By Nick Miles The BBC's Central American Correspondent

Plans for a second international airport to service Mexico City are on stand-by after a series of court rulings that have put the project's future in doubt.

They need this land - it's a matter of survival

Jesus Espinosa, head of the farmers' movement

The site for the multi-billion dollar airport was announced by the government at the end of last year.

It ordered the expropriation of farm land around Texcoco, 30 Km east of the capital.

But farmers in the area say they will not accept the government's compulsory purchase order on their lands. They have taken to the streets in protest and have won a number of decisions in the lower courts on the grounds that the expropriations are anti-constitutional.

Rural traditions

In the early morning sun, hundreds of smallholder farmers are out in their maize fields tending their crops. Horses pull carts laden with ripened corn, and sheep are herded along rutted dusty roads.

It is a scene reminiscent of the 19th Century, in a country that over the last two decades has undergone some of the most rapid industrialisation in the world.

Our land is not for sale and we will never give it up

Alejandro Portillo

The plots of land at Texcoco are too small to sustain a whole family. They were distributed to landless farmers after the end of the Mexican Revolution 90 years ago, and have been divided and sub-divided between family members every since.

This does little to dampen the strong feelings held by the farmers about their land.

"The crops we grow here supplement the poverty level wages people receive in factory jobs or as street sellers in the informal economy," said Jesus Espinosa, head of the local farmers' movement around Texcoco. "They need this land - it's a matter of survival."

Farmers' protest

Just half an hour's drive away, in the capital of the state of Mexico, Toluca, hundreds of protesters are clambering over a vast statue of Emiliano Zapata, the Mexican revolutionary hero who championed the cause of millions of landless farmers at the beginning of the last century.

"Zapata lives, the struggle goes on," yells the crowd, machetes held aloft in salute to their hero.

"I've come here to tell the government that our land is not for sale and we will never give it up," said Alejandro Portillo, his face shaded from the sun by a wide brimmed straw hat.

"The government will have to fight us and step over our bodies if it wants to take the land," added Alejandro Garcia, whose grandfather first worked his five-hectare plot after the land distributions of the 1920s.

Emiliano Zapata championed the cause of landless farmers

But it is not just the power of protest that seems to be in the farmers' favour. After a number of court rulings cast doubt over the legality of the expropriations, there is a growing confidence amongst the farmers and those representing them that the airport may be delayed indefinitely.

"It is obvious that the government is on shaky ground here," said Ignacio Orihuela, a constitutional lawyer working for the farmers.

"If it wants to expropriate the land, the government has to prove there is a pressing need for the new airport now. But air transport experts say [the old site] has a good 20 years useful life left in it."

Government undaunted

It is an embarrassing and potentially costly situation for President Vicente Fox, but government ministers remain steadfast in their will to push ahead.

"The new airport will provide jobs for thousands of people. Mexico can't survive without good transport links," said the director of airports at the Mexican transport ministry, Ernesto Velasco.

"I sympathise with the farmers of Texcoco but there's no way such an important new project should be held up by a few dissenting voices at the expense of the vast majority of Mexicans who are in favour."

The coming months will be a testing time for the government. If the supreme court upholds the constitutional challenges being put before it, then it could spell more problems across Mexico for future development projects - like the government's much vaunted Puebla Panama plan that aims to build billions of dollars' worth of new roads across the south of the country.

With the battle lines drawn, the outcome will be watched closely by rural groups across Mexico and the rest of the world.