The broad plains of the American Midwest and the arid desert of Abu Dhabi have little in common, but together they form the research milieu of NYU Abu Dhabi Assistant Professor of Engineering Douglas Cook, who conducts forensic engineering analysis on corn stalks.
Cook is trying to determine what causes corn stalks to buckle and topple over. For his efforts, he recently won a major grant from the National Science Foundation in the United States to pursue this research.
Through field observations in American corn fields and structural analysis conducted in his lab at NYUAD, Cook has identified weaknesses that lead to stalk failure, which costs the agricultural industry huge amounts of money each year.
If researchers are able to produce crop varieties that are less susceptible to stalk failure, farmers will be able to bring more crop to market.
Also called maize, corn stalks look similar to bamboo shoots, to which they are related. Stalks are composed of cylindrical sections of several inches followed by "knuckles" that join the sections. Failures occur most often near the knuckles, Cook said.
Other researchers have studied stalk failure, but Cook and his team are taking a novel approach. Biologists have tended to look at the stalk problem from the minute scale of molecular biology, while plant breeders look at the same problem from the grander scale of the crop field. "What we're doing — to look at failure at the level of individual stalks — is between these two extremes," Cook said.
The rate of crop failure — estimated at between 10 and 20 percent — can be partially attributed to the work of breeders who have been successful at improving yield by increasing the size of the ear of corn. This approach has produced ears that are packed with harvestable kernels, but breeding for high yield saps strength from the stalk.
"We could make the stalk stronger by making it bigger," Cook said, "but that's a bad solution because whenever the stalk gets bigger the yield goes down. So we're trying to make the stalks stronger by making the smallest change possible." Finding a solution may be addressed by geometry: altering the structure of the stalks instead of making them thicker or heavier.
In the lab at NYUAD, Cook has developed a new test that has successfully replicated stalk failures as he has observed them in the field. With a "bending test," the stalk is supported at both ends while force is applied to the middle of it until it breaks. "It seems simplistic, but we have to perform the test in a particular way in the lab or we won't get the same failure patterns that we see in the field," Cook said.
The work funded with the NSF grant will progress in stages. The team has conducted bending test (or engineering failure) analysis. It will then carry out intricate analysis of the broken stalks using a CT scanner. This tool provides the researchers with information about the geometric structure of the stalks.
"Now that we know that the lab failure patterns match the field failure patterns we can start to make correlations between geometry and strength of the stalks," Cook said. "This helps us figure out which geometric features appear to be controlling strength." Breeders can then breed for these particular geometric characteristics.
Going forward, it's possible that the researchers will see improvements in strength in as soon as one season. It will, however, take years to bring a new breed to market, since the new crop will need to undergo rigorous testing and approval.