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New Mexico State University

New Mexico State University

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NMSU Researchers Cultivate Weeds

LAS CRUCES - Meticulous New Mexico homeowners squat and pull weeds for hours. While they dream of winning the "best lawn in the neighborhood" award, some researchers at New Mexico State University actually spend their summers growing weeds.


To study how best to rid weeds from the Southwest, scientists like Jill Schroeder with NMSU's Agricultural Experiment Station (AES) must first grow a healthy crop of invaders. With the care gardeners give their rosebushes, weed scientists nurture their weeds.

At the Leyendecker Plant Science Center in Las Cruces, Schroeder and NMSU student workers plant weed seeds collected from across the nation in small, fiberglass-framed, circular plots. Researchers water, fertilize, talk to and even weed their weeds. "It can be a real headache to get the weeds to grow, Schroeder says. "Sometimes we have to baby them along."

Tender loving care is necessary because weeds are more than just nuisances for homeowners. To New Mexico's farmers, weeds like purple nuts edge, London rocket and cotton weed can mean devastated yields and profits. Even when farmers can quickly diagnose the invader, there's no easy answer to managing weeds in the Southwest. What's lacking is a good base of information about how the weeds grow and how herbicides act in arid lands.

"There is very little information about how herbicides behave in the arid Southwest with furrow irrigation systems," Schroeder says. "Most studies are done where the land is irrigated by sprinklers or rain."

Companies primarily register herbicides for use on major crops such as corn and soybeans in bigger production areas with higher rainfall. They often don't do the testing required to register use on a crop like chile, which is considered minor nationally. This leaves Southwestern farmers without many tools for weed control. Their woes are compounded because weeds use precious water supplies that should go to crops.

"We need to use weed management practices that will sustain soil and water resources and also economically sustain the farming community," Schroeder says. "We need to make sure that the herbicides we use are effective against the weeds we have in New Mexico and that they don't injure our crop, variaties.

The first step, she says, is learning as much as possible about the weeds how they grow, adapt to conditions and interact with their environment. For her research, Schroeder needs to grow healthy, uniform weeds. But the weeds don't always cooperate. "Sometimes they grow everywhere except in your test plot," she says.

Weed seeds don't all germinate at the same time, which ensures their survival in the wild. That makes it hard to study a whole crop at once. Schroeder often goes to great lengths to get seeds to germinate uniformly. She may treat the seeds with acid or bleach or actually poke them individually with pins. These techniques break down seed coats, so the seeds can take an water better and germinate faster. During the winter, Schroeder works in the greenhouse, trying to find out what works to make particular weeds germinate. By the time summer arrives, she's ready to take her work outside.

one common broadleaf weed under Schroeder's scrutiny is cotton weed, which reeks havoc on chile and cotton crops. She planted cotton weed seeds from Colorado, Mississippi, North Carolina, as well as New Mexico, to see if they have different characteristics and to find out how the plant has adapted to different environments. "We've found that cotton weed really likes the Southwest," she says.

Schroeder also is working with Steve Thomas, a nematologist, and Leigh Murray, an experimental statistician, to study the interaction between cotton weed and nematodes on chile. "We want to see how the weeds and nematodes coexist, so down the road we can find strategies to manage them," she says.

The key to future weed management research, Schroeder adds, is studying the problem as part of a system with insect and disease control. Scientists from different disciplines must work together. "Because we grow a lot of crops on a limited irrigated area, we need careful management so we don't waste our resources."