EFFECT OF DEPTH OF COVERING SEED 



621 



From this table it is evident that there is a wide range in the total 

 number of seedlings produced by different depths of sowing, but very 

 little difference in the number of firsts. Thus the total number pro- 

 duced by covering ^ inch is only half as great as from ^ inch, but 

 the number of firsts is 4/5 ; that if it is admitted that the best criterion 

 of the quality of stock is the number of firsts, fhen ^ inch is the best 

 depth of sowing; that yellow pine shows great adaptability. Very 

 nearly the same number of firsts per foot of drill were produced by all 

 depths of sowing, in spite of a variation of nearly 100 per cent in the 

 total number of plants from shallow and deep sowing. 



The firsts from the different depths of sowing were of the same 

 average size and quality. 



The optimum depth in case of spring sowing is thus J/2 inch ; sowing 

 to y^ inch also gives good results. Shallow sowing (^ inch and y^. 

 inch) is 80 per cent as effective as deeper sowing. 



Jeffrey Pine 



For Jeffrey pine it was found that germination starts only five 

 days earlier with shallow-sown seed; that the peak of germination is 

 the same for all lots; that seed sown 'to ^ inch and ^ inch may be 

 considered as one group (No. 1), as may that sown to % inch and 1 

 inch (No. 2) ; that the total germination of group No. 1 is 50 per cent 

 higher than for group No. 2 ; that the deeper the sowing the higher the 

 per cent of total germination in the period of active germination. 



The real test of the value of different depths of sowing is the 

 number of firsts per foot of drill produced. This is shown in Table 4 : 



