128 SEEDING AND PLANTING 



Haack's 1 investigations show that germinative energy instead 

 of germinative capacity is the important factor in seed quality. 

 He concludes that it is only the rapidly germinating kernels that fur- 

 nish the plants in open sowings. He states that with Scotch pine 

 7 days should be sufficient to settle the judgment on seed quality 

 rather than the longer period required for complete germination. 



The germinative energy period terminates with the rapid and constant 

 falling off in daily germination. Bates 2 has adopted the following 

 for marking the termination of this period. In a sample of 500 

 seeds the germinative energy period ends when the germination 

 drops below two seedlings in one day, if on the following day the 

 germination does not exceed two. When good fresh seed from the 

 same general locality and of the same species is tested under uni- 

 form conditions the period of vigorous germination for all samples is 

 remarkably uniform, so much so that a definite period can be fixed. 

 The length of this period varies not only with the species but with 

 the origin of the seed, the locality where it is to be used, and the 

 method of testing. Wiebecke 3 found from several thousand tests 

 on Scotch pine seed at the Eberswalde seed extracting establish- 

 ment that the time limit should be 7 days for that species. He 

 assumed that all seeds germinating during this period would be 

 valuable in nursery and field seeding, while those that germinated 

 later would be of little or no value. Bates states that the time is 

 modified by a change from loam to sand in the testing bed. Tests 

 under comparatively high temperatures on bibulous paper or 

 plates of porous clay in the germinating oven give a shorter 

 period than when the tests are made in soil in the hothouse. The 

 germinative energy period in days has been determined for many 

 species from the results obtained from tests. As the period is 

 fixed according to the judgment of the one making the tests and 

 the time varies with the origin of the seed and the method of 

 testing, there is more or less lack of uniformity in the results. 



When the seed is to be used in a region having a very short season 

 favorable to germination, the germinative energy period allowed in 

 the test should be correspondingly short. Bates places the germina- 



1 Haack, Oberforster: Der Kiefernsamen. (Zeitschrift f. Forst- u. 

 Jagdwesen, S. 353-381. 1909.) 



2 Bates, C. G.: The technique of seed testing. (Proc. Soc. Am. For., vol. 

 VIII, p. 134. 1913.) 



3 Wiebecke, Forstmeister: Die Anwendung neuen Erkennens und Konnens 

 auf die Kiefernsamendarre. (Zeitschrift f . Forst- u. Jagdwesen, S. 355. 1910.) 



