Testing Farm Seeds. 369 



ture represents 85 i)er cent of the original sample. The trefoil adulterant 

 therefore amounts to -lO per cent of 85 per cent, or 34 per cent of the 

 seed under test. 



Examination of Weed Seed's. — The weed seeds should be examined 

 for kinds representing important weeds. A knowledge of what import- 

 ant weed seeds are liable to occur in particular kinds of crop seed is ver^^ 

 helpful. For this reason the results of many tests are utilized in the sub- 

 sequent remarks on testing particular kinds of seed. Suspected weed 

 seeds should be carefully compared with the illustrations relating to this 

 class of seeds. Many kinds of weed seeds not illustrated in this bulletin 

 will be found. Most of these, as a rule, are of relatively minor import- 

 ance. 



The Germination Test. — It is important in separating pure seed for 

 the germination test that the counting be done indiscriminately — without 

 selection as to the appearance of the seed. The tendency of the beginner 

 is to select the more promising-looking seeds for the germination test. 

 It must not be forgotten that the purpose of the test is to learn what 

 percentage of the total pure seed will germinate. If the more promising 

 seed is selected, the results of the test are deceiving in favor of the dealer. 

 Of small seeds (such as forage crop and cereals), 200 are counted; 

 of larger seeds 100 are taken, each in duplicate. In the special individual 

 ear tests of corn only a few seeds are used. In adulterated samples the 

 necessary number of pure seeds can usually be obtained from the separa- 

 tion of the 1,000 seeds. It is obvious that accurate counting is important 

 to insure accuracy in computing the result. 



The conditions essential to seed germination are sufficient moisture, 

 warmth and air. Sufficient water should be supplied to keep the seeds 

 thoroughly moistened during germination, but they should not be allowed 

 to rest in water. The temperature of living rooms ranging from 65° to 

 85° F. is suitable for germinatioii. A place in the room should be selected 

 where the day and the night temperatures will be fairly uniform. Thus 

 the window sill is too cold in winter and a shelf directly over the stove is 

 too warm. The germination of some kinds of seeds is favored by the 

 varying day and night temperature of living rooms. Germinating seeds 

 must be supplied with fresh air. If the air is confined, it loses its oxygen, 

 which is necessary to germination, and there is no means for escape of 

 carbon dioxide, a gas produced by the germination process, but detri- 

 mental to it. A proper covering of cloth, paper, wood, or glass for the 

 seed germinator which prevents too rapid loss of moisture by evaporation, 

 while not hindering the admission of air, should not be neglected. In 

 order to insure sufficient air, very small seeds germinate best on top of 



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