58 



Depth of Sowing Grass and Clover Seeds. [Apr., 



to the veiy shallow depth of J. in. had the effect of increasing 

 the number of surface seedlings by more than 100 per cent. 

 It is also equally clear that only faibires in " take " may be 

 expected when the seeds are covered to depths of 2 or 3 in. 

 since at 2 in. only 53 per cent, reached the surface while the 

 3 in. depth gave only 6 per cent, of surface seedlings. 



These experiments show that the best results are obtained when 

 the seeds are buried to a depth of not greater than 1 in. To 

 ensure that the seeds are properly covered a method of covering 

 by wTiich the seeds are buried to average depths of J in. to J in. 

 siiould be jidopted. Moreover, the young seedlings will not run 

 so mjich risk of being killed off as a result of a sudden spell of 

 dry weather at these depths as they would if covered too lightly. 

 Although J in. to J in. beds gave heavier yields than the J in. 

 and f in. beds in a very wet season, it is highly probable that 

 these yields would be reversed in a normally dry year. 



It appears from the following figures, which give the average 

 number of stems per plant at about eight months after sowing, 

 that surface and deep sowings (e.g., 1 in. and 2 in.) have a 

 detrimental effect on stem formation during the early stages in 

 the life of the plants : — 



Depths ... ... Surface ^in. | in. ^ In. 1 in. 2 in. 



Nuu.ber of stems per })lat.t 2-2 3-0 2 8 K.-2 2-G 2-4 



The Causes of Failure of Surface Sowings. — When the red 

 clover seeds are left uncovered the thick radicles of the seedlings 

 are unable to enter the soil immediately germination takes place. 

 This is partly due to the very blunt nature of the root tips 

 and partly to the fact that the root hairs are too short and matted 

 to act as such efi&cient organs of anchorage as in the case of 

 certain of the grasses. As the radicles and hypocotyls increase 

 in length the seeds are pushed back often to a distance of IJ in. 

 ])efore any of the seedlings become fixed, but if the seeds are 

 held in position by a light covering of soil the radicles are able 

 to force their way into the soil at once. That this is the case 

 was proved by the follovving experim^ent. Seeds were sown on 

 the surface in four pots. The seeds in two of the pots were 

 lightly pegged dov/n by means of notched m.atchsticks, the other 

 two pots were kept as controls. The results 10 days after sowing 

 are given below : — 



Pegged 

 Unpegged ... 



Percentage 

 Germination. 

 95 

 92 



Percentage seedlings with 

 radicles fixed in the soil. 



84 

 4 



