Aug. 14, 1916 Agricultural Value of Impermeable Seeds 



771 



exclusively seeds grown in 1 914. 1 Table V shows the average percentages 

 of the viable seeds which were impermeable in the two tests and the 

 calculated average and maximum percentages of the seeds, impermeable 

 when freshly gathered, which became permeable in the interval of about 

 one year between the two tests. 



Table V. — Change in permeability of clover and alfalfa seeds during the first year after 



harvesting 



Kind of seed. 



Red clover. .. 



Do 



Alsike clover 



Do 



White clover, 



Do 



Sweet clover, 

 Alfalfa 



Manner of 

 hulling. 



Hand... 

 Machine 

 Hand... 

 Machine 

 Hand... 

 Machine 

 Hand. . . 

 Machine 



Number 

 of sam- 

 ples. 



220 



207 



12 



37 

 8 



5 

 6 



Average percentage 

 of viable seeds 

 which were im- 

 permeable. 



Fresh. 



92 

 17 

 91 

 1 3 

 98 

 34 

 98 

 32 



1 year 

 old. 



87 

 14 

 91 

 16 

 90 

 28 



Calculated percent- 

 ages of the seeds, 

 impermeable when 

 fresh, which be- 

 came permeable in 

 about 1 year. 



Average. 



o 



60 



Max- 

 imum. 



1 40 



26 



55 

 40 



87 



1 These calculations are based only on lots of which 30 per cent or more were impermeable when tested 

 the first time. 



The hand-hulled lots contained very large percentages and the machine- 

 hulled lots comparatively small percentages of impermeable seeds. With 

 few exceptions in the case of single lots of seed, the impermeable seeds 

 in the hand-hulled lots became permeable more slowly than those in the 

 machine-hulled lots. 



The average results for all lots showed that not more than 8 per cent 

 of the impermeable seeds in hand-hulled lots of the different kinds of 

 clover seed had become permeable during the interval between the two 

 tests; yet over 50 per cent of the impermeable seeds in one lot each of 

 hand-hulled red-clover seed and hand-hulled white-clover Sv 'd became 

 permeable. 



The case of the hand-hulled white-clover seed is especially interest- 

 ing. Eight lots averaged 98 per cent of impermeable seeds when fresh. 

 Only 1 per cent of the impermeable seeds in seven of these lots became 

 permeable in a little over a year. Of the impermeable seeds in the other 

 lot 36 per cent became permeable in two months, 45 per cent in three 

 months, and 55 per cent in 14 months. Nothing in the appearance of 

 the different lots of seed either of white clover or of the other kinds indi- 

 cated that any differences would be found in the rate at which the 

 impermeable seeds became permeable. 



1 The results of the special investigation on impermeable clover seed conducted in the fall and winter 

 of 1914-15 have been published elsewhere (10). 



