desertification的動詞形式是啥

動詞是desert，例如：

1、Somalia is mostly desert.索馬里大部分地區都是荒漠。

2、He also wants to use the water to irrigate barren desert land.他也想用這些水灌溉荒漠。

3、Food desert refers to an area where fresh food is either non-existent or too expensive.“食品荒漠”是指沒有新鮮食品或這種食品價格極貴的地區。看了以上定義，你也許對此還是沒啥概念。憋急！