огромное непаханое поле. inf.

[TatyanaUs]

В сфере развития инфраструктуры - огромное непаханое поле.

[upahill]

infrastructure has a tremendous room for growth

consider:

...

[sledopyt]

+ options:

The sky is the limit when it comes to infrastructure development opportunities.

Infrastructure development offers immeasurable opportunities.

(The field of) infrastructure development holds tremendous promise.

[leha]

Контексту бы побольше. А то можно предложить и "The input in the infrastructure development is next to none" :).

[silly.wizard]

+
... lots of stones (to turn/yet to be turned) (on/in) the field of infrastructure development. ;)

not sure about (in/on)

[SirReal]

Oh brother, turn thee thy stones on the field... :)

There's a lot of work to be done in developing the infrastructure (of ?).

[Tamerlane]

there is a vast untilled field

также

vast unplowed (unploughed) field

[Oo]

a vast undeveloped field