Nearly 27% of Roundup Ready alfalfa growers surveyed felt the crop produced higher yields than conventional varieties while nearly 12% said the transgenic varieties yielded less. More than 50% of surveyed growers felt yields were the same whether the crop was transgenic or not and about 11% didn’t know one way or the other.
The weed-free alfalfa seedling plots were treated with Roundup alone and in combination with other herbicides at the Intermountain Research and Extension Center in Tulelake, CA. Weedy strips are untreated control plots.
Of the Roundup Ready alfalfa growers who answered a University of California survey on the genetically engineered crop, 72% said they’d plant it again. Another 21% said they might, while 7% said they wouldn’t.
Better weed control was the top-ranked answer to the question of what they liked most about Roundup Ready alfalfa and the cost of the seed was the major negative. Most growers were more concerned about the potential for Roundup-resistant weeds than about potential contamination of conventional alfalfa by the transgenic crop.
“We wanted to get a sense for how growers currently feel about Roundup Ready alfalfa, its potential role and whether Roundup Ready alfalfa could coexist with conventional alfalfa,” said Steve Orloff, the Siskiyou County, CA, farm advisor who authored the survey with University of California Extension forage specialist Dan Putnam.
A total of 381 growers took the voluntary survey, conducted via the Internet last fall. Orloff said it likely overrepresented organic, export and Western growers and underrepresented areas including the Northeast and parts of the Midwest. Of the total respondents, 113 indicated that they had grown the transgenic legume and were directed to answer a dozen additional questions on it.
The farm advisor reported on Roundup Ready alfalfa growers’ answers to those questions in a presentation at the Western Alfalfa & Forage Conference, held Dec. 11-13 in Las Vegas, NV.
“About 25 respondents felt that the performance (of Roundup Ready alfalfa) far exceeded expectations; 60 were very pleased with the result,” Orloff told the 800-plus conference participants. “Around 18 were satisfied, eight growers were disappointed and two were extremely disappointed. The reason those growers were extremely disappointed was because the weed control was not what they expected. And they felt that the Roundup Ready varieties yield a little bit less.”
Sixty-three percent of those who’d grown the transgenic crop cited better weed control as an advantage; nearly 49% also liked its weed management simplicity; 37%, flexibility in application timing; and 24%, higher yields, quality or stand persistence of Roundup Ready alfalfa. They were asked to choose up to two answers to that question – and to the question asking what they liked least about Roundup Ready alfalfa.
Nearly 17% of growers didn’t feel there were any negatives to the crop. A total of 77% didn’t like the cost of the crop’s seed; 19%, Roundup-resistant weeds; 15%, the technology-use agreement; 12%, that varieties didn’t seem to yield well; 4%, that weed control wasn’t effective; and 5%, the difficulties of marketing Roundup Ready alfalfa.
“Apparently, marketing the transgenic crop hasn’t been a very big issue for most growers,” Orloff said.
In another question, asking if growers are concerned about the possibility of Roundup-resistant weeds in their fields, about 41% said they were concerned, 34% were not sure, and 25% said they weren’t concerned.
“So I think word is getting out … that this is something we need to worry about. We need to develop a weed-management program for Roundup Ready alfalfa to help put off or prevent the evolution of Roundup-resistant weeds.”
Growers were also asked whether they were using or planning to use any weed-resistance prevention practices. As the following percentages show, some growers indicated that they used – or plan to use – more than one method.
“The most popular answer was rotating herbicides (47%),” Orloff said. “Next was rotating to non-Roundup Ready crops after alfalfa (36%), and the next most popular answer was carefully monitoring the weeds that escape Roundup (32%).” Just more than 22% said they were tankmixing herbicides and just 10% were spraying only Roundup on alfalfa.
Nearly 27% of Roundup Ready alfalfa growers felt the crop produced higher yields than conventional varieties while nearly 12% said the transgenic varieties yielded less. More than 50% of growers felt yields were the same whether the crop was transgenic or not and about 11% didn’t know one way or the other.
“We’ve done trials in California to try to get at this issue of yield potential of Roundup Ready vs. conventional varieties,” Orloff said. Because of the way the crop was genetically modified and deregulated, it wasn’t possible to compare the same conventional and Roundup Ready varieties. But the study showed both types of varieties, at different dormancies, could yield similarly – or not.
“There are high-performing Roundup Ready varieties and there are high-performing conventional varieties. The key is to look, just as you do with any variety, for the highest-yielding variety. Not all Roundup Ready varieties yield the same.”
Half the grower-respondents thought the quality of alfalfa harvested from transgenic and conventional varieties was the same, but 41% said they definitely gained a higher-quality product from Roundup Ready alfalfa. Seven percent said they didn’t know while more than 2% said the quality was lower in the transgenic crop than in non-Roundup Ready alfalfa.
“If you have a Roundup Ready field, you may have higher quality in that field because you had better weed control,” Orloff pointed out. “We want to look at the genetic potential of the two types of varieties and if there’s any difference in their inherent forage quality.”
In one field study he took samples and compared quality values for crude protein, ADF, NDF and TDN calculated from ADF. “We had 10 Roundup Ready varieties and 22 conventional varieties and, on average, they were about as close to identical (in quality) as you could get.”
Growers were also asked whether the biotech crop offered better stand persistence. About 49% answered yes while 36% felt it was the same as with conventional. Just about 4% thought Roundup Ready alfalfa provided lower stand persistence and nearly 12% didn’t know.
“In the survey, cost-effectiveness was the least-popular response to the advantages of Roundup Ready alfalfa. The cost-effectiveness of the Roundup Ready system is extremely difficult to quantify because it depends on your area and your weed pressure. But I think, in the long run, it has to be cost-effective or it wouldn’t continue,” he said.
The base gene-tics of conventional vs. transgenic varieties cost about the same, so the primary cost difference is in the technology fee ($150 west and $125 east of the Rockies) per 50-lb bag of Roundup Ready alfalfa. At a 20-lb/acre seeding rate, that equates to a $60/acre increase to plant Roundup Ready alfalfa in the West.
“But the herbicide cost for glyphosate nowadays is … significantly less than $10/acre. Compare that with conventional herbicides: For seedling alfalfa we’re typically spending between $30 and $45/acre; for established alfalfa, between $25 and $40. So you can see there are pretty significant savings, but that depends on the number of Roundup applications you’re going to have.
“There are considerable incentives for growers to recoup those higher upfront costs of the seed as quickly as they can, so they may want to use glyphosate alone. Here again, we strongly encourage growers to incorporate other herbicides into that rotation. You don’t want to use just glyphosate alone again and again.”