•352 Missouri Agricultural Report. 



IMPURITIES OF FARM SEEDS. J 



CLASSIFICATION. 



The impurities carried by farm seeds have an important bearing on 

 -the real quality of the seed. Their quantity may be sufficient to unduly 

 increase the cost of the good seed and theii* character may be that of in- 

 jurious weeds. 



Seed impurities are classified (1) as inert material and (2) as for- 

 •eign seed, including both other crop seed and weed seeds. 



INERT MATERIAL. 



The inert material constitutes essentially such impurities as will not 

 vgrow (exclusive of dead seed), as chaff, empty seed hulls, broken seed, 

 pieces of stems and leaves, sand, dust, etc. The chief objection to such 

 material is that it replaces good seed, thus increasing the cost. In grass 

 ■seed the inert chaff misleads by causing the seed to present a better ap- 

 pearance than its quality justifies, as in bluegrass seed and chaff redtop 

 ■ seed. As compared with weed seeds, inert material is of minor import- 

 .ance, a fact not to be overlooked in the purchase and use of seed. The 

 practical seed test should point out clearly the relative importance of the 

 inert matter and of the weed seeds found in the sample. 



OTHER CROP SEEDS. 



Seed of various farm crops sometimes constitutes a part of the for- 

 'Cign seed. Its proportion as compared with the weed seed should be 

 noted in making the purity test. The importance to be attached to the 

 •occurrence of such crop seed depends on its nature ; for illustration, the 

 presence of timothy seed is detrimental to alsike clover seed used with a 

 wiew to alsike seed production, while for hay production a mixture of 

 'timothy and alsike seed often is preferable. 



WEED-SEED IMPURITIES. 



Quantity and Kinds of Weed Seeds. 

 Very few samples of forage-crop seeds are found wholly free from 

 -weed seeds. The methods of culture and of harvesting in vogue operate 

 -against a pure seed crop. The proportion of the weed seeds appearing 

 incidentally in the marketed seed is dependent on the number and char- 

 -acter of the weeds in the seed-producing crop and the extent to which the 

 ■«eed has been cleaned before being marketed. 



