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

The pie chart compares three main reasons of land degradation worldwide and the table shows the way these factors have affected north America, Europe and oceania over a period of ten years.

It is clear that over-grazing was the main reason of decreasing quality of the soil. Also we can see that Europe had the highest percentage of land degradation over the 10-year period.

According to the pie chart, over-grazing had the most negative effects on agricultural lands with 35%, and is followed by deforestation with 30%. Over-cultivation and other reasons constituted an overall 35% of negative causes with 28% and 7% respectively.

Lands in Europe were highly affected with 23% of land degradation causes, divided to 9.8% of deforestation, 7.7% of over-cultivation and 5.5% over-grazing. Oceania was the second most affected region with a full 13% of degradation, and North America is ranked third with 5% of less productivity on its lands.