On Jan. 31, a mass of arctic air moved into New Mexico, bringing snow and several days of record sub-freezing temperatures. Electric power was in short supply, pipes froze, gas service was interrupted, many schools and government offices were closed and transportation was disrupted.

The "2011 Groundhog Day Blizzard" came early to New Mexico but the effects on the state's agriculture sector may linger for months or even years. The precise extent of the plant and crop damage caused by the prolonged cold temperatures is far from certain at this point, but New Mexico State University experts predict that they will be variable and, in some cases, potentially serious, depending on the crop, the region, and individual circumstances.

New Mexico State University's Agricultural Experiment Station has 13 agricultural science centers around the state, 10 of which are outside Dona Ana County. In many cases, NMSU researchers have first-hand knowledge of the effects of the freeze because it affected the plants they are growing. In addition, the Cooperative Extension Service has an office in every county and Extension agents are in touch with local producers, researchers and each other.

One thing all the experts seem to agree on is that it is still too early to know very much about many of the plants. Below are a few tentative conclusions.

The Las Cruces area was experiencing a string of 70-degree days recently as Stephanie Walker, a vegetable specialist, headed out to assess some onion fields. She was concerned about lettuce, as well. "Although the fall-seeded onions sustained damage, most were not killed outright," she said after her site visits. "We could experience more bolting than usual in the onion crop because of the temperature extremes."

Walker speculated that some onion farmers might replant their onion fields with a different crop. One possibility, especially with the current market, is certainly cotton. She also reported some lettuce was lost but that most of it was fine.

Tracey Carrillo, superintendent of NMSU's Leyendecker Plant Science Center and Fabian Garcia Research Center in the Las Cruces area, predicted that most of their large year-old seed onions would survive.

Nut crops

Pecans are a major crop in the Mesilla Valley around Las Cruces. Richard Heerema, NMSU's pecan specialist, said the varieties typically grown here are able to withstand very cold temperatures and should have been fully dormant prior to the freeze. He thinks mature and well-maintained trees sustained little or no damage. Unhealthy trees and very young trees would be more susceptible to frost damage.

Pistachios grown in Dona Ana and Otero counties may have sustained more damage than pecans, Heerema said. Temperatures below 10 degrees Fahrenheit can pose a threat to these trees. He suggested that owners scrape the bark on last year's growth with a knife or even a thumbnail to check for brown cambium, an indication of damage. "We won't really know the extent of any damage until spring growth begins," he said.

Woods Houghton is an Extension agent in Eddy County in the southeastern part of the state. He has expressed concern that most trees in his area may have sustained damage that will become evident over the next few years. He fears that the mild late fall and early winter resulted in trees that weren't fully dormant and that the prolonged very low temperatures in his area may have caused intracellular ice crystals that ruptured tissue cell membranes.

Houghton has seen some damage to fall-planted alfalfa and wheat in his area but said it is still too early to know the extent of the damage. He stressed that alfalfa is grown in many places around the world where bitterly cold temperatures are normal. In a recent article he wrote for the Carlsbad Current-Argus, he discussed his concerns about alfalfa and suggested how farmers might eventually deal with fields where productivity seems doubtful.

Mark Marsalis is an Extension agronomy specialist at NMSU's Agricultural Science Center at Clovis. He said it is really too early to accurately assess the damage to winter wheat, but that "wheat is very resilient to cold temperatures at this stage of growth." He suspects that, due to dryness, there may well be some death in the dryland wheat grown in the region and that the dry conditions will likely play a larger role in crop death than the freezing temperatures. It may be early in the spring before the full extent of damage is known.

"The late-planted non-irrigated wheat that wasn't tillered very well is the most susceptible to freeze damage," he said. "The irrigated fields where some soil moisture was present should be in much better shape." The fields he has inspected so far have only shown moderate to severe leaf burn damage and should recover if water does not become the limiting factor.

Sangu Angadi is a crop physiologist, also based at the Clovis center, whose research focuses on oilseed plants. He agreed that it is too early to assess damage accurately and completely, but he supplied a few photos of dead plants from his test plots. He reported that most of the more than 50 varieties of winter canola he is studying seemed to survive well in the test plots planted relatively early (mid-September), while the mid-October planting was nearly wiped out. While many leaves were visibly damaged in the September crop, the crowns of the plants tended to still be green.

Angadi said almost all of the winter safflower plants were killed off. They were part of a project, headed by Texas Tech University colleague Dick Auld, to develop varieties of winter safflower that will do well in the Southern Great Plains area. "If any breeding material survives this cold, it will be great news for us," he said.

Forage update

Leonard Lauriault is a forage agronomist at NMSU's Agricultural Science Center at Tucumcari, slightly northwest of Clovis. He reported that soil temperatures only dropped to 24 degrees Fahrenheit in his area, where there was some insulating snow cover. He thinks alfalfa in most of the state is less susceptible to cold than in some other areas because the winters tend to be dry and the soil tends to be more alkaline and high in potassium.

Rick Arnold, a weed science expert and superintendent of the Agricultural Science Center at Farmington in the far northwest corner of the state, predicts the alfalfa and winter wheat grown there will be fine but the fate of winter canola is less certain. Their region is more used to extreme cold than many other parts of the state, though, so the varieties farmers choose are probably better suited to survive extreme cold.

Arnold's colleague Kevin Lombard is a horticulture specialist at the Farmington science center. He reported all of the grape vines he checked after the storm had at least survived. A later random check of his vines suggested minimal damage; he was finding a lot of green cambium. He said a hard freeze in late spring is typically more of a threat to grapes than mid-winter cold. And he echoed what most other experts have said, that it is too early to assess much of the potential damage to established plants, including grapes and fruit trees. "I'll know more this spring when bud break occurs," he said.

Shengrui Yao is a fruit specialist based at the Sustainable Agriculture Science Center at Alcalde, north of Santa Fe near the Rio Grande. She reported that the peach flower buds both there, where the temperature dropped to -11.3 degrees Fahrenheit, and at the Agricultural Science Center at Los Lunas south of Albuquerque, were badly damaged by the freeze. The evidence includes the brown/black color of the buds she discovered when she cut them open. She said apricots were also damaged, but not as badly as peaches and that "flower bud survival of sweet cherries and tart cherries is much better than peaches." Apple buds seem to have escaped damage from this storm. Yao recommends that growers check their flower buds before pruning or do the pruning late when the season starts.

Yao is also involved in research on berries and reported the freeze probably caused some cane damage to blackberries.

Will the intense early February cold spell help reduce the populations of insect pests? Tess Grasswitz, an integrated pest management specialist based at the Agricultural Science Center at Los Lunas, said, "It's anybody's guess. What tends to knock them back the most is not one or two short periods of intense cold, but cycles of cold alternating with significant warming. They become active during the latter periods and start to metabolize stored fat. If that happens often enough, then they have fewer reserves to get them through any subsequent cold snaps."

Is there good news? It seems clear that things could have been worse. And the timing of the storm was obviously beneficial to some of the state's crops, such as chili peppers and cotton, which have not yet been planted.

For expert guidance on local crop issues, check with the NMSU Cooperative Extension Service office in your county. For a list of offices and for contact information, go to http://aces.nmsu.edu/county/