"expanse of fields" is correct and usable in written English.
It can be used to describe a large area of open land, typically covered by crops. For example, "As I drove down the long road, I was amazed at the expanse of fields that spread before me."
Irrigation ditches channel water from pump houses out into the flat expanse of fields.
Madina's grave lies at the edge of a municipal graveyard, on the bleak outskirts of the border town where she spent her last afternoon, on the edge of a vast, flat expanse of fields.
His votes, tallied up in chalk on a garage door, are still on display.The last collectiveNow in full command of the village, Mr Zhang has the task of untangling one of the knottiest problems left by Mr Yan the fate of Beihe's malt factory, whose dour concrete façade dominates the village skyline of closely clustered houses surrounded by an expanse of fields.
The 450-m transect of groundwater and sediment properties obtained in Araihazar extends from the bank of the Old Brahmaputra River, through Balia Para village, and ends in a low-lying expanse of fields located in the partially filled channel of a former river (Fig. 2b).
Every restaurant, every hotel, every car, every person walking is a speck in the expanse of fields, mountains, miles of crashing ocean surf.
Not only did five of the nine fairways cross each other, they did so all in one great expanse of field which was formerly the Fort Jay parade grounds.
Pickets of cypress and walls of boxwood clipped into oblongs capped with half-globes lead the eye down a series of "rooms" into the untamed expanse of field and mountain.
In the expanse of field beyond, a trio of mine-clearers prodded the earth with poles; power lines above had rendered their antiquated sensors useless – a predictable headache for the men of Ukraine's ramshackle army.
Their position fringes no-man's land, an overgrown expanse of field littered with mines and unexploded munitions.
Under soaring skies were great expanses of fields -- some empty except for a solitary tree, others lushly rowed in grape vines -- surrounded by layers of rolling hills with puffs of clouds billowing from behind them.
It may be the arresting landscape: expanses of field and forest, laid out by Frederick Law Olmsted, against a spectacular panorama of the Green and Adirondack Mountains and the glittering giant between them, Lake Champlain.
