Teaching Organic Farming and Gardening

Soil Biology and Ecology

38 | Unit 2.3

resistant fraction 10% 100:1 C:N

Total in this fraction

600 kg C/ha

6 kg N/ha

Moderately 60% 40:1 C:N _______ kg C per ha in biomass

decomposable Total in this fraction _______ kg C per ha respired as CO 2

fraction ________ C (kg/ha) _______ kg N per ha in biomass

________ N (kg/ha) _______ kg N per ha in mineral N

easily 30% 20:1 C:N _______ kg C per ha in biomass

decomposable Total in this fraction _______ kg C per ha respired as CO 2

fraction ________ C (kg/ha) _______ kg N per ha in biomass

________ N (kg/ha) _______ kg N per ha in mineral N

________TOTAL Kg N MINERALIzED PER HECTARE

QUestiOns tO POnder

• What happens to the N incorporated in the
soil biomass? Is this the end of the story?

• What is the fate of mineralized N/

• How would organic and conventionally

fertilized farm soils differ with respect to the
timing of mineral N release?

• Why is it important to consider three

fractions for organic matter inputs?

Hands-On Exercise