Plural of "terres"

Question

Great exercise! This wonderful description of Le volcan de la Reunion reminds me of when I lived and worked in Guatemala - a magical and beautiful country with many volcanoes. Every evening, we could see the active volcanoes burning and glowing against the night sky. Like I said, magical!

I just want to ask why "nouvelles terres" is plural. Of course, I am familiar with "la terre" meaning "the earth". When I researched the meaning of "une terre" (as opposed to "la terre"), the translation given was "land". So, I wrote "quarante-cinq hectares de nouvelle terre". Which I take it would mean: "45 hectares of new land". Is this incorrect or are both variations, correct?

Merci et Bonne Continuation !

P.S. Took a break for several weeks, (for personal reasons), but glad to be back. Love this community of positive and supportive learners!

Accepted Answer

Bonjour N. Hilary,
Here "terres" is in the plural form as it represents an area of land. If you are referring to the soil/ground itself, then it is usually singular. 
See example below:

trente hectares de terre = thirty acres of land -> the soil / ground
trente hectares de terres = thirty acres of land -> the cultivated land / an area of land

La terre de chez nous est aride = Our soil is arid -> the soil / ground
Il vit sur ses terres = He lives on his land -> the cultivated land / an area of land

I hope this is helpful.
Bonne journée !