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Published August 18, 2014, 10:37 AM

Reducing postharvest loss

With all the effort it takes to grow a food crop from seed to sale, it might be surprising that some farms in Brazil lose 10 to 12 percent of their yield at various points along the postharvest route.

By: Debra Levey Larson, Agweek

URBANA, Ill. — With all the effort it takes to grow a food crop from seed to sale, it might be surprising that some farms in Brazil lose 10 to 12 percent of their yield at various points along the postharvest route.

According to a University of Illinois agricultural economist, when it comes to meeting the needs of the world’s growing population, that’s a lot of food falling through the cracks. Interestingly, farm managers who are aware of the factors that contribute to postharvest grain loss actually lose less grain. This was one of the findings in a study that examined how managers of large farms in the Brazilian state of Mato Grosso might be negatively affecting the efficiency of their own operations.

“Clearly there are things that you can do to reduce loss — you can put bed liners in trucks, you can adjust your combine, you can harvest more slowly — but for the farmers in Mato Grosso, it’s not a high priority,” says Peter Goldsmith. “It doesn’t seem rational. If you see soybeans bouncing off your windshield from the truck ahead of you and bands of soybeans along the berm, why wouldn’t you try to prevent it? It appears that farm managers in Brazil actually allow loss to happen because the cost of reducing loss is greater than the benefits.”

Goldsmith says one of the basic research questions of the ADM Institute for the Prevention of Postharvest Loss, which funded the study, is about why loss occurs. He says although there are hundreds of articles about postharvest loss, no one is working with the farm managers to find out, from a managerial and organizational perspective, what drives this loss. There is a discrepancy between the reality of the postharvest loss and what the managers believe to be acceptable loss.

Goldsmith explains that in tropical systems where the farming season lasts much longer than in the U.S., the more intensive production results in two crops a year on the same plot of ground — soybeans followed by corn.

“Because they are in such a hurry to get the soybean crop harvested so they can get the maize crop planted before the rainy season, they may harvest too fast, desiccate green soybean to advance harvest, or expose soybean to the weather during transport, all of which results in a 10 percent loss,” Goldsmith says. “The loss isn’t intentional but rather a level that the farm manager is willing to live with in order to get that second crop of corn.”

A lack of understanding and awareness is also part of the problem.

“When a farmer doesn’t think that harvest speed is important, they have more loss,” he says. “Likewise, if a farmer doesn’t think that combine adjustments are important, they’ll have more loss. Those who realize that maintaining equipment is important have less loss. Consequently, technical training in the field with the equipment could be beneficial. But the cost of reducing loss further, using current technology, may exceed the benefits. Farmers may be unwilling to pay or invest in loss reduction.”

In addition to harvest speed, the study identified several other factors contributing to grain loss: lack of truck regular maintenance; lack of adjustment to the combine at the platform; bad weather; bad road conditions; and a lack of employee training.

“What’s interesting is that the results from the survey were so mixed,” Goldsmith says. “Why wouldn’t farmers have agreed 100 percent that harvest speed contributes to loss? Insects and rodents seemed to be unimportant. Truck conditions and bad weather were the top factors to blame for loss, but truck conditions were mentioned by only 62 percent. These causes should be common knowledge, so I don’t know why 100 percent of the responses didn’t agree that, for example, poor road and truck conditions contribute to loss. The lack of definitiveness about this may indicate that loss is not a ‘front-of-mind’ issue for managers, which, in turn, has significant implications for policy makers seeking to reduce post-harvest loss.”

Goldsmith says these tropical farmers have a variety of issues at hand that trump loss.

“We may think of Brazil as sunshine and beautiful all the time, but farming is really tough in the tropics. There are pest pressures 24/7, soils are poor, there’s an extreme rainy season, distance to markets is great, and road conditions are very rough. All sorts of factors make farming tough, but this area of the world has the greatest potential to materially augment global grain supplies.”

For the study, an initial focus group of seven farmers was assembled to help frame the questions for an online survey. The survey respondents represent some of the largest farmers, not just in Mato Grosso, but in the world.

“This dominant class of medium and large tropical farm acreage operators who are producing most of the new grains are filling the gap between where we are now and where we need to be in 2050 to feed the world,” Goldsmith says. “Sure, we can expand our crop among the developed countries of the world, but we’re only helping at the margin. The potential for new grain producers on new land is coming from farmers in the Southern Hemisphere.”

The study is titled “Managerial factors affecting post-harvest loss: the case of Mato Grosso Brazil.”

Editor’s note: Levey Larson is a news and public affairs specialist for the University of Illinois in Urbana.