180 SOWING. 



which shows the necessity and advantage of shallow 

 sowing: it is this wheat is sowed, and sometimes 

 late, in the autumn; if immediately after the plough, 

 much of the seed falls too deeply and closely together 

 between the furrows. The seminal roots are, of course, 

 first put forth, the points of the first leaves appear 

 above ground ; but the winter sets in, before the 

 coronal roots are produced, and consequently the plant 

 is only sustained by the first roots, and through that 

 slender stem, , Fig. 50 C, amid all the changes and 

 rigours of a winter's frost and snow. The coronal 

 roots do not appear before the end of February or 

 beginning of March, (the proper time for top-dress- 

 ing wheat,) and all the time previous to this taking 

 place, and during the severe season, the plant is in 

 jeopardy as well from alternate frost and thaw, as from 

 wire-worm, slugs, and insects in the soil. But in the 

 case of sowing at the proper depth, the seminal roots 

 are in their proper place, and are there much stronger; 

 and granting that the secondary roots are not put forth 

 till the spring, the plant has not that slender canal 

 exposed to the attacks before alluded to. 



With respect to the proper depth for smaller seeds, 

 if they be but just covered so as they receive at the 

 same time a moderate share of the moisture always 

 more or less present in mellow soils, it is enough ; 

 one tine of the harrows in the field, and the smoothing 

 action of the rake in the garden are all that are necessary 

 for the generality of small seeds. Some very diminu- 

 tive seeds only require to be pressed into the surface ; 



