Significant amounts of food are lost every year to postharvest waste, and the problem takes on global implications when studies show that this lost food could meet the minimum annual food requirements of millions of people. To address the problem, the Archer Daniels Midland Institute for the Prevention of Postharvest Loss is funding research collaboration between the University of Illinois and three universities in Brazil to measure and document postharvest losses of soybeans and corn.
The project components include identifying the extent and cost of harvest losses for farmers in the major soybean- and corn-growing states; studying losses to develop guidelines for proper handling, transportation, and storage of soybeans and corn; and analyzing costs of implementing structures for on-farm storage such as silo bags.
Grace Danao, an assistant professor in the Department of Agricultural and Biological Engineering at the U of I, is administering the grant from ADM. Richard Gates and Kent Rausch, professors in ABE, and Marvin Paulsen, professor emeritus in ABE, are also investigators with the project.
The Brazilian partners include the Universidade Federal de Viçosa, the Universidade Federal de Goias, and the Universidade Federal de Mato Grosso-Sinop. This group is committing resources towards the activities in the form of faculty time, graduate and undergraduate support, and materials and supplies.
Marvin Paulsen is leading the harvest loss measurement team, with collaboration from Francisco Pinto (UFV), Darly G. de Sena, Jr. (UFG), and Rodrigo S. Zandonadi (UFMT-Sinop). The team visited eight farms in Brazil in February to measure losses of soybeans during harvest season, and 11 farms in June to measure losses of corn during harvest season.
"It's important to measure loss at each step during harvest in order to understand total loss contributions," said Paulsen. "We measured pre-harvest, combine header, and threshing and separating losses using a standard method developed by EMBRAPA." (EMBRAPA is a state-owned company affiliated with the Brazilian Ministry of Agriculture.) The team also estimated yield in both crops. In soybeans, losses as a percent of yield went from a low of 1.4 percent to a high of 5.7 percent, or 0.88 to 4.45 sacks per hectare. In corn, losses as a percent of yield went from a low of 0.33 percent to a high of 3.64 percent, or 0.6 to 5.3 sacks per hectare.
"U.S. guidelines say if total crop losses are less than 3 percent, you're doing pretty well, but over that usually means you need to take time to stop and make adjustments to reduce them," said Paulsen. In both corn and soybeans, Paulsen said those adjustments could be as simple as slowing the speed of the combine and lowering the header. In both harvests, the combines with the highest losses were also running with the header high and at an advanced speed.
Paulsen said a large combine can easily harvest 4.5 hectares of soybeans an hour. "If the operators slowed down and saved two sacks per hectare, reducing those losses would theoretically save nine sacks an hour. At $28.60 per sack, that would be about $257 an hour. That's a tremendous savings to the enterprise."
"There has been much speculation about the amount of grain lost during harvesting in Brazil," said Francisco Pinto, a member of the research team from Universidade Federal de Viçosa. "The numbers found in this first year of measurements shows some farmers are doing a very good job adjusting their combines. Others still have room to improve their harvesting process. However," he continued, "the key point is to understand that without the research to determine these measurements, it would be impossible to make effective and efficient decisions."
Grace Danao and Rich Gates are the lead investigators studying transportation and storage losses. "Traditionally, soybean and corn production was in southern Brazil, and everything was exported from ports in the south," said Danao. "In the last 20 years, production has moved north, and transportation has become an issue."
Only 10 percent of the country's road network is paved, and more than 60 percent of agricultural production is transported by truck. "Losses during these long hauls have not been well documented," said Danao, "and it will be interesting to see if we can correlate particular segments of these roads [and their conditions] to losses, or if losses occur because the trucks are filled over their capacity."
Danao said they are working on using an instrumentation system that monitors temperature, moisture, air flow and carbon dioxide buildup in grain in trucks during transportation. "We want to measure not only quantity losses, but quality losses as well. We want to measure the nutritive quality of grain used for animal feed and how those properties change over time."
Danao said they are also studying the most common storage system used in Brazil, commercial elevators called graneleiros. Graneleiros are flat storages about 100 meters long and 50 meters wide, with a large V-shaped bottom made of concrete. Aeration is difficult to engineer and operate efficiently. The proper sizing of fans and ducts, and placement of ducts, must be practiced to maintain consistent air flow throughout the bed of grains.
"As production has increased, they have had to scale up their storage facilities," Danao continued. "We would like to assess the basic graneleiro and design, evaluate how current practices in filling and managing deep silos and graneleiros contribute to kernel damage, and compare air-flow measurements to designed air flow and assess adequacy and efficiency of aeration operations."
The third component of the study is designing, testing, and analyzing the costs of alternate structures for on-farm storage, said Danao. "Only 17 percent of the small farms have adequate grain storage. In Argentina and Paraguay, silo bags have been found to be a great temporary on-farm storage option. In Brazil, many farmers leave their corn in the field to dry, but they still don't have a way to store it. Silo bags may offer a temporary storage solution that allows the farmers to hedge and sell their corn at a higher price."
Danao said they also hope to partner with a facility such as a beef cattle operation. "They need to store a lot of grain for their feed mill," she said. "A side-by-side study of storing corn in a silo bag or in a structure allows us to compare to see if the quantity and quality of the nutrients and grain is different."
The entire project is ongoing, and Danao said the team hopes to be able to demonstrate low-cost and efficient strategies that can be adopted by small and large producers in the next three to five years.