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Like any other type of testing, the results received from seed analysis are only as good as the seed sample submitted. The sample should accurately represent the quality of the seeds in a seed lot.
A seed lot can be defined as a quantity of seed with every portion or every bag having been harvested, conditioned, and stored under uniform conditions. If there are variations, the quantity in question should be separated into two or more uniform lots.
For large size seeds like, soybeans or corn, about a quart of sample is needed. For medium size seeds, like sorghum or wheat, a pint to a quart of sample is needed. For small seeds, like clover or alfalfa, about one-half pint of sample is needed.
Bulk seed lots should be sampled with a grain probe or grain trier. Samples can be taken by hand, but it is more difficult to obtain a uniform sample.
Collect samples from eight to 12 locations throughout the bin or storage area. Avoid collecting samples from the very surface or very sides of the grain mass. These seeds have been exposed to more heating and cooling than seeds in the center and germination results may be lower.
Large round bins will require more samples than small round bins. If possible three samples should be pulled from the center of the bin, one about 2 to 3 feet from the top of the grain mass, the second from the vertical center of the grain mass, and the third about 2 to 3 feet above the floor.
In addition to the samples taken from the center, additional samples should be taken from a circle about a third of the way out from the center and about 3 to 5 feet deep.
For bins under 24 feet in diameter, take five probes equally spaced around the circle. For bins over 24 feet, increase the number of probes from six to 10 depending on the size of the bin. Samples from both 3-foot and 10-foot depths are suggested in large bins.
Samples can be taken periodically from the discharge spout of a running auger. Use care when interpreting these results because further movement of the grain through augers can result in additional mechanical damage to the seed.
Separate batches or lot numbers of seed should be sampled and analyzed separately. Sample individual bags of seed from corner-to-corner using a grain probe or grain trier.
¶ Table 1. |
||||||||
| Number of Bags | ||||||||
| in lot ………….. | 5 | 7 | 10 | 25 | 50 | 100 | 200 | 500 |
| to sample …. | 5 | 6 | 6 | 7 | 10 | 15 | 25 | 30 |
If a seed lot consists of six bags or less, take a sample from each bag. When lots are larger than six bags, take samples from five bags plus 10 percent of the remaining bags. Sample a minimum of six bags and a maximum of 30 bags.
Following are suggested numbers of bags to sample for different sized seed lots:
Seed samples must be mixed thoroughly. Do not sort out any inert material from the sample. Inert material includes stems, rocks, trash, etc.
If the sample is too large, one way to reduce sample size is by quartering. Mix the entire sample, then pour it into a pile on clean paper or plastic. Then divide the sample into four equal parts (quarters) saving the opposite two quarters. If the sample is still too large, repeat the procedure until obtaining the proper sample size.
Always ship samples in a crush-proof or well-padded container. Seeds damaged during shipping will germinate poorly. Make sure the container is completely full to prevent seeds from bouncing around and getting damaged. Cloth bags or suitable plastic containers also work well. Do not ship in glass or breakable containers.
Saha, et. al. 2013. Common Terms Used in Animal Feeding and NutritionUniversity of Georgia Cooperative Extension Bulletin 1367. 20 pg.
McGuire, M.A. Nutrition and Feed Terms. Dairy Cattle Management cooperative course materials. Univsity of Idaho and Washington State University . 6 pg. http://www.webpages.uidaho.edu/avs472/Word/Nutrition/Nutrition%20and%20Feed%20Terms.pdf accessed 01Feb2017
French, P. 2004. Animal Science 312: Applied Animal Nutrition, Feedstuffs and Ration Formulation. Oregon State Univ. Extended Campus, Oregon State Univ., Corvallis OR accessed