510 On the Growth of Barley hy different 3Ianures, Sfc. 



which several of the leguminous crops (especially clover) — and 

 also wheat and oats — penetrated, was very remarkable. It may 

 be mentioned in passing, that of the specimens traced out in the 

 experiments then made, one clover plant was for a length of 

 time preserved with roots nearly 6 feet in length, the successful 

 extrication of which, through their numerous wendings, was the 

 result of the tedious labour of many days. It is to be regretted 

 that the perfect series of specimens was not preserved as such, 

 or at least perpetuated by drawings as a means of useful illus- 

 tration for others. 



But to recur : when considering tlie results of field experiments 

 on wheat, we have directed attention to the fact, that the success 

 of the autumn-sown crop was gi'eatly dependent upon the pro- 

 gress of the under-ground development during the early months 

 of growth. It was held that this was very much favoured, other 

 things being equal, by a liberal supply of available nitrogen 

 within the soil, and that thus, the range of collection of the 

 fibrous feeders of the plant was so extended as to render avail- 

 able, when needed in the after stages of growth of the plant, the 

 mineral constituents of a much larger area of the soil, than other- 

 wise would be the case. Very different are the usual conditions 

 of the growth of barley. Instead of winter-growth, and a com- 

 pressed soil, tending to increased depth and area of root distribu- 

 tion, we sow our barley in the spring, work the staple shallow, 

 and keep it as light and open as possible. Under these circum- 

 stances of short time, rapid growth, and comparatively limited 

 depth and area of root development, we find the direct supply 

 of some of the rarer, but essential mineral constituents of our 

 soils, much more efficient with the barley crop than with wheat. 



The mechanical conditions of soil, and the season of growth of 

 the barley crop, are in many respects more like those required 

 by the turnip ; and they are calculated to favour the distribution 

 of a large amount of fibrous root near the surface, rather than any 

 considerable development in the lower layers. In our paper on 

 'Turnip Culture,'* it was shown how much this distribution 

 of surface root-fibres was increased by the use of superphosphate 

 of lime. The same is the case with barley. It is obvious, that 

 with this multiplication and more thickly distributed net-work 

 of root-fibres, 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 certain important con- 

 stituents within a limited area, enables the plant to provide 

 itself more freely and rapidly with others it may require. 



Whilst on this point it will not be out of place, in defect of 



* Journal of Eoyal Agricultural Society, vol. viii., 1847. 



