34 



THE SOILS OF IRELAND. 



clay loams, would be noted ; and, as regards chemical resources, distinctions 

 would be indicated between lime soils, highly calcareous, and non-calcareous 

 soils, and those strongly potassic. The former or -physical distinctions, 

 might be indicated respectively by the following letters, viz. : — s (sands and 

 gravels) ; cl (brick clays) ; Is, I, Ic (the principal varieties of loam). Tabu- 

 lated, the chemical indications, also, might appear as follows : — 



Classificatio.m of Soils according to their Chemical Properties. 



Such a classification as this would place experiments in manuring upon a 

 sound, because scientific basis ; for it will be apparent to any thoughtful 

 person that the results obtained from the use of certain manures upon soils — - 

 say, of the first and fourth kinds named above — must necessarily differ ; 

 and that without a recognition of the distinctions pointed out, the results 

 should prove misleading and worthless as a means of testing or illustrating 

 the comparative value of manures. The results obtained may just as well 

 prove the differences of sot/s, in different places, as the different degrees of 

 suitability of various schemes of manuring, to certain crops. It may be 

 conceded that crops do not all draw alike upon the chemical constituents of 

 soils — upon this fact partly the principle of rotation cropping depends — and 

 that certain artificial supplies are suggested by the special requirements of 

 particular crops. It is, nevertheless, rational to suppose that the deficiencies 

 and natural resources of soils are amongst the chief points to be considered 

 in prescribing and adopting suitable manures. Some ;^300,ooo worth of 

 mineral manures is employed in Ireland ; such are used with substantial 

 profit in many cases, but with recorded loss in others — to the extent, some- 

 times, of £2 an acre. To obviate waste some such classification as that 

 above proposed, and soil maps prepared accordingly, would seem to be 

 necessary economic desiderata. 



It has been fully established by experiments conducted at Rothamsted, 

 that the influence of certain mineral substance'=' in soils, upon the character 



