the presence of foreign matter in seeds, determined by seed analysis and expressed as a percentage of weight or in items per kg of seed.
According to the Ail-Union State Standard 12037–66, foreign matter includes substandard seeds of the main crop—small, underdeveloped, sprouted (if the sprout is at least half the seed), rotted, crushed, cracked, or damaged by pests (if half of the seed or more is lost, regardless of whether the embryo is preserved); seeds of other cultivated plants; seeds of weeds; fungus formations (smut and so forth); wheat nematode galls; live pests and their larvae; and nonliving matter of organic or mineral origin (stem fragments, bits of earth, and so forth). Small and underdeveloped seeds (of wheat, rye, oats, small-seed leguminous grasses) are those seeds that pass through a standard-size sieve and very wrinkled seeds that are less than one-third the normal size (in flax, less than one-half). Many contaminants not only litter the field but also lower its yield and quality. Hence, analysis serves to determine both the degree of contamination and the composition of the contaminants. Seed material that exceeds the established standards for allowable impurity undergoes additional separation.
M. K. FIRSOVA