The pie chart below shows the main reasons why agricultural land becomes less productive. The table shows how these causes affected three regions of the world during the 1990s.

The pie chart presents the major causes of the reduction in agricultural

land

,

while

the table compares how different regions of the world were affected by them.

This

information is presented for North America, Europe, and Oceania for the period from 1990 to 1999.

Overall

, Europe suffered more from farmland

degradation

than the other regions, and the main reasons were deforestation and over-cultivation. It is clear from the pie chart that there were four main sources of global

land

degradation

. Over-grazing causes the largest share of

land

degradation

with 35%, followed by deforestation (30%). Over-cultivation ranks

third

with 28%, and the remaining 7% results from other factors. From the table, we can see that each of these four factors affected the three regions differently. Europe has almost 9.8% of

degradation

due to

deforestation,

while

the impact of

this

was minimal

to

Change preposition

in

show examples

Oceania and North America, with only 1.7% and 0.2% of

land

affected respectively.

In contrast

, over-grazing was the leading cause of farmland reduction in the Oceanic region (11.3%) but only accounted for less than 2% of

land

degradation

in North America.