Nutrient Cycling

- In small scale ecosystems.

Stores

1

2

3

Flows

1

2

3

Inputs

Outputs

As before but which stores are bigger and which are smaller?

And the same question for flows

(and why the difference?)

 

                                                   

                       

Figure 17.  Nutrient cycling models for world biomes (after Gersmehl 1976). 

Nutrient Cycling models for BIOMES

But these are large scale ecosystems!

(Gersmehl)

Nutrient Cycling for a Deciduous Wood.

Nutrient cycling for a Corn / Beef farm

The 1st October saw the start of the muirburn season in Scotland – a process which ensures the re-generation of heather to provide a mixture of young, intermediate and mature heather used as a food source, nesting habitat and shelter by the many animals and birds which inhabit moorland.

Snow reveals the pattern of muirburn strips. MOORLAND ECOSYSTEM

On most kinds of moorland, over time, plant nutrients become locked away and relatively unavailable in the woody stems of heather, and other dwarf-shrubs, and in the very slowly decaying plant litter.

This also results in reduced food quality for herbivorous animals. Fire helps to release the unavailable nutrients for further use and, biologically, it is like much accelerated decomposition.

Soluble mineral plant nutrients like potassium, calcium and magnesium become more available, the soil becomes less acid, and charcoal particles are deposited and become incorporated into the soil.

After a fire, regenerating heather shoots may contain up to twice the amount of nitrogen and phosphorus as shoots from pre-fire heather bushes, although this effect disappears quite rapidly over the first four to five years after burning.