THE SOILS OF IRELAND. 31 



of nitrates and salts of ammonia, which would accrue from the cultivation of 

 leguminous crops, is the best argument for his consideration of this branch 

 of science. 



Nor have Irish soils suffered only through the dissipation of nitrogenous 

 compounds, for every barrel of wheat, barley, oats, and other cereal taken 

 to the market, every load of hay and straw sold, to be exported or utilised 

 in and near towns, every animal driven off the land, every gallon of milk 

 used elsewhere than on the farm, robs the soil of a proportion of lime, phos- 

 phate, potash, magnesia, and other mineral substances, so essential to the 

 maintenance of fertility. It is a somewhat amazing fact that after centuries 

 of such loss as must in the ways mentioned have been incurred, not to speak 

 of the still greater waste, perhaps, through the drenching of soils in wet 

 weather, and the carrying off by drainage, streams, and rivers, of thousands 

 of tons of the substances mentioned, that the soils of this country 

 should have retained any reputation for fertility. The source of waste last 

 referred to is so great, even in France — a much drier country than Ireland 

 — that M. Risler,* in his Geologic Agricole, while enforcing his advice as to 

 the necessity for irrigation, gave it as his opinion that, if this were ade- 

 quately practised, the wealth of the country would be doubled. So great is 

 the drain upon the phosphates, particularly it may be said, in the store- 

 cattle feeding portions of Ireland, that Sir R. Kane questioned whether the 

 store of these valuable substances would not, sooner or later, become ex- 

 hausted. There is no doubt that this would be the case, were it not that the 

 soils become renovated by fresh supplies from beneath, in the case of land 

 where, as over much of the limestone area, the necessity for artificial supplies 

 IS not greatly felt, though the soils are often shallow. 



The varieties of soils being practically innumerable, resort must be had to 

 some system of classification, and with it to some means of representation, 

 so as to bring into relief points of comparison between soil and soil — chiefly 

 as regards quality and ascertainable deficiencies ; although quality, the chief 

 thing with which practical men are concerned, is a comparative rather than an 

 absolute term, and is dependent upon a multiplicity of conditions. Geolo- 

 gical maps to some extent serve the needed purpose ; they fix the localities 

 of rocks whence the soils are derived, and thus afford clues to soil qualities, 

 and an intelligible basis of effective classification. 



Throughout wide areas in Ireland, the rock is covered with detritus not 

 wholly derived from the solid mass immediately beneath ; and both this 

 covering and the solid rock, are concealed in many places by more recent 

 deposits of alluvium, bog, blown sands, etc. There are, however, many areas 

 of importance chiefly in the hilly tracts, where locally formed clay soils are 

 found. Throughout the central plain, and in Connaught, where limestone 

 appears here and there in the low ground, this rock is covered with a scanty 

 soil, proverbially rich. It is well suited to store-feeding pasturage, in conse- 

 quence of the quantity of lime and lime phosphates which are set free by 

 solution, and are taken up in extra quantity by the grass and meadow hay. 



The soil yielded by the disintegration of the limestone varies in physical 

 character, from light yellowish brown tenacious clay loam, to a brown friable 

 sandy loam, according as the limestone contains little or much admixture of 

 sand, or beds of sandstone. Some of the best feeding land of Connaught 

 is of the former character — the strong clay containing a fair proportion of 

 potash as well as phosphates. 



* Director of the Institiit Agronomiqne, Paris. 



