OF THE RED CLOVER. 277 



to wliicli the roots do not extend. Undei- tliese circum- 

 stances, it is not to be wondered at that the soil sliould be 

 sooner uniitted for the gTowth of some crops than for others ; 

 and e>pecially for those crops which require a larger amount 

 of those substances which, in the first instance, exist in the 

 soil in more limited quantities, or which are more soluble, 

 and carried away br rain to a depth beyond the reach of 

 their roots. ^ This is, perhaps, more the case with red 

 clover than any other plant, which will be more apparent 

 when we avail ourselves of the aid that chemistry atfords. 

 It tells us, in the first place, that 1,000 lb. of red clover, in 

 the dried state, according- to the analysis of Sprengel, contain 

 the following- proportions of inorg-anic matter : — 



Potash 19.95 



Soda 5.29 



Lime 27.80 



INIagnesia 3.33 



Alumina 0.14 



Silica 3.G1 



Sulphuric acid 4.47 



Phos]ihoric acid 6.57 



Chlorine 3.62 



From this analysis, we learn the very large proportion of 

 potash which red clover abstracts from the soil, when con- 

 trasted with the other crops with which it is generally asso- 

 ciated in the course of a regular rotation. 



WTieat contains in 1,000 



lb. of the grain 2.25 Stra«-, 1,000 lb 2.45 



Bariey 2.27 — 1.80 



Oats 15.0 — 8.70 



Rye-grass hay — — 8.81 



If v/e allow that the straw is double the weight of the 

 grain, then in 1,000 lb. 



Of wheat, there is only 0.89 of potash. 



Of barley " 2.13 — 



Of oats '. 6.30 — 



Thus we see that 1,000 lb. of red clover requires nearly 

 as much potash as is contained in twenty times the same 

 amount of wheat, eight times the amount of barley, and 



' See Professor Johnston's Lectures on Agricultural Chemistry, p. 205. 



