PDC Soil Health & Regeneration Techniques 3

Question 1

What is 'biochar' and how does it primarily benefit soil in a permaculture system?

Accepted Answer

Charred organic matter that provides long-term carbon sequestration and microbial habitat

Answer

Biochar is charred organic material with a porous structure that persists in soil for centuries, improving microbial habitat, water retention, and nutrient holding capacity.

Question 2

Actinomycetes (actinobacteria) in healthy soil are responsible for producing which recognizable characteristic?

Accepted Answer

The earthy petrichor smell of healthy soil

Answer

Actinobacteria produce geosmin, the compound responsible for the characteristic earthy 'petrichor' smell associated with healthy, biologically active soil.

Question 3

Which nitrogen-fixing tree is widely used in permaculture agroforestry to rapidly build soil fertility through chop-and-drop mulching?

Accepted Answer

Leucaena (Leucaena leucocephala)

Answer

Leucaena is a fast-growing nitrogen-fixing tree widely used in tropical permaculture systems for chop-and-drop mulching, providing high-nitrogen biomass to build soil.

Question 4

What does 'cation exchange capacity' (CEC) measure in a soil test?

Accepted Answer

The soil's ability to hold positively charged nutrient ions

Answer

CEC measures the soil's capacity to hold and exchange positively charged nutrient cations (Ca²⁺, Mg²⁺, K⁺, Na⁺), indicating fertility and nutrient availability.

Question 5

In Elaine Ingham's soil food web model, what role do protozoa play in nutrient cycling?

Accepted Answer

They graze on bacteria and release nitrogen in plant-available form

Answer

Protozoa graze on bacteria and excrete excess nitrogen as ammonium (NH4+), releasing it in a plant-available form in the rhizosphere near plant roots.

(PDC) Permaculture Design Certification Practice Test

(PDC) Permaculture Design Certification Practice Test

PDC Soil Health & Regeneration Techniques 3