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Is agricultural productivity maxing out?

New University of Nebraska report suggests productivity gains will come more slowly than often predicted

We often hear the comment repeated that the food system will need to double its food output by the middle of this century to keep up with world demand. Are we up to it? Newly published research by University of Nebraska crop scientists raises a grim warning. They suggest the fields across the world in which almost a third of the rice, wheat and corn is raised have likely either peaked in their productivity or may actually be declining.

“Previous projections of food security are often more optimistic than what historical yield trends would support,” the researchers, Nebraska Agronomists Patricio Grassini and Kent Eskridge, write in the scientific journal Nature Communications. Many of those projections of farm productivity in the future assume the rates of gain in crop yields will compound, rather than simply grow in a straight line. But history doesn’t bear that assumption out, they believe. They challenged the assumption by testing six statistical models that are widely used in the economics literature for describing trends in crop yields over time. Using their framework to characterize past yield trends, the Nebraska researchers argue that straight-line increases are much more likely. Therefore, even though production can be expected to continue to increase, the relative rate of increase will slow over time, leaving production far below the levels the more optimistic compounded predictions suggest.

In fact, they believe, good evidence suggests crop yields have already either leveled off or actually fallen in some of the world’s major cereal-producing regions. Although their study did not specifically take on the task of predicting why those plateaus have happened, they suggest any farm will naturally face a productivity wall at some point due to limits of biology unique to the region, climate and crop.

“As farmers’ yields move up towards the yield potential threshold, it becomes more difficult to sustain further yield gain because it requires fine tuning of many different facets of management in the production system,” they write. “Such fine tuning is often difficult to achieve in farmer’s fields, and the associated marginal costs, labor requirements, risks and environmental impacts may outweigh the benefits.”

They believe that situation is now happening in the high-yield cropping systems for rice in China, Korea and Japan; wheat in the United Kingdom, France, Germany, the Netherlands, Denmark and India; and corn in Italy and France. Other factors could also be at work, they suggest, including changes in weather cycles, land degradation, a shift in where crops are produced to regions with poorer soils and climate, policies that restrict the use of fertilizers and pesticides, and reduced or poorly targeted investment in agricultural research and development.

For example, they say, ag R&D in China increased by three times from 1981 to 2000, but the rates of increase in crop yields there remained constant for wheat, actually fell relatively by 64 percent for corn and has been only negligible for rice. Similarly, in the United States, despite a 58 percent increase in both public and private investment in agricultural R&D in the United States for the same time period, the rate of increase for corn yields has only been linear, not compounded.

The overall implication? In order to keep up with expected increased demand, future grain production will require large increases in average crop yields in countries where current yield gaps are large—the countries that have the poorest access to technology, infrastructure and capital required for agricultural development. At the same time, continuing to improve the rate of gain on farms in developed nations will require adoption of technology that wrings even more productivity out of existing land, water and fertilizer. Such technology is often under attack today by opponents of modern, high-technology agriculture in the guise of such marketing schemes as "GMO-free," "natural," "antibiotic- and hormone-free" and even organic.

Most Iowa calves are born in later winter and early spring. Why?

Cold weather may seem a bad time to have baby calves, but here's why beef cattle farmers purposefully deliver them in late winter. It helps make beef more affordable for you.

Viewers of evening newscasts in the U.S. urban centers watched in horror this October as a sudden blizzard killed an estimated 3,000 cattle in Nebraska and as many as 15,500 in South Dakota. The devastation served as reminder again that "natural" farming practices like cattle ranching are often brutal and unforgiving.

Yet thousands of Nebraska beef cattle ranchers are even now preparing to enter a three-month season of trudging through the dark in rain, snow and mud to find, check and, if necessary, assist cows and their calves that are in the process of birth. For this part of the country, almost eight in every 10 calves will be born between the beginning of February and the end of May. Despite temptations to shift the all-important calving season to warmer, drier months, when the weather is not so harsh, farmers continue this traditional winter calving season. Why?

• It gives calves the chance to best use the feed Mother Nature provides—grass. Despite criticism that the modern beef farming system relies on “unnatural” feeding products like corn, the truth is nearly all beef calves raised in Nebraska and the United States spend most of their lives eating grass. Cattle farmers understand cattle are very efficient converters of grass and forage into meat, so the more opportunity they give the calves to eat grass, the more productive they are, and the cheaper it makes beef for your customers. Calves born in the late winter and early spring are being weaned from complete reliance on mother’s milk and prepared to start eating grass just as the fresh spring growth in pastures comes on strong. Ensuring those calves are ready to start grazing as soon as possible gives farmers the maximum number of months on grass to put on weight for sale by the end of the summer.

• Generally, having calves in the late winter and early spring is helpful in spreading out the work requirements on mixed family farming operations. There, farmers still rely predominantly or completely on their own labor and their family’s. Getting the high-labor tasks of calving out of the way before spring cropping season begins ensures the cow/calf enterprise doesn’t interfere with labor demands.

When are most calves born?

• It helps the mother cows, as well. Because farmers typically get only one calf out of each mother cow per year, it’s critical to their success to make sure each cow gets the full opportunity to deliver and raise that healthy calf, and then be prepared to breed for the next year’s calf. To maintain their best fertility, cows are generally given about 1.5 to two months to rest and fatten up a little before they are bred for the next year's calf. By calving in the early spring, cows can take advantage of the natural pasture growth, which is relatively high in protein in the early spring, to put some flesh back on before farmers start breeding them.

• By carefully scheduling the breeding of those cows in order to concentrate the delivery of all their calves within a narrow window of time—typically within one month, ideally—farmers produce a more uniform crop of calves that can all go to market together at the same time, improving the efficiency of the marketing system and making the entire group more attractive to buyers.

• And last but not least, many ranchers still calve at a particular time of the year because that’s how it’s always been done on their farm.

Imaginary poisoning in chicken and pork?When the U.S. Food and Drug Administration announced in late August it was finally pulling its regulatory approvals for several old feed additives used in poultry and pigs that contain traces of arsenic, the media spun the move as FDA "finally putting an end to using arsenic" in animal feed. California's largest National Public Radio beacon was typical in its reporting, proclaiming "FDA Finally Bans Most Arsenic in Chicken Feed." Bloomberg News, similarly, pronounced FDA had at last "ordered the withdrawal" of arsenic-containing products from the market. More activism-oriented web outlets repeated and amplified the news, lamenting the fact that such a dangerous poison as arsenic was still being used up until FDA's announcement.

Not exactly.

A more careful reading of FDA's own announcement here hints at the truth. The agency in fact officially refused--not agreed--on Sept. 30 to act on a four-year-old petition filed by the Center for Food Safety and the Institute for Agriculture and Trade Policy which demanded FDA revoke the decades-old approvals for the arsenic-containing compounds roxarsone, carbarsone and arsanilic acid. FDA correctly noted an inconvenient fact many of the news reports missed: Nobody was using the drugs in chickens and pigs anymore, because no company was selling them in this country.

  • The last two companies making roxarsone, Zoetis and Fleming Labs, pulled the drugs from the market voluntarily nearly two years ago, after some studies questioned whether they might be causing a level of arsenic in the meat that, although still considered safe, might be higher than the level formerly believed to result from using the additive. Rather than conduct the expensive testing required to reassure FDA of the safety of an old product, the companies instead opted to abandon the market.
  • Although the Center for Food Safety was technically correct in its contention four years ago that the three drugs were "used in 101 drugs added to feed for chickens, turkeys and pig," that statement is less a testament to the widespread presence of arsenic in animals than it is to the reality that government paperwork dies a glacially slow death. The truth is, although 101 different approvals may be written into FDA's books, none of them any longer correspond to an actual product. An analogy: The fact that 2 million 16-year-olds were licensed to drive in 1929 does not mean 2 million 100-year-olds are today careening about our streets and highways.

FDA in fact took two significant steps in August and September:

  1. It formally recognized reality, and--at the manufacturers' request--officially rescinded the license to sell the products that the companies were no longer selling and were not interested in maintaining the license on. Far from a "ban," this is a common paperwork procedure both FDA and the USDA--which regulates animal vaccines--regularly undertake at the request of the license holders. Typically, the action is to remove paperwork requirements and expense by companies no longer interested in selling products that, for one reason or another, have outlived their usefulness.
  2. FDA did, in fact, leave a single product on the market that contains roxarsone. It is used to prevent disease in baby turkeys and, although official estimates of its use are not available and the manufacturer will not say, industry experts say it is not a commonly used choice.  

Where then does that leave grocers who have to interpret this panicked food-safety string of news stories to consumers? A few points to put a little context around the reports include:

  • Although, granted, it’s not an easy sell for grocers to make, the reality reflected by reporting on arsenic in poultry, as well as the rash of reports earlier this year about arsenic levels in rice is this: Arsenic is present in a lot of food. Arsenic is a natural element present in earth’s crust, found throughout the environment—in water, air and soil. For that reason, it is inevitably found in numerous foods and beverages. Being able to detect measurable levels doesn’t necessarily say much about the source nor the risk to human health. For instance, much of the testing on arsenic levels in chickens, including the work that finally spurred roxarsone's withdrawal from the market, consistenly finds the levels are identical in chickens fed medicated feeds that contain trace arsenic compared to those never fed arsenic. Numerous common foods, as evidenced by the chart below, contain levels of arsenic vastly higher than chickens, whether fed arsenic or not.
  • Most media reports that fan the consumer attention on the word "arsenic" make no attempt to balance any minor risk of consuming arsenic from foods with the overall nutritional benefit of those foods. Just as grocers have to balance the risks of mercury in fish with the potential health benefits of consuming fish, they need to help consumers understand that giving up any particular foods because of arsenic fears are likely to actually cause more health damage than benefit in the long run.

Arsenic levels in foods

How pristine are small farms and farmers markets?

Thousands of people flock to the more than 8,000 local farmers markets around Nebraska and the rest of the country every Saturday morning. If you believe the numerous consumer surveys, they do so because they believe the produce there is higher quality, more nutritious and safer than what they could find at supermarkets. But “surprisingly little research” has really addressed the food safety practices used on small to medium-sized farms selling locally or in farmers markets, according to a team of researchers from Georgia, Virginia Tech and Clemson. So they looked into that question.

The results were not pretty.

Their study, just published in November’s Journal of Food Protection here, evaluated current food safety practices used by 226 small to medium-sized farms and 45 managers of farmers markets in Georgia, Virginia and South Carolina, based on responses to a series of mail and online surveys. The results showed:

  • More than 56 percent of the farmers used manure for fertilizer. Although manuring crops is a longstanding traditional source of plant nutrients, the important issue is that of those farmers who said they used manures (including, in one case, composted human waste), only a fraction followed what USDA’s organic standards consider the proper composting procedure to ensure those manures present no risk of contaminating produce. Disase-causing germs like E. coli O157:H7 and Salmonella have been shown to survive up to, respectively, 70 days and 159 days in manure, depending on temperatures. Proper composting of manure builds up enough heat to kill those organisms, if the process is given sufficient time: In the case of the National Organic Standards, that’s at least 120 days if the composted manure will be used on produce that directly touches the soil (like potatoes) or 90 days for crops that don’t (like strawberries). Yet, in the Journal of Food Protection study, of those farmers who use manures, one quarter waited less than 90 days before using composted manure, fully one third used raw manure or a mixture of raw and composted manure and 16 percent didn’t compost manure at all.
  • Just over half of the farmers said that farm or domestic animals—like dogs, cats, chickens and other fowl—had free access to produce-growing areas.
  • More than 27 percent of the farmers reported the water they used for irrigation had never been tested for possible contamination—16 percent didn’t test the water they used to wash produce. Although most of the farmers did test their water sources, almost a third said they used water from streams or ponds, untested well water or rainwater for irrigation. One farmer reported drawing untested surface water or rainwater to wash fruits and vegetables.
  • In 43 percent of the farms, farmers reported they do not sanitize surfaces that touch produce at the farm, and only 33 percent of farmers always cleaned their transport containers between uses. Of those who cleaned containers, 46 percent used water and detergent; however, responses included a variety of methods including bleach and water, soapy vinegar water, and rain and sun.
  • Although half of the surveyed farms said their crops are harvested by workers with their bare hands, only two out of three said they made bathroom and hand-washing facilities available near the fields or packing sheds.
  • Only 41 percent said they had given their workers any kind of sanitation training when harvesting, cleaning or packing crops.

Once those crops reach the farmers market, the study showed, sanitation conditions don’t improve much.

  • Responses from market managers indicated that over 42 percent have no food safety standards in place for the market.
  • Most market managers reported that they do not ask farmers questions about how the products are grown or handled before they are brought to market. Only from 2 percent to 11 percent asked, depending on the practice they were asking about.
  • Of the 45 market managers responding, only a little more than half provided hand washing facilities for workers and vendors in the market.
  • Less than one fourth of the farmers markets sanitized their surfaces and only 11 percent always cleaned market containers between uses.
  • Over 75 percent of the market managers offered no sanitation training to their workers or vendors, even though 27 percent allowed on-site food preparation. Many markets also allowed sampling of products but offered no training for vendors on how to do this safely.
  • More than half of the managers said no cooling methods were used in their markets. For the other half, a variety of cooling methods were identified , with the most common method, at 49 percent, being the use of portable picnic coolers with ice. This method raises concerns about the safety of the water used in making ice and also in the sanitary handling of it in an outdoor market, the researchers noted.

Worry about Zilmax?When Tyson Foods, the nation's largest meat processor which buys roughly a quarter of all beef cattle, announced it plans to suspend buying cattle next month that have been fed the short-term feed additive Zilmax, it raised the potential for yet another round of questions from your beef shoppers about this "growth hormone." Here a few points to help you answer their questions:

  • Zilpaterol, the active ingredient in Zilmax, is not a growth hormone in the same sense as the other steroid-type hormones that have been used in cattle for decades. Zilpaterol is more correctly categorized as a "growth enhancer," which is of the category known as "beta-agonists." Beta-agonists work by signaling the animal's body to devote a greater portion of the energy derived from feed to growing muscle rather than fat, which in effect increases the amount of meat produced given the same amount of feed.
  • It's important to clearly understand Tyson has raised no food-safety concerns about the additive, which the product's maker, Merck Animal Health, was quick to confirm. "Zilmax has a 30+ year history of research and development and rigorous testing," the company said in a prepared statement. "Worldwide regulatory agencies have reviewed extensive data on Zilmax and have concluded that use of Zilmax according to the label is safe in cattle."
  • Tyson's complaint about the additive, which it informed cattle feeders of by personal letter, was that unnamed "animal scientists" have raised concern about a possible connection between its use and the ability of animals to walk when they arrive at the processing plant. The company said it was suspending purchases in the interest of precaution, until the question could be settled. Merck also disagrees with the animal welfare claims Tyson has raised. "We are surprised by Tyson’s letter. We are confident that, based on all of the available data on Zilmax, the experience reported by Tyson is not attributable to Zilmax. Indeed, Tyson itself points to the fact that there are other possible causes and that it does not know the specific cause of the issues it recently experienced."
  • In an online essay, medical doctor Richard Raymond, a former USDA undersecretary for food safety, succinctly summarizes the safety of beta agonists in general, including zilpaterol. He writes here:
    • Although Zilmax has been on the market in the U.S. just since early 2007, beta-agonists have been used in U.S. pork production since 1999 and in US cattle production since 2003. They are also approved for use in turkeys, although not widely used.
    • More than two dozen countries around the world also approve beta-agonists for use in food animals.
    • Beta-agonists are a particularly safe additive, he says, because they are broken down and excreted from the animal's system quickly, leaving little or no residue in the meat. For the most part, they are never detected in meat sampled by USDA; when a rare positive does pop up, it is far below the maximum residue level set for human safety by FDA.
    • Beta-agonists have been used and studied in human medicine for decades. They are commonly used in young children via inhaler to treat asthma attacks and in pregnant women to prevent premature labor and protect unborn babies. "If we give them in significant doses to our most vulnerable patients, including young children, pregnant women and their unborn babies, most people would agree then that it is safe to consume meat from animals supplemented with beta-agonists when it is basically undetectable," Raymond argues.

Partners

In patnership with the Nebraska Grocery Industry Association

The Nebraska Grocery Industry Association was formed in 1903 by a group of Omaha grocery store owners, wholesalers and vendors to allow them to promote independent food merchants and members of the food industry, and to promote education and cooperation among its membership. NGIA continues to represent grocery store owners and operators, along with wholesalers and vendors located throughout Nebraska, by promoting their success through proactive government relations, innovative solutions and quality services. NGIA offers efficient and economical programs. NGIA also lobbies on both a state and national level, ensuring that the voice of the food industry in Nebraska is heard by our representatives.


Supported by the Nebraska Farm Bureau

The farm and ranch families represented by Nebraska Farm Bureau are proud sponsors of the Farmer Goes to Market program. We take great pride in supporting Nebraska's agricultural foundation. A key part of that effort is to make sure we produce safe and affordable food. This newsletter is an important part of our effort to connect the two most important parts of the food chain -- the farmer and the grocer -- with the goal of increasing consumer awareness and information about how their food is raised in Nebraska.


Supported by the Nebraska Corn Board

The Nebraska Corn Board, on behalf of 23,000 corn farmers in Nebraska, invests in market development, research, promotion and education of corn and value-added products. The board aims to work closely with the farmer-to-consumer food chain, to educate everyone about the role corn has in our everyday healthy lives. The Nebraska Corn Board is proud to sponsor the Farmer Goes to Market program to help bring its mission of expanding demand and value of Nebraska corn to the consumer, through the strongest touch point in that chain: the Nebraska retail grocer.


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