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

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

degradation

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

further

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28% of global

degradation

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is

due to

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over-cultivation

Correct article usage

the over-cultivation

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of crops. Other

causes

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account for only 7% collectively. These

causes

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

degradation

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due to

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deforestation,

while

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the impact of

this

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

overall

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percentage of land degraded (23%),

also

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suffered from

over-cultivation

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

In contrast

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, Oceania had 13% of degraded farmland and

this

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was mainly

due to

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

causes

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of

this

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were

over-cultivation

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

Overall

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,

it is clear that

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Europe suffered more from farmland

degradation

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than the other regions and the main

causes

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there were deforestation and

over-cultivation

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.