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Corn Export Cargo Quality Report 2014/2015

Contents

  1. Export Cargo Quality Highlights
  2. Introduction
  3. Quality Test Results
  4. Moisture
  5. Chemical Composition
  6. Physical Factors
  7. Mycotoxins
  8. U.S. Corn Export System
  9. U.S. Corn Export Flow
  10. Impact of the Corn Market Channel on Quality
  11. U.S. Government Inspection and Grading
  12. Survey and Statistical Analysis Methods
  13. Survey Design and Sampling
  14. Statistical Analysis
  15. Testing Analysis Methods
  16. Corn Grading Factors
  17. Moisture
  18. Chemical Composition
  19. Physical Factors
  20. Mycotoxin Testing
  21. U.S. Corn Grades and Conversions
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III. QUALITY TEST RESULTS

A. Grade Factors

The USDA’s Federal Grain Inspection Service (FGIS) has established numerical grades, definitions and standards for grains. The attributes which determine the numerical grades for corn are test weight, broken corn and foreign material (BCFM), total damage and heat damage. The table for “U.S. Corn Grades and Grade Requirements” is provided on page 49 of this report.

SUMMARY: GRADE FACTORS AND MOISTURE

  • Average U.S. Aggregate test weight (57.5 lb/bu) was higher than 2013/2014 (57.3 lb/bu), lower than 3YA (57.7 lb/bu), and above the limit for U.S. No. 1 grade corn (56 lb/bu).
  • Average U.S. Aggregate BCFM (3.0%) was higher than in previous years. However, approximately 45% of the export samples contained levels at or below the maximum allowed for U.S. No. 2 grade (3%).
  • Average U.S. Aggregate total damage (2.3%) and heat damage (0.0%) were well below the limits for U.S. No. 1 grade.
  • Test weight, total damage, and heat damage averages for the corn loaded for U.S. No. 2 o/b or U.S. No. 3 o/b contracts were better than U.S. No. 1 grade.
  • BCFM averages were below the grade limits of the U.S. No. 2 o/b and U.S. No. 3 o/b contracts.
  • Average U.S. Aggregate moisture content (14.5%) was the same as 2013/2014 but higher than 3YA (14.3%).
  • Fewer 2014/2015 export samples had moistures above 14.5% than 2013/2014, indicating a higher proportion of export samples with satisfactory levels for safe transport to international markets than last year.

1. Test Weight

Test weight (weight per volume) is a measure of bulk density and is often used as a general indicator of overall quality and as a gauge of endosperm hardness to alkaline cookers and dry millers. It reflects kernel hardness and kernel maturity. Test weight is initially impacted by genetic differences in the structure of the kernel. However, it is also affected by moisture content, method of drying, physical damage to the kernel (broken kernels and scuffed surfaces), foreign material in the sample, kernel size, stress during the growing season, and microbiological damage. High test weight at the export point generally indicates high quality, high percent of horneous (or hard) endosperm, and sound, clean corn.

RESULTS

  • Average U.S. Aggregate test weight (57.5 lb/bu or 74.0 kg/hl) was higher than 2013/2014 (57.3 lb/bu), but lower than 2012/2013 (58.1 lb/bu) and 3YA (57.7 lb/bu). However, the average U.S. aggregate test weight was above the limit for U.S. No. 1 grade (56.0 lb/bu).
  • Variation in the 2014/2015 export samples was more than in previous years, as indicated by the higher standard deviation (0.90%) compared to 2013/2014 (0.87%) and 3YA (0.75%). The range in values was also greater than 2012/2013 but less than 2013/2014.
  • Nearly 85% of all samples’ test weights were at or above the minimum for U.S. No. 1 grade (56 lb/bu) and 98.0% were above the limit for U.S. No. 2 grade (54 lb/bu).
  • Test weight at export was nearly the same as at harvest (57.6 lb/bu or 74.2 kg/hl). Changes in test weight between harvest and export usually have been very small.
  • The 2014/2015 export samples’ variability (0.90%) was less than the 2014 harvest samples (1.34%). As corn is commingled moving through the market channel, test weight may change somewhat, but it becomes more uniform with lower standard deviation and smaller range between maximum and minimum values than at harvest.
  • Test weight was higher in samples from the Gulf (58.0 lb/bu) and Southern Rail (58.0 lb/bu) ECAs, with lower variability, compared to samples from the Pacific Northwest ECA (55.4 lb/bu).
  • Average test weight of corn for contracts loaded as U.S. No. 2 o/b (57.5 lb/bu) was slightly higher than for contracts loaded as U.S. No. 3 o/b (57.4 lb/bu). Averages for both of these contracts were above the limit for U.S. No. 1.

2. Broken Corn and Foreign Material (BCFM)

Broken corn and foreign material (BCFM) is an indicator of the amount of clean, sound corn available for feeding and processing. As corn moves from farm deliveries through the market channel, each impact on the grain during handling and transporting increases the amount of broken corn. As a result, the average BCFM in most shipments of corn will be higher at the export point than in deliveries to the local elevator.

Broken corn (BC) is defined as corn and any other material (such as weed seeds) small enough to pass through a 12/64th inch round-hole sieve, but too large to pass through a 6/64th inch roundhole sieve. Foreign material (FM) is defined as any non-corn pieces too large to pass through a 12/64th inch round-hole sieve, as well as all fine material small enough to pass through a 6/64th inch roundhole sieve.

The diagram to the right illustrates the measurement of broken corn and foreign material for the U.S. corn grades.

RESULTS

  • Average U.S. Aggregate BCFM in export samples (3.0%) was at the maximum for U.S. No. 2 grade. It was higher than 2013/2014 (2.9%), 2012/2013 (2.7%), and 3YA (2.9%).
  • The variability of the 2014/2015 export samples (with a standard deviation of 0.65%) was approximately the same as 2013/2014 (0.65%) but lower than 2012/2013 (0.68%) and 3YA (0.66%).
  • BCFM in export samples was distributed with 45.3% of the samples at or below the limit for U.S. No. 2 grade (3%) and 85.0% at or below the limit for U.S. No. 3 grade (4%).
  • Average BCFM at export (3.0%) was higher than at harvest (0.8%), as expected. This increase is consistent with previous years and is likely a result of increased breakage and stress cracks created by drying and handling impacts.
  • BCFM at export was lower in the Southern Rail ECA (1.8%) than in either the Gulf (3.1%) or Pacific Northwest (3.6%) ECAs.
  • Average BCFM for contracts loaded as U.S. No. 2 o/b was 2.7% compared to the average BCFM of 3.6% for contracts loaded as U.S. No. 3 o/b. Corn arriving at the export point is normally commingled from many origins to meet the limits for the contracted grade. Cleaning and loading procedures at the export point are designed to bring each factor close to but within the limits of each factor limit for grades U.S. No. 2 and U.S. No. 3. Thus, BCFM would be expected to be lower for No. 2 o/b than No. 3 o/b corn contracts, because the contracts specify 3.0% and 4.0% for U.S. No. 2 and U.S. No. 3, respectively.

3. Total Damage

Total damage is the percentage of kernels and pieces of kernels that are visually damaged in some way, including damage from heat, frost, insects, sprouting, disease, weather, ground, germ and mold. Most of these types of damage result in some sort of discoloration or change in kernel texture. Damage does not include broken pieces of grain that are otherwise normal in appearance. Mold damage and the associated potential for mycotoxins is the damage factor of greatest concern. Mold damage is usually associated with higher moisture content and high temperature during growing and/or storage conditions.

Corn with low levels of total damage is more likely to arrive at destination in good condition than corn with high levels of total damage. High levels of total damage have the potential of increasing moisture and microbiological activity during transport.

RESULTS

  • Average U.S. Aggregate total damage (2.3%) was higher than 2013/2014 (1.7%), 2012/2013 (2.0%), and 3YA (1.8%), but still below the 3.0% limit for U.S. No. 1 grade.
  • Variability in the 2014/2015 export samples was lower than 2013/2014 and 2012/2013 as indicated by the lower standard deviation (0.92% compared to 1.10% and 1.24%, respectively) and the similar or tighter range (7.0% compared to 7.0% and 9.1%, respectively).
  • Of the export samples, 69.6% had 3.0% or less damaged kernels, meeting the requirement for U.S. No. 1 grade. Nearly 98% of the samples were below the limit for U.S. No. 2 grade (5.0%).
  • The average level of total damage increased in the market channel, from 1.7% at local elevators to 2.3% at export. This increase leaves the corn well within the grade limits despite the original moisture content and the time in storage and transport. This indicates good management practices in the market channel.
  • The Pacific Northwest had lower total damage (0.4%) compared with the Gulf (2.8%) and the Southern Rail (2.7%) ECAs.
  • The Southern Rail ECA had a greater increase in total damage (1.3% to 2.7%) between harvest and export than the other ECAs. The Pacific Northwest ECA had the smallest change in total damage (0.0%), which has been the pattern in previous years. Lower moisture and cooler temperatures at harvest may be a partial explanation for the consistent pattern of the smaller increase in total damage in this ECA.
  • Total damage for contracts being loaded as U.S. No. 2 o/b and U.S. No. 3 o/b were both 2.3%.

4. Heat Damage

Heat damage is a subset of total damage in corn grades and has separate allowances in the U.S. Grade standards. Heat damage can be caused by microbiological activity in warm, moist grain or by high heat applied during drying. Low levels of heat damage may indicate the corn has been stored at appropriate moisture and temperatures prior to delivery to the export point.

RESULTS

  • Only two samples in the entire sample set showed any heat damage in export samples in 2014/2015. This number has also been well below the limit for U.S. No. 1 grade in previous years, indicating good management of drying and storage of the corn through the market channel.