Deforestation has an alarming affect on

Deforestation is the phenomenon of the removal of forests i.e. trees.
Removal of trees causes global warming, a temperature rise, and ultimately natural calamities like floods and droughts. The flood causes the wash off of the top fertile layer of soil from the agricultural field which is called soil erosion, which makes the soil unfertile and lacks nutrients.
Thus, deforestation has an alarming effect on soil erosion which makes the soil unfertile.