SOILS SUITABLE FOR BARLEY. 197 



mers as to the beet rotation to be adopted in the case of 

 any crop, and however much men may disagree as to the 

 details, still all must, we think, unhesitatingly coincide with 

 Mr. Lawes and with Dr. Gilbert when they urge the " ne- 

 cessity of considering the various habits and conformation 

 of the different crops of our rotations in relation to their 

 sources of growth;" and agree with them in this also, 

 " that the important bearing of such considerations in 

 modifying the conclusions to which a more purely chemical 

 view of the offices and province in a system of manuring 

 of the various constituents would lead, is one of the first 

 lessons which the progress of field experiment teaches." 

 These celebrated agricultural authorities point out very 

 clearly the conditions of growth of the barley, and which 

 we here epitomise. The autumn crop of wheat depends 

 greatly for its success upon the progress during' the early 

 months of its growth on its underground development. 

 Other things being equal, this development of root is greatly 

 favoured by a liberal supply of nitrogen within the soil ; 

 and that this being supplied, the range of feeding ground, 

 so to term it, of the fibrous roots, was so extended, that the 

 mineral constituents of a much larger area of soil than 

 would have been otherwise the case were rendered avail- 

 able, when needed, in the after stages of the plants. The 

 case is, however, very different with the barley crop ; here 

 winter-growth and a compressed soil, which tend to increase 

 depth and area of root-distribution are not present or de- 

 siderated; on the contrary, we have spring growth, the 

 staple of soil shallow, light, and open. Under these cir- 

 cumstances, and a limited period of growth, we find the 

 " direct supply of some of the rarer but essential mineral 

 constituents of our soils much more efficient with the bar- 

 ley crop than with wheat." With the multiplication and 

 thickly-distributed net-work of roots, which we have shown 

 to be the characteristic feature of the underground develop- 

 ment of the barley, " the greater must be the resources of 

 the plant within its comparatively limited period and area 

 of growth." Thus it is that the increased supply of cer- 



