Ler reproduce infrequently, generally becoming fertile only every ten years.

After the last ice age it became more fertile, then dried up again.

Water is getting percolated and land becoming more fertile and people are taking more crops than before.

So that this which is desert shall once more become fertile.

Soil was becoming less fertile and worn out.

It may take approximately five years before becoming fertile.

In the plains to the south of the base, a gentle but ineluctable transformation was being wrought, as the barren yellow fields became fertile and grew.

Opportunistic breeders are typically capable of breeding at any time or becoming fertile within a short period of time.

With the decrease in water and the high demands for agriculture, Southern African's land is becoming less fertile.

Gordon Merrick broke new ground that has only recently become fertile.