Agriculture Reference
In-Depth Information
Figure 4.4. Microscopic-aided inspection station utilizing a mechanical method of conveying a stream of
seed across the ield of view (courtesy of Oregon State University Seed Laboratory).
Figure 4.5. Analytical balance. After the separation of sample components, each part is weighed on a balance
and the percentage of each component (e.g., pure seed, inert matter) is determined.
places. To ensure accuracy, balances should be regularly calibrated by an external service and monitored
using check weights. The AOSA rules specify that a working sample be weighed in grams to four signiicant
igures and that the four component parts be weighed in grams to the same number of decimal places as the
working sample. Sample weights of less than one gram should be weighed to an accuracy giving four digits
beyond the decimal (e.g., 0.5012) as should each of the component parts. Where working samples weigh
more than one gram (e.g., 1.012), all digits are considered as signiicant whether they appear before or after
the decimal. Consequently, the weights of all component factors should be measured to three digits after the
decimal.
