Short-Term Effects of Crude Botanical Extracts and Rhizosphere Soils on Soil Respiration and β-Glucosidase Activity

Garlic extract most persistently reduced basal soil respiration and cumulative CO2-C over a 5-week incubation, while garlic rhizosphere soil also strongly lowered β-Glucosidase activity by 57.4%.

• Why it matters: Plant-derived compounds may alter microbial carbon turnover, but their short-term effects on soil respiration and β-Glucosidase activity remain poorly documented.
• What they did: In a laboratory incubation (n = 3), crude ethanolic extracts and rhizosphere soils from garlic, ginger, turmeric, moringa, and aloe vera were compared with untreated soil for 5 weeks, measuring CO2-C release and β-Glucosidase activity.
• The result: Extracts reduced basal respiration and cumulative CO2-C versus control, with rhizosphere soils stimulating CO2-C release from week 2 onward; β-Glucosidase activity fell 4.3% with garlic extract, 14.0% with aloe vera extract, and 57.4% in garlic rhizosphere soil.