Soaking of the seed, which has often been recommended for Hght soils 

 when tlie time for seeding lias been continuously dry, should be used with due 

 care. If the weather becomes dry and the water which has been taken up in 

 swelling is not enough to make the primar}- rootlets grow into the soil, then 

 there is an unavoidable interruption in growth. This is the explanation of 

 WoUny's discovery^ that soaking produces plants maturing later. 



Wollny's^ studies on the suitable dei^th of sowing are most thorough ; 

 he determined for grain tliat sowing 2 to 3 cm. deep furnishes the 



Fig. 9. Rye seedling- with too deep sowing of the seed grain. Klevation of 

 the node of the sprout near the surface of the soil. (Orig.) 



best results in yield. Over and above this a noticeable retrogression is found 

 already especially emphasized by Jorgensen\ The last named author 

 also found rye to be the most sensitive and wheat the least sensitive. For 

 most of the Leguminoseae the depth of the sowing is less important. In con- 

 trast to this, varieties of clover and rape have been proved very dependent 



1 Bot. Centralbl., Vol. XXX, No. 15, 1SS7, p. 48. 



- Wollny, Saat und Pflege der landwirtschaftl. Culturpflanzen. Berlin, 1885. 

 3 Jorgensen, S., Versuche liber das Unterhringen der Saat etc. Annalen d. 

 Landw. in d. Kgl. Preuss. Staaten. Wochenblatt 1873. No. 11. 



