The pie chart below shows the main reason why agriculutural land become less productive. The table shows how these causes effected three regions of the world during the 1900s

The pie chart outlines the key factors as to why

land

used for agriculture produces less over time,

while

the table gives a breakdown of the effect these

causes

had on agricultural

land

in three regions during the 1990s.

Overall

, over-grazing,

deforestation

, and

over-cultivation

were all significant

causes

of

land

degradation globally.

Furthermore

, Europe had the highest total degraded

land

,

whereas

North America had the least. In terms of the

causes

of

land

degradation, over-grazing was the most significant factor in the

land

with 35% of the

land

being affected in

this

way.

This

was closely followed by

deforestation

(30%) and

over-cultivation

(28%), with the remaining 7% being made up of other

causes

Regarding the table,the North American region had the lowest amount of degraded

land

at just 5%. Of

this

land

, about two-thirds was damaged by

over-cultivation

, just under a third by over-grazing, and a minimal amount by

deforestation

.

In contrast

, almost a quarter (23%) of arable

land

in Europe was degraded. The main factor in Europe was

deforestation

, with 9.8% of total

land

affected in

this

way.

Over-cultivation

and over-grazing were 7.7 % and 5.5% respectively. In Oceania, the main cause of

land

degradation was clearly over-grazing with 11.3% of

land

being affected by

this

out of a total of 13% of

land

degraded in total.

Conversely

,

over-cultivation

appeared to play no role in

this

part of the world,

while

deforestation

affected only a relatively small amount (1.7%)