2. SEED SAMPLING
RL. AGRA w.4.L
Seed sampling is aimed at obtaining a sample of the required size and consisting of the same components as the whole lot of seeds. The quantity of seed tested in the laboratory is small, compared with the size of the seed lot which it is intended to represent. No matter how accurately the laboratory work is done, the results can only show the quality of the sample submitted for analysis. Consequently. every effort must be made to ensure that the sample sent to the seed testing laboratory accurately represents the seed lot in question. Seed Testing Laboratory personnels are not necessarily engaged in the sampling of seeds. But, nevertheless they should be well acquainted with the principles of seed sampling and should also be able to guide properly the p;rsons engaged in this job. INSTRUMENTS AND SUPPLIES REQUIRED FOR SAMPLING
1. Stick of sleeve-type trier (Bag trier)
Stick of sleeve-type trier consists of a hollow brass tube inside a closely fitting outer shell or sleeve which has a solid pointed end. The tube and sleeve have open slots in their walls so that when the tube is turned until the slots in the tube and sleeve are in line, seeds can flow into the cavity of the tube, and when the tube is given a half turn the openings are closed. "Thetubes vary in length and diameter and are made with or without partitions for different kinds of seeds (For clovers and other small free-flowing seeds packed in bags 762 mm trier with outside diamete of 12.7 mm and nine slots; and for cereals, 762 mm trier with outside diameter of 25.4 mm and six slots have been foundmoresuitable).lbis trieris used for drawing seed samples from the seed lots packed in bags or containers. 2. Bin sampler
Bin samplers are constructed on the same principle as bag triers but are much larger. ranging up to 1600 mm in length and 38 mm in diameter with six or nine slots. These samplers are used for drawing samples from the lots stored in the bins.
3. Nobbo trier
This trier is made in different dimensions to suit various kinds of seeds. It is a pointed tube, long enough to reach the centre of the bag, with an oval hole near the pointed end. The total length of the instrument should be aproximately 500 mm including a handle of about 100 mm and a point of about 60 mm leaving about 310 mm to penetrate into the bage, which should be sufficient to reach the centre of all types of bags. For cereals the intemal diameter of the tube should be about 14 mm but for clovers and similar seeds 10 mm is sufficient.
The Nobbo trier is suitable for sampling seed in bags but not in bulle 4. Miscellaneous supplies
This includes sample pans, bucket, stapler, sewing needles and thread, a piece of canvas (1 m x 1 m), sealing device, sam pIe bags, replacement labels and sealing tape (duly authenticated), hand lens, scissors, flash light and packing materials, stationery and stamps etc. .
A kit containing large and small sampling triers and misccllimoous supplies described above is a must for seed samplers to perform their job satisfactorily. GENERALPIDNCWLES
1. Sampling should be carried out only by persons trained and experienced in seed sampling and employed by the official organisations.
2. The seed lot shall be so arranged that each individual container or part of the lot is conveniently accessible. Upon request by the sampler, the owner shall provide full information regarding the bulking and mixing of the lot. When there is definite evidence of heterogeneity sampling should be reduced. In case of doubt, heterogeneity can be tested (Refer Appendix Chapter 9 ).
3. The size of the seed lot should also not exceed maximum seed lot size limits prescribed in Table 2.1 subject to a tolerance of 5%.
4. When sampling is being done by hand, great care should be taken to keep the fingers tightly closed around the seeds so that none may e.scape.Seed sampler may request that bags be emptied or partially emptied to...
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