By Ken Bensinger | Contributor to The Christian Science Monitor

CHAPARROSAS, MEXICO - In dirty jeans and a ragged ballcap, Jose Santiago stands outside the cinderblock shed he shares with 42 people he barely knows. He's 550 miles from home.

Mr. Santiago and the others came to this rural corner of the north-central state of Zacatecas to do what nobody from Chaparrosas would: pick the spicy red chili peppers that blanket the fields around town. That's because nearly every able-bodied worker from here - and most of the state for that matter - is living in the US.

Upwards of 1 million Mexicans are successfully crossing into the US each year, leaving behind a dearth of laborers. Increasingly, that void is being filled by people like Santiago - poor Indians from remote villages throughout Mexico. This is the other side of the US immigration equation, the second internal wave of Mexican migration necessitated by the exodus across the Rio Grande. All around the country, villages, small cities, and even entire states are seeing the cultural landscape shift under their feet as internal migration shows every sign of increasing.

"Our workforce has left," says Tomas Torres, the general secretary of Zacatecas. "So these other people come here, lured by the high demand for seasonal labor. But then they decide to stay."

In no part of Mexico is this situation more evident than in Zacatecas. It has the highest per-capita emigration rate of any Mexican state - an astounding 1 of every 2 Zacatecans are estimated to reside in the US. That opens the door to migrants who come from poor Indian towns in states like Veracruz, Hidalgo Durango, Jalisco, and San Luis Potosi.

The homegrown labor shortage has forced Zacatecas farmers to increase the wages they pay people to pick the state's abundant bean, onion, garlic, tomato, and chile crops. Today the average rate is 100 pesos a day, according to Mr. Torres, or just under $9, more than double the country's minimum wage, which is standard for field workers in the rest of Mexico.

Farm owners send recruiters in flatbed trucks to round up workers, and promise high wages via ads on rural radio stations. It was one of those radio spots that convinced Concepcion Flores to travel about 400 miles with her husband and infant child to Chaparrosas. "It said they'd pay you and give you good food," says Ms. Flores, whose husband works the fields. "We make more money here. Life is better."

Here in Chaparrosas, workers are welcome and generally unobtrusive. But elsewhere in Zacatecas, it's a different story. "In the last six years, many more people have come from other states to work here," says Laura Macias, a radio reporter in Tlatenango, in the fertile south of Zacatecas. "They come to work, but they stay and cause problems."

According to Ms. Macias, the laborers, largely Huichol Indians from neighboring states Jalisco and Nayarit, have increasingly been accused of thefts, assaults, and even murders in the normally quiet community. The accusations have led to hard feelings toward the newcomers, and tensions in Tlaltenango are on the rise. But, Macias admits, it's proven hard to link crimes directly to any of the Huichols, and she wonders if part of the problem isn't that "locals are resentful that outsiders are earning money in their town."

In addition to suspicion and jealousy , new arrivals often face substandard living conditions and exploitation from farmers. "A lot of people around here want to take advantage of them, and they'll offer them below the current rate," says Alfonso Lara, a garlic and onion farmer in Calera, one of the state's key agricultural hubs. He says farmers lure workers with offers of housing, food, free transport, and wages above anything they can find back home.

But the housing is typically a cement or dirt floor in a fruit warehouse, and the food is meager. Moreover, the farmers typically don't pay the workers until their contract is finished and often deduct hidden expenses on payday.

Then there's the culture shock. "These people are trading in their traditional Indian clothing for Nike tennis shoes and Yankees hats," says Torres. "Sometimes they arrive and they don't even speak Spanish. And they end up begging in the streets."

For the state's new governor, Amalia Garcia, the challenge is "to make sure Zacatecans aren't so desperate to leave" for the US. Ms. Garcia says she'll do that by creating more and better jobs, mainly in manufacturing.

But she admits it's hard to imagine Zacatecans returning to the fields having tasted higher wages on the far side of the Rio Grande. Which means that people like Santiago will continue to be drawn to the state's farmlands. "I like it here," says Santiago, who clears $6 a day, most of which he sends home to his wife and two children in Veracruz. "I have almost everything I need."