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 shows that there are four main

causes

of farmland becoming degraded in the world today. Globally, 65% of

degradation

is caused by too much animal grazing and tree clearance, constituting 35% and 30% respectively. A

further

28% of global

degradation

is

due to

over-cultivation

Correct article usage

the over-cultivation

show examples

of crops. Other

causes

account for only 7% collectively. These

causes

affected different regions differently in the 1990s, with Europe having as much as 9.8% of

degradation

due to

deforestation,

while

the impact of

this

on Oceania and North America was minimal, with only 1.7% and 0.2% of land affected respectively. Europe, with the highest

overall

percentage of land degraded (23%),

also

suffered from

over-cultivation

(7.7%) and over-grazing (5.5%).

In contrast

, Oceania had 13% of degraded farmland and

this

was mainly

due to

over-grazing (11.3%). North America had a lower proportion of degraded land at only 5%, and the main

causes

of

this

were

over-cultivation

(3.3%) and, to a lesser extent, over-grazing (1.5%).

Overall

,

it is clear that

Europe suffered more from farmland

degradation

than the other regions and the main

causes

there were deforestation and

over-cultivation

.