SOIL ADAPTED TO THE OAT CROP. 225 



of very great importance, and should not be overlooked in 

 treating of the economy of the plant. Having thus glanced 

 at the peculiarities of the best, and at the moderately good 

 soils for the oat crop, let us do the same office for those 

 not so adapted. 



25. As the soil from the alluvial deposit of the trap and 

 new red sandstones may be looked upon as the best and 

 most fertile for the oat crop, so may the soil, composed of 

 " loose calcareous matter," be looked upon as the most 

 sterile. Of this class are the upper chalks of England, 

 incliosavi sands and gravels. Mr. Haxton, in treating of 

 this class of soils, draws attention to the fact that it has 

 been frequently remarked that in the case of light soils, 

 which have been long under cultivation,, a second applica- 

 tion of lime, if not positively injurious, is at all events not 

 beneficial to the oat crop ; indeed, that an " overdose of 

 caustic lime, or of purely calcareous chalk, is frequently 

 productive of the worst results." He names instances 

 where light gravelly soils were rendered incapable of grow- 

 ing oats for a long time through having been top-dressed 

 with a rich calcareous shell marl found in beds underlying 

 peat. On all light soils composed principally of gravel, 

 sand, loose brown earth, or decomposed peat long under 

 cultivation, lime should be sparingly used, as an overdose 

 is always fatal to the success of the oat crop. The same 

 effects of an overdose of lime are not observable, it is right 

 to state, in deep alluvial soils, whether these be made up of 

 clay, loam, or of black mould. Loose, mossy, or gravelly 

 soils, which have been long under cultivation, are, accord- 

 ing to the experience of this authority, always the worse 

 of liming ; and the point is all the more worthy of obser- 

 vation, as on the first of these, namely, mossy or peaty soils, 

 oats, as we have before stated, is the only cereal crop which 

 can be cultivated. Of course, in the primary treatment of 

 peaty or mossy soils liming is essential, in order to act- 

 upon the inert vegetable matter, and neutralize or bring 

 into good action the acids with which it abounds; but as 

 soon as the soil is fairly formed by liming and by proper 



