Each year the American Soybean Association and the US Soybean Export Council supports a survey of the quality of the new US soybean crop. This survey is intended to provide new crop quality data (composition characteristics) to aid international customers with their purchasing decisions. This year’s report was just published and made available to customers of soybeans.
Each year researchers at the University of Minnesota request representative soybean samples from farmers based on total land devoted to soybean production in each state; this provides a response distribution that closely matches U.S. soybean production. The soybean samples are analyzed for protein, oil, and amino acid concentration by near-infrared spectroscopy (NIRS) using a Perten DA7250 diode array instrument with calibrations developed by the University of Minnesota and Perten.
Overall, the 2014 U.S. soybean crop quality, as measured by protein and oil concentration, decreased slightly from that of the excellent 2013 crop. Average U.S. soybean protein concentration was 0.4 percentage points lower in 2014, at 34.3%, and average US oil concentration was 0.3 percentage points lower at 18.7% when compared with 2013. As is noted in most years, Western Corn Belt states showed slightly lower protein concentrations than the US crop; the Western Corn Belt soybeans had oil levels very near the US average. Soybeans grown in the Eastern Corn Belt and the Midsouth had higher protein concentrations than the US average; however, the Eastern Corn Belt oil was slightly below the US average, but the Midsouth oil came in a full percentage point above the US average. The Southeast region had a lower protein concentration than the US average, whereas, the Southeast oil average was higher than nearly all of the other regions. East Coast states produced a soybean crop very near the US average for protein and oil concentrations.
The 2014 amino acid results were similar to those found in 2013, there was little regional variation for lysine (expressed as a percent of the 18 primary amino acids) or the five most limiting amino acids (cysteine, lysine, methionine, threonine, and tryptophan). Regional differences alone did not appear to explain amino acid concentration differences in the samples. Rather, the researchers found amino acid concentrations in the 30% of samples with the highest protein (390 samples) content had a significantly lower sum of the five most limiting amino acids, 14.5%, compared to the bottom 30% for protein that had a sum of the five limiting amino acids of 14.8%. The protein in lower protein samples is more concentrated in those five amino acids than is the protein in higher protein samples.
