IELTS Task 1. IELTS 8. Could you please correct my notes? Please help me kindly.

The pie chart illustrates the causes of degeneration in agricultural lands, while the table compares three territories where there are swayed by those degradation factors in the 1990s.
As the first chart demonstrates, the underlying cause of land degradation is due to over-grazing by cattle which (accounts for about 35% of overall degredation) is about 35%. Deforestation comes next (accounting for) with correct again just not "academically native" approximately 30%. In contrast, over-cultivation accounts for only 20% of overall land degradation.
As can be clearly seen from the table, Europe had the highest percentage of land degradation at around 23%, while just 5% of North America was affected by land degradation during 1990s. Additionally, Oceania was affected by just 30% of total land degradation.
Furthermore, the important (primary--is it the number one cause? if so primary sounds better) cause of land degradation in North America was due to (the) over-cultivation by (of) crops which is (accounted for) about 3.3%, while in Europe and Oceania, deforestation and over-grazing had the most crucial role in land degradation with (accounting for) 9.8% and 11.3% respectively.

This is much better than our high schools produce amongst native speakers, good job! I just polished it to sound more academic.

IELTS Task 1. IELTS 8. Could you please correct my notes? Please help me kindly.

The pie chart illustrates the causes of degeneration in agricultural lands, while the table compares three territories where they there are swayed by those degradation factors in the 1990s.
As the first chart demonstrates, the underlying cause of land degradation is due to over-grazing by cattle which is about 35%. Deforestation comes next with approximately 30%. In contrast, over-cultivation accounts for only 20% of overall land degradation.
As can be clearly seen from the table, Europe had the highest percentage of land degradation at around 23%, while just 5% of North America was affected by land degradation during 1990s. Additionally, Oceania was affected by just 30% of total land degradation.
Furthermore, the important cause of land degradation in North America was due to over-cultivation by crops which is about 3.3%, while in Europe and Oceania, deforestation and over-grazing had the most crucial role in land degradation with 9.8% and 11.3% respectively.

Only correction was a small typo you made. The rest looks fine to me!