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 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 graph illustrates the major causes of the decreasing productivity in farming land, and the table represents the consequences made by those changes in terms of agricultural space in three different areas in the earth in 1990s.

From the first graph, it is clear that too much grazing was the most important factor of all four reasons resulting the dropping of farming space all over the world, as 35% of total land were diminishing land because of over-grazing. And the other two vital factors were deforestation and unscientific cultivation, which counted for 30% and 28% respectively.

In the second graph, it is shown that the difference of these four factors influencing the degradation in different regions. In Oceania, it was over-grazing that ought to be responsible for the result of land dropping, as the portion was 11.3% while the total percentage of degrading land was only 13%. By contrast, the percentage of that factor was only one quarter in terms of farming land disappearing in Europe. However, over-cultivation was the crucial cause of land diminishing in North America, whose percentage was 3.3%. And the data was as twice as the over-grazing.

To sum up, over-grazing was the most major reason for farming land diminishing worldwide, but as for individual region, the portion of each cause varied a lot.