Speaker 1: Though many variables play a part in crop establishment, perhaps the most important is simply starting off right with high-quality seed, but what determines the quality of seed and how exactly do you test a sample?
A good quality seed will have a high germination percentage. Germination refers to the number of seeds planted that are expected to start sprout and grow. High germination usually results in good [stand 00:00:42] establishment.
Germination isn’t the only factor to keep in mind. Purity of the lot has significant impact on crop establishment. Purity refers to the kinds of seeds and other matter present in a bag of seed. Ideally, you would want to plant seed from a source with high pure seed percentage. Simply put, this means the lot has little inert matter and few weed and other crops seed. All of which could reduce [stand 00:01:13] and yield.
Whether you plan to plant the seed yourself or to package and sell it, it’s important to verify the quality of a lot of seed. This is where sampling and testing play very important roles.
Let’s consider three questions. How is the lot packaged? How much do you sample? How is the sample taken? Packaging differs according to seed kind, as well as geographic location. Some seed kinds, clover or tall fescue, for instance, are commonly sold in 20, 40, and 50 pound bags. In Western Kentucky, soybeans and wheat are often available in 1,000 to 3,000 pound mini bulk bags or in bulk bins. Finally, there are vegetable or flower seeds, which are typically packaged in small packs. These are treated differently because one or more full packets must be submitted to provide the minimum number of seeds needed for testing.
In a traditional bagged product, we need to determine how much product to sample. The lab analysis will be based on the sample you submit, so you want to make certain your sample represents the lot. Each trier that is obtained from a bag or a bin is actually a subsample of the lot.
Subsamples are combined in a single container at sampling, resulting in the composite sample. This composite sample is mixed and split down to a working amount for analysis by the seed laboratory.
Through extensive research, a standard formula was developed to ascertain how much seed was a good representative sample. The general rule is five bags plus 10 percent of the lot. Here’s how that works: for lots of six bags or less, each bag should be sampled and at least five trierfuls must be taken. For lots of more than six bags, five bag should be sampled plus 10% of the number of bags in the lot. Five is a minimum number of triers required. For example, this is a carryover lot of red clover with three bags left. The amount of seed obtained from each bag should be equal, to not bias the sample. In order to obtain the minimum of five triers and obtain an equal amount from each bag, you would sample each bag twice. When sampling the same bag more than once, be sure to follow a different path through the bag.
Let’s consider a larger lot, one that contain 36 bags. With this lot, the sample will consist of five bags plus 10 percent of the lot, total of 36, which is for more bags. All nine probes are randomly selected from the lot and are combined for the submitted sample. It is not necessary to sample more than 30 bags, so the minimum sample for any lot requires five probes and the maximum is 30 probes. Each sample should be taken randomly and evenly spaced throughout the lot.
Samples should always come from unopened bags. Check each bag before probing to make sure it is the same kind and lot to prevent mixing. By following the simpling guidelines, you will usually acquire enough seed for testing. For example, with small seeded crops, such as bentgrass, bluegrass, Alsike Clover, or Timothy, about two ounces is enough seed. For other small seeded crops like alfalfa, red clover, fescue, or lespedezas about 5 ounces is enough. A pound and a half is sufficient for crop like buckwheat or sorghum. Two and a half pounds are enough for seeds the size of barley, soybeans, or corn.
If you’re only testing for germination, a minimum of 800 seeds is required. If additional tests will be run, such as roundup tolerance or moisture, extra seed is necessary. Please note that with pelleted or coated seed, you may need to send additional seed as the coating material adds weight to the sample.
If you have questions, the seed lab will tell you how much seed to submit.
The type of seed not only determines the amount needed for testing, but also the method and equipment used to get the sample. Some seeds are more flowable than others, meaning they have a smooth seed coat and will flow into a trier very easily. Examples of flowable seed are clover, wheat, and crownvetch. Less flowable seeds are grasses, which are features on the seed that cause them to mat together. The least full will seed kinds are native grasses, which are extremely chaffy.
For sampling clovers and other small free-flowing seeds, a 30 inch trier with a half inch in diameter or double tube sleeve type trier should be used. For the rougher cereal grains, use a trier that is at least 30 inches long and seven eighths of an inch in diameter or a double tube sleeve trier. For other extremely choppy, nonfree flowing seeds, the lot can be sampled by hands.
The trier should be inserted in the corner of the bag and pushed diagonally across the bag. Triers must be inserted horizontally, though there are specially designed triers that don’t require that method. Take care not to rip or tear the container when sampling and be careful not to burst tire through the bag on the opposite side.
Caution should be exercised prevent damage to the seed. This is especially important when using a double sleeved trier, which can crisis even being closed. All trier fulls should be approximately the same size and remember to take a different path through the bag of its mysterious take more than one trier from each bag sampled.
When regulatory samples are taken, these same sampling procedures are followed: when an inspector samples a lot of bagged seed, the lot size is assessed and the seed kind, variety, and the lot number on the tag are verified. For example, this is 160 bag lot of tall fescue. Determine the number of bags to be sampled and what equipment is appropriate for the seed kind. Randomly determine which bags you will sample. Based on the sampling guideline of five plus ten percent, 21 bags should be sampled. Tall fescue is chaffy, so an AOAC trier will be the best tool for probing the bags.
Considerations for bulk sampling are a bit different. Draw samples from random positions. If a sleeve trier is used vertically, it must be partitioned.
In review, remember an Indiana trier is used for small seeds. An AOAC trier is used for chaffy seeds or larger seeds. A grain probe is used for large quantities of large seed. Special circumstances, as in sampling extreme chaffy seeds, like native grasses, may call for hand sampling.Sampling guidelines are available for members of AASCO, the Association of American Seed Control Officials.
Finally, always remember safety when sampling seed. Be aware of your surroundings, especially any potential hazards, including equipment operators, low clearance areas, and exposure to treated seat. Take necessary precautions, which may include wearing a bump hat, steel toed shoes, and latex gloves.
On the sample bag, please include the seed kind and variety, lot number, and if the seed is treated. Seal the samples into a sturdy bag or box and send to the testing facility. When having seed tested, be certain the lab is an AOSA approved lab. This ensures a lab meet certain qualifications in knowledge and proficiency.
At the lab, sample information, including the seed kind and a variety, lot number, treatments, as well as other data provided at submission, is logged into a database. Samples are divided into groups; those that require purity evaluations and those that require germination only.
Samples that require a complete analysis go to the purity lab prior to the germination lab. Germination only samples go directly to the germ lab. Samples are mixed prior to evaluation to eliminate any settling or segregation that may have occur to an transit. This is especially important with mixes that may have different size and weight seed. Samples that have a purity evaluation identified, mixed, and divided into a working weight. This ensures that the seeds being examined are typically of the submitted sample, which, if it has been sample properly, is typical of the lot.
Working weights are specific to seed kinds. The guidelines are published by the Association of Official Seed Analysts in the AOSA rules for testing seeds.
The working weight has two parts; the purity portion and the noxious weed portion. The purity portion is physically separated into pure seed, inert matter, and weed seed, and other crop seed. Any noxious weeds in this portion are also identified and counted. The noxious weed portion, which is typically 10 times that of the purity portion, is examined for noxious weeds only. Noxious weeds in Kentucky include …
All seed kinds found in the purity portion identified then weighed to determine the number per pound for the seed lot was sampled. The pure seed portion is packaged and sent the germination lab for germination testing.
Over in the germination laboratory, seeds are planted and placed and germination chambers according to strict rules. These rules deal with the number of seeds planted, temperature, light requirements, and any other special instructions.
At various times, samples are evaluated for sprouting and normal seedling development. At the final count, the total germination is recorded and a germination percentage is determined for that seed lot. The purity and germination information is reported to the submitter. These reports are important as they can be used to verify quality of the newly received seed lot, verify quality of carryover or stored seed, and used to generate a new or replacement seed label. W
We hope you’ve enjoyed our program. In the seed industry, the importance of a representative sample and the value of testing cannot be overstated, neither can the use of proper techniques and equipment. Consumers rely on accurate seed sampling and testing techniques to provide a basis for purchase and management decisions in regard to see quality. High-quality seed contributes to a well-established crop and brings farmers one step closer to a bountiful harvest. Farmers rely on knowledgeable seeds-man. The division of regulatory services assists the seed industry by monitoring , sampling, and testing products available in the marketplace to ensure accurate seed lot labeling.