Moisture content is reported on official grade certificates, but does not determine which numerical grade will be assigned to the sample. Moisture content affects the amount of dry matter being sold and purchased. Moisture is also an indicator for potential drying, has potential implications for storability, and affects test weight. Higher moisture content at harvest increases kernel damage during harvesting and drying, and the amount of drying required will affect stress cracks, breakage, and germination. Extremely wet grain may be a precursor to high mold damage later in storage or transport. While the weather during the growing season affects yield and the development of the grain, grain harvest moisture is influenced largely by the timing of harvest and harvest weather conditions.
- The U.S. Aggregate elevator recorded moisture in 2013 samples averaged 17.3%, significantly higher than 2012 (15.3%) and 2011 (15.6%).
- The range in moisture content was greater and standard deviation was higher in 2013 (2.24%) than in 2012 (1.72%) and 2011 (1.56%) indicating greater variability in harvest moisture.
- The U.S. Aggregate moisture values were distributed with 24.5% of the samples containing 15% or less moisture. This is the base used by most elevators for discounts and is a level considered storable for short periods during low winter-time temperatures.
- Only 10.0% of the 2013 crop contained 14% or less moisture compared to 31.7% in 2012 and 21.1% in 2011. Moisture of 14% is generally considered a safe level for longer storage and transport without drying.
- The distribution of moisture levels in the 2013 crop indicates a requirement for more drying than in the previous two years, with 75.4% of the samples above the base moisture of 15%.
- The U.S. moisture averages for corn from the Gulf, Pacific Northwest, and Southern Rail ECAs were 17.7%, 16.4%, and 16.6%, respectively. The Gulf ECA average moisture content has been consistently higher than in the other ECAs in all three years.
SUMMARY: GRADE FACTORS AND MOISTURE
- Although average test weight in 2013 (57.9 lb/bu or 74.5 kg/hl) was lower than in 2012 and 2011, it was nearly 2 lb/bu above the limit for No. 1 grade (56 lb/bu), indicating overall good quality.
- As the corn is commingled moving through the marketing channel, the average test weight in each ECA is not likely to fall below the minimum for U.S. No. 1 or No. 2 grade.
- BCFM of incoming corn was low with a 2013 U.S. Aggregate average of 0.9%, consisting primarily of broken corn. BCFM levels in almost all (97. 8%) of the corn samples were at or below the maximum of 3% allowed for U.S. No. 2 corn.
- The low average broken corn values in all three ECAs should minimize the need for cleaning and facilitate air flow during storage.
- The average foreign material values are low, indicating clean grain. The high levels of foreign material found in a few of the individual samples can be readily cleaned or commingled to minimize any significant handling problems in storage or marketing.
- Average total damage for 2013 was extremely low for incoming corn, with 95.7% having 3% or less damaged kernels, indicating that the corn should have good quality and store well. In addition, no heat damage was reported on any of the samples.
- Of the inbound elevator samples, 92.0% would grade U.S. No. 2 or better on all grade determining factors. Most elevators use U.S. No. 2 criteria as the base for pricing and discounts in domestic transactions . Over time, subsequent handling, drying, and storage may cause quality to be lower.
- The 2013 crop samples contained more moisture and more variability in moisture content, potentially requiring more drying at the point of first delivery than in the previous two years. The drying may result in additional stress cracking and breakage as the corn moves to export. This high average moisture combined with the larger range in moisture also indicates the need for segregation by moisture content and careful attention to drying and storing practices.