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 first given chart indicates the major causes of unproductive farmland, while the sencond chart illustrates how these factors affected thee regions North America, Europe and Oceania during the 1990s.
Overall, the primary reason for agriculture land degradation is over-grazing. It is also notiable that Europe had a higher proportion of degraded land than other two regions in the years mentioned.
Around 35% of worldwide farmland degradation due to over-grazing. This figure for deforestation is slightly lower, at 30%. Over-cultivation accountes for 28% of unproductive land causes, and the other reasons are only took up 7%.
In the 1990s, the proportion of degraded land in Europe was 23% and this was mainly caused by deforestation. Over-grazing is the primary reason why Oceania’s farmland became less productive and result in about 13% unproductive land. The smallest proportion of land degraded was 5% in North America with the main cause was over-cultivation.