SECTIONAL TRANSACTIONS.— M. 409 



within it. Hitherto there has been too great a tendency to consider the soil statically, 

 and to try to visualise its constitution as a fixed thing. 



Immature, Cultivated and Sedimentary -rock Soils. — -In soils which are immature 

 and in which the soil processes have not had full play, some of the characteristics of 

 the parent material still obtain. The characterisation of such soils involves a com- 

 bination of the two considerations, namely, the parent material and the processes 

 acting upon it. 



In cultivated soils the upper part of the natural profile is disturbed by cultivation 

 processes which prevent the formation of horizons within the depth of their influence, 

 and tend to make the soils uniform. This disturbance of the upper horizon or 

 horizons may have considerable effect upon the lower horizons. 



Soils which are formed from sedimentary rocks such as the clays and sands of this 

 country will not, under uniform weathering conditions, ultimately become alike in 

 all respects. The rocks from which they are formed are the results of a sorting-out 

 process in which the larger particles have been approximately separated from the 

 smaller ones. 



It may be thought that the considerations underlying the genetic classification of 

 soils are of less importance in all these cases and, therefore, of less importance in this 

 country. There is, however, a sense in which those considerations are of greater 

 importance in the study of such soils. Crudely speaking, the soil processes have gone 

 on to the utmost in the mature soils, and the processes are easily discovered by the 

 examination of the soil. In the immature and cultivated soils the processes are 

 going on and the soil itself does not so clearly indicate what these processes are. But 

 the knowledge of these processes is equally important ; indeed, it is fundamentally 

 important. The study of the soil-formation processes is much more difficult in a 

 country of immature and cultivated soils than in a country of mature soils, but it 

 cannot possibly be less important. 



Dr. W. G. Ogg. — The Soil Profile as a Basis for Intensive Soil Surveying. 



It is now generally agreed that the broader grouping of soils is most satisfactorily 

 based on climatic factors. These find expression in the soil profile and boundaries 

 between the great climatic types can be decided by an examination of the profile. 



There is not, however, the same consensus of opinion on the question of intensive 

 surveys. 



Minor modifications of the profile occur within each of the broad climatic types. 

 These may be due to the parent material (origin, method of deposition, &e.), topography, 

 drainage, and other causes. There appears to be no reason why these minor profile 

 differences should not be used in field mapping, and there seems to be every kkelihood 

 that a system which takes account of the whole profile will yield more useful results 

 than those which take account of a single character or a single layer. Vegetation 

 differences have been found to be closely linked up with differences in the profile and 

 without changing the basis of mapping, the vegetation may be used to facilitate the 

 fixing of profile boundaries. 



It is probably too soon to attempt to evolve a scheme of classification for intensive 

 work. Mapping, however, can be carried out and the profile differences found should 

 be described with explanations, where possible, of the features observed. The amount 

 of detail will, of course, depend on the scale of mapping. 



There is urgent need at present for the definition of texture and colour and 

 standards to be employed in field work, and also for the clearer definition of such 

 terms as soil ' type,' ' variety,' &c. 



Mr. W. Morley Da vies. — I fee.l that the remarks of Prof. Hendrick are of con- 

 siderable importance. In an area as small as Britain, with similar climatic and 

 agricultural conditions, concordance as to method seems to be essential. Furthermore, 

 I agree with Mr. Morison that the practical side of the question cannot be totally 

 disregarded. The needs of the agriculturist, standing as they do at present, necessitate 

 that this interest should be in the mind of the surve3 r or when deciding on a scheme of 

 survey. 



It would be a pity if the meeting obtained the opinion that the methods suggested 

 were all at variance. As a matter of fact, considerable uniformity holds, everyone is 

 agreed as to the essential data to be collected. It is in the fashion that this data 

 should be presented where a difference of opinion is apparent. It is probable that 

 this difference will gradually disappear when co-ordinated work brings the individuals 

 involved together, with an opportunity for discussion in the field, as distinct from the 

 conference room. 



