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

The pie chart gives information about the three main causes of worldwide

land

degradation

, and the table illustrates the shares of three regions (North

America

, Europe, and Oceania) in

land

degradation

during the 1990s.

Overall

,

it is clear that

over-grazing was a key factor for

land

degradation

in the globe, followed by deforestation.

In addition

, Europe had the biggest proportion of total

land

degradation

,

while

North

America

had the lowest

share

. Over-grazing accounted for the biggest

share

with approximately one-third of all

share

for

land

degradation

, followed by deforestation with 30%.

In addition

,

over-cultivation

stood third rank with 28%, and 7% remaining allocated to other causes of worldwide

land

degradation

. Europe ranked first in total

degradation

with 23%,

while

North

America

stood

last

.

Although

deforestation was the most important factor for

land

degradation

with 9.8%, the roles of

over-cultivation

and over-grazing with 7.7% and 5.5% respectively, should not be ignored. In Oceania, over-grazing with 11.3% was responsible for the biggest

share

of

land

degradation

,

whereas

the figure for

over-cultivation

was zero. In North

America

,

However

,

over-cultivation

was the significant factor for

land

degradation

was 3.3%, over-grazing had almost the half of

share

of

over-cultivation

.