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 chart illustrates why the agronomical territories become less fruitful in 3 regions (North America, Europe, and Oceania) affected by 4 causes (over-grazing, deforestation, over-cultivation, and other reasons) during the 1990s. Units are measured by percentage (%).
Overall, over-grazing is the main factor (35 %) of the agricultural less productivity compared to other reasons (7 %) of worldwide land degradation which is quite higher in Oceania (11.3 %) than North America (1.5 %), that means the percentage of total area degraded is 13 %. According to deforestation level, which is the second main reason for field degradation, Europe stands at the top of the with 9.8 % that caused 23 % of the total land degradation.
As it is seen from the table, over-cultivation is considered one of the main factors (28 %) caused land degradation as well and it is the 2nd major reason (7.7 %) in Europe as opposed to Oceania (0) followed by North America with 3.3 %.