Fig. 1. A typical filling hopper and stand for the specific filling the quart or pint cups for serial test load determination. (Image: www.seedburo.com).
Fig. 2. Corn grain test weight versus grain yield because that 27 hybrids grown at 3 Kansas areas (Lingenfelser et al, 2011) . Click on image to view larger version.

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Fig. 3. Corn grain test load versus serial yield for 22 hybrids grown in ~ Greenville, oh in 2012 (drought) and 2013 (ample rainfall). Click image to view larger version.
update September 2021 URL: http://www.kingcorn.org/news/timeless/TestWeight.html grain Test weight Considerations because that Corn R.L. (Bob) Nielsen Agronomy Dept., betterworld2016.org Univ. West Lafayette, IN 47907-2054 email address: rnielsen at betterworld2016.org.edu Twitter:

The main minimum allowable test load in the U.S. Because that No. 1 yellow corn is 56 lbs/bu and for No. 2 yellow corn is 54 lbs/bu (USDA-AMS (FGIS), 1996). Corn grain in the U.S. Is marketed on the communication of a 56-lb "bushel" nevertheless of test weight. Also though grain moisture is not part of the U.S. Criter for corn, grain buyers salary on the communication of "dry" bushels (15 come 15.5% grain moisture content) or discount the sector price come account for the drying prices they intend to incur handling wetter corn grain.

Growers worry about low test weight because local grain buyers often discount their industry bids for short test load grain. In addition, growers are normally disappointed when they deliver a 1000 bushel (volumetric bushels, the is) semi-load the grain that averages 52-lb test weight since they only get paid because that 929 56-lb "market" bushels (52,000 lbs ÷ 56 lbs/bu) to add they obtain a discounted price because that the low test load grain. Top top the other hand, high test load grain provides growers feel good when they provide a 1000 bushel semi-load of grain the averages 60 lb check weight because they will gain paid because that 1071 56-lb "market" bushels (60,000 lbs ÷ 56 lbs/bu).

These emotions encourage the belief that high test weight grain (lbs that dry matter per volumetric bushel) is associated with high grain yields (lbs. That dry matter per acre) and also vice versa. However, there is small evidence in the research literature that serial test weight is strongly related to grain yield.

Hybrid variability exists because that grain check weight, however does not instantly correspond to distinctions in genetic yield potential. Serial test weight for a given hybrid frequently varies from ar to field or year to year, but does not immediately correspond to the all at once yield level of one environment.

Similarly, grain native high yielding fields does no necessarily have higher test weight than that from lower yielding fields. In fact, test load of grain harvested from severely stressed areas is occasionally greater than the of grain from non-stressed fields, as shown in Fig. 2 for 27 corn hybrids grown in ~ 3 places with widely differing yield level in Kansas in 2011. Another example indigenous Ohio with 22 hybrids grown in usual in the drought year of 2012 and also the much far better yielding year the 2013 additionally indicated no relationship in between yield level and also grain test load (Fig. 3).

Conventional dogma argues that short test weight corn serial decreases the processing efficiency and also quality of handle end-use products like corn starch (U.S. Grains Council, 2020), back the research literature does not consistently support this id (Yang et al., 2000). Similarly, low test corn serial is often thought come be inferior for pet feed quality, although again the research literature does not support this id (Laborie, 2019; Rusche, 2020; Simpson, 2000; Wiechenthal Pas et al., 1998). Even if it is or not low test weight grain is inferior to greater test weight grain may depend ~ above the cause of the short test weight in the an initial place.

Common reasons of short Grain Test load

The 2009 corn harvest season in Indiana (late crop maturation, late harvest) was an instance of one whereby there were much more reports of low test weight corn serial than great or above average check weights. There were mostly six factors that accounted for many of the low test weight grain in 2009 and also four shared a usual overarching effect.

Grain Moisture

First and also foremost, growers should recognize that test weight and also grain moisture room inversely related. The higher the serial moisture, the lower the test load AT THAT point IN TIME. Together grain dries in the ar or in the dryer, test weight naturally rises as lengthy as kernel integrity continues to be intact. Test weight rises as grain dries partly because kernel volume often tends to shrink through drying and also so much more kernels pack right into a volume bushel and also partly due to the fact that drier serial is slicker which has tendency to encourage kernels to pack much more tightly in a volume bushel. Thus in a year favor 2009 with plenty of of the initial harvest reports of grain moisture varying from 25 come 30% rather of the usual starting moisture level of about 20 come 23%, it should not it is in surprising the test weights were lower than expected.

Hellevang (1995) offered a simple formula for estimating the rise in check weight with grain drying. In its most basic form, the equation is (A / B) x C; whereby A = 100 - dried moisture content, B = 100 - wet moisture content, and also C = test load at wet humidity content. The author does not say, yet I doubt this basic formula is many applicable within a "normal" range of harvest moistures; as much as moistures in the mid- to high 20"s.

Example: dry moisture = 15%, Wet humidity = 25%, Test load at 25% = 52 lbs/bu.

Estimated test load at 15% moisture = ((100 - 15) / (100 - 25)) x 52 = (85/75) x 52 = 58.9 lbs/bu

An older reference (Hall & Hill, 1974) supplies an alternate suggestion because that adjusting test load for harvest moisture that likewise accounts because that the level of kernel damage in the harvested grain (Table 1). The table worths are based upon the premise the kernel damage itself lowers test load to start with and that further drying of damaged grain results in less of boost in test weight the what occurs in undamaged grain. Contrasted to the outcomes from making use of Hellevang"s an easy formula, adjustments to check weight making use of these tabular values often tend to an outcome in smaller sized adjustments to test load for high humidity grain at harvest, but larger adjustments for drier grain in ~ harvest.


Stress throughout Grain Fill

Secondly, thirdly, and also fourthly; drought stress, late-season foliar leaf conditions (primarily gray sheet spot and also northern corn leaf blight), and below common temperatures throughout September of 2009 all brought about a significant deterioration of the crop"s photosynthetic machinery beginning in at an early stage to mid-September the "pulled the rug the end from beneath" the effective completion the the serial filling duration in part fields; resulting in less than optimum starch deposition in the kernels. Fifthly, beforehand October frost/freeze damage to late-developing, immature areas resulted in sheet or totality plant death that effectively put an end to the grain-filling procedure with the same an adverse effect on check weight.

Ear Rots

Finally, ear rots (diplodia, gibberella, etc.) were widespread throughout many locations of Indiana in 2009. Kernel damages by this fungal pathogens results in light-weight, chaffy grain that also results in low test weight diseased grain, damaged kernels, and also excessive levels of international material. This reason of low test load grain obviously outcomes in worse (if not toxic) pet feed top quality grain, unacceptable end-use processing consequences (ethanol yield, DDGS quality, starch yield and quality, etc.), and difficulties in save on computer the damaged grain without further deterioration.

Related reading

Bern, Carl and also Thomas Brumm. 2009. Grain Test weight Deception. Iowa State extension Publication PMR-1005. Https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1035&context=abe_eng_pubs. .

Bradley, Carl. 2009. Diplodia Ear Rot Causing troubles in Corn throughout the State. The Bulletin, Univ the Illinois Extension. Http://ipm.illinois.edu/bulletin/article.php?id=1233. .

Hall, Glenn and Lowell Hill. 1974. Test weight Adjustment based on Moisture Content and also Mechanical damages of Corn Kernels. Trans. ASAE 17:578-579.

Hellevang, Kenneth. 1995. Grain Moisture content Effects and Management. North Dakota State expansion Publication AE-905. Http://www.ag.ndsu.edu/extension-aben/documents/ae905.pdf. .

Hellevang, Kenneth. 2012. Grain productivity Not concerned Test Weight. Expansion & Ag research study News, north Dakota State Univ. Https://www.ag.ndsu.edu/news/newsreleases/2012/aug-20-2012/grain-yield-not-related-to-test-weight .

Hellevang, Kenneth. 2019. Plenty of Factors influence Corn check Weight. Phibìc Dakota State Univ. Extension. Https://www.ag.ndsu.edu/news/newsreleases/2019/nov-25-2019/many-factors-influence-corn-test-weight

Hicks, D.R. And H.A. Cloud. 1991. Calculating Grain weight Shrinkage in Corn because of Mechanical Drying. betterworld2016.org expansion Publication NCH-61 http://www.ces.betterworld2016.org.edu/extmedia/nch/nch-61.html .

Hill, Lowell D. 1990. Grain Grades and Standards: Historical issues Shaping the Future. Univ. That Illinois Press, Champaign, IL.

See more: Lắc Tay Vàng Dưới 1 Triệu - Nhẫn Nam Skymond Dành Cho Quý Ông Thanh Đạt

Hurburgh, Charles and also Roger Elmore. 2008. Corn Quality worries in 2008 - Moisture and Test Weight. Incorporated Crop administration News, Iowa State Univ. Extension. Https://crops.extension.iastate.edu/cropnews/2008/10/corn-quality-issues-2008-moisture-and-test-weight. .

Hurburgh, Charles and Roger Elmore. 2008. Corn Quality issues in 2008 – warehouse Management. Combined Crop administration News, Iowa State Univ. Extension. Https://crops.extension.iastate.edu/cropnews/2008/10/corn-quality-issues-2008-�-storage-management. .

Laborie, Erin. 2019. Feeding light Test weight Corn in Growing and Finishing Diets. Univ. The Nebraska Extension. Https://beef.unl.edu/beefwatch/feeding-light-test-weight-corn-growing-and-finishing-diets

Lingenfelser, woman (sr. Author). 2011. Kansas chop Performance Tests v Corn Hybrids (SRP1055). Kansas State University agricultural Experiment Station and also Cooperative extension Service, Kansas State Univ.

Nafziger, Emerson. 2003. Check Weight and Yield: A Connection? The Bulletin, Univ of Illinois Extension. Http://ipm.illinois.edu/bulletin/pastpest/articles/200323h.html. .

Rankin, Mike. 2009. Understanding Corn test Weight. Univ Wisconsin Extension. Https://fyi.uwex.edu/grain/files/2009/12/CornTW09.pdf.

Rusche, Warren. 2020. Feeding value of Light-Test weight Corn. IGrow, southern Dakota State Univ Extension. Https://extension.sdstate.edu/feeding-value-light-test-weight-corn

Simpson, Greg. 2000. An overview of research study on Feeding short Test load Corn come Pigs. Ontario to adjust of Ag, Food, and Rural Affairs. Http://www.omafra.gov.on.ca/english/livestock/swine/facts/info_n_summary.htm

USDA-AMS (FGIS). Sep 1996. Subpart D the U.S. Standards for Corn. U.S. Standards. U.S. Department of farming - farming Marketing business (Federal Grain inspection Service). Https://www.ams.usda.gov/sites/default/files/media/CornStandards.pdf. .

USDA-AMS (FGIS). Oct 2020. Grain inspection Handbook, book II: serial Grading Procedures. United says Department of agriculture - agricultural Marketing business (Federal Grain investigate Service). Https://www.ams.usda.gov/sites/default/files/media/Book2.pdf

USDA-AMS (FGIS). . Test weight per Bushel. in Corn Grading Tutorial. United says Department of agriculture - farming Marketing company (Federal Grain investigate Service). Https://apps.ams.usda.gov/elearning/Grading/Grading_Corn/presentation_html5.html. .

U.S. Seed Council. 2020. Check Weight. in Corn fiddle Cargo quality Report 2019/2020. U.S. Grains Council. Https://grains.org/corn_report/corn-harvest-quality-report-2019-2020/4/

Woloshuk, Charles and Kiersten Wise. 2009. Diplodia Ear Rot. betterworld2016.org extension Publication #BP-75-W. Https://www.extension.betterworld2016.org.edu/extmedia/BP/BP-75-W.pdf. .

Yang, P., R. J. Shunk, A. E. Haken, Y. X. Niu, S. H. Zou, P. Buriak, S. R. Eckhoff, M. E. Tumbleson. 2000. Yield, Protein Content, and Viscosity of strength from Wet-Milled Corn Hybrids as affected by Environmentally Induced transforms in test Weight. Cereal Chemistry 77 (1):44-47. Https://onlinelibrary.wiley.com/doi/epdf/10.1094/CCHEM.2000.77.1.44 .