mg kg⁻¹ of soil Cu+ B. subtilis+ FYM, T₉=500 mg kg⁻¹ of soil Cu, T₁₀=500 mg kg⁻¹ of soil Cu+ B. subtilis, T₁₁=500 mg kg⁻¹ of soil Cu+ FYM, T₁₂=500 mg kg⁻¹ of soil Cu+ B. subtilis+ FYM) planned with the complete randomize design (CRD). Results of this research reveal that the okra production and soil physiological properties decreased with the addition of Cu in the soil, this is a new approach for sustainable crop production under Cu stress condition. 500 mg kg⁻¹ of Cu in the soil have the more negative effect on plant growth but negative effect of Cu can be control with the addition of B. subtilis and FYM. Combine application of B. subtilis and FYM improve the soil properties and plant growth by improving the microbial activities, nutrients availability in the soil and production of growth hormones.