soil fertility
Technical term used in agriculture, environmental science, and related fields.
We use organic fertilizer to maintain soil fertility.
The soil fertility in this region is declining year by year.
地力 refers to the inherent productive capacity of soil, often used in agricultural contexts, while 土壌肥沃度 is a more technical term specifically for soil fertility.
Compound of 土壌 (soil) + 肥沃 (fertile) + 度 (degree). The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning.