Explanation for the difference in primary productivity between temperate grassland and intensively cultivated?

Question

Pliz may I have the answer today . Thanks.

Its worth (3 marks).

Answer 1

That would be an ecumenical question!

Answer 2

Its in the soil structure.  As soon as you run a tractor across any virgin land the soil is compressed and damaged thus making the ground less productive.

Another consideration is in the biodiversity.  Temperate grassland will have many ecological niches for various species to live and thrive.  When the soil is farmed, all this natural biodiversity is replaced by a monoculture.  Any native plants that try to regain a foot-hold are called weeds and suppressed by chemical means.

With less plant life there is less insects and therefore less vertebrates (birds etc).  Opportunists like rats may move into the area in response to the new food source but this hardly replaces the biodiversity that once existed.