Fig. 3

Microbial respiration (Carbon dioxide emissions) under the NS (a), HS (b), DS (c) and PS (d); Inorganic N (NH₄⁺, NO₃⁻) content under the NS (e), HS (f), DS (g) and PS (h) after 42 days of cultivation. Different letters represent significant correlations in treatments (P < 0.05). Treatments: CK: no glucose or NH₄NO₃; G: glucose; GN: glucose and NH₄NO₃; BS: banana straw; BSN: banana straw and NH₄NO₃; BR: banana root; BRN: banana root and NH₄NO₃.