Soil health after 19 years under organic and conventional agriculture and restored prairie grassland

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Braman, Sarah
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The Glenlea long-term study, located in Manitoba was established in 1992 to compare organic, conventional, no-input and restored prairie grass land management practices. Microbial biomass carbon (MBC), microbial metabolic quotient (qCO2), microbial biomass phosphorus, and microbial nitrous oxide quotient (qN2O) were measured to evaluate soil health. MBC and activity were higher in the forage-grain (MBC= 1613 µg-MBC/g-dry soil; qCO2= 0.75 mg CO2-C/g-dry soil/hr) rotation compared to the annual (MBC= 1124 µg-MBC/g-dry soil; qCO2= 0.60 mg CO2-C/g-dry soil/hr). The forage-grain organic system (1718 µg-MBC/g-dry soil) had the highest MBC compared to its conventional (1476 µg-MBC/g-dry soil) counterpart and behaved similarly to the restored grassland prairie (MBC= 1668 µg-MBC/g-dry soil; qCO2= 1.46 mg CO2-C/g-dry soil/hr). Rotation was significant (P<0.0001) for most variables, suggesting rotation has a strong influence on soil microbial characteristics. Agricultural management practices like perennial organic systems, mimic natural prairies and have the greatest capacity to sustain soil microbial life.
soil, health, microbial, biomass, carbon, phosphorus, organic, prairie