SECTIONAL TRANSACTIONS.— M. 407 



Tuesday, September 6. 



Morning. 



Discussion on Soil Surveys. Sir John Russell, F.R.S. ; Prof. G. W. 

 Robinson ; Prof. J. Hendrick ; Prof. N. M. Comber ; Dr. W. G. 

 Ogg ; Mr. W. Morley Davies. 



Sir John Russell, F.R.S. — Soil surveys are an old activity of British agricultural 

 experts, the first having been made at the end of the eighteenth century by the 

 simple method of inspection ; the purpose was to obtain information as to the 

 existing state of agriculture and to offer suggestions for improvement. No other 

 general survey was made until after 1894, when the present system of agricultural 

 education came in ; it was then conducted on wholly different lines. The Rothamsted 

 experiments had emphasised the importance, for crop production, of nitrogen, 

 potassium and phosphorus ; chemists had developed methods for estimating the 

 amounts of these in the soil, and for forming an estimate of the probable response 

 of the crop to fertilisers. The staffs of the Colleges carried out fertiliser experiments 

 which met with considerable success : the idea developed of making soil surveys 

 which would help the farmer in his fertiliser practice and soil management generally. 

 Thus, the British surveys were from the outset intended to describe the soil as a 

 medium for crop production ; the analytical work was directed to the discovery of 

 the amount of plant nutrients present and the depth of sampling was fixed at 0"-9" 

 for the surface layer, and 9"- 18" for the lower layer, these being regarded as average 

 root ranges for shallow and deep-rooting crops respectively. The American surveys 

 were on essentially the same lines : they were started in 1860 to afford guidance for 

 the development and improvement of agriculture and they were based on the view 

 that the soil was a prime agent in crop production. Through the influence of Milton 

 Whitney, and probably resulting from his early interest in the tobacco crop, which is 

 profoundly affected by soil type, the American workers attached more importance 

 to mechanical analysis than to the estimation of plant nutrients. Hall and Russell 

 combined both methods and studied soil type as well as chemical composition. 



Meanwhile the Russian workers were studying the soil quite apart from its crop- 

 producing power. They, like the British workers, had laid out fertiliser experiments 

 which were under the charge of Mendeleeff, then in his youth ; but these experiments, 

 unlike the British, had given negative results, so that they were given up and Mendeleeff 

 returned to pure chemistry, to discover the Periodic Law. But they had shown the 

 importance of soil types, and the Free Economic Society which had fostered them 

 invited Dokuchaiev to study the chernozem. He ignored agricultural considerations 

 entirely and studied the soil simply as a distinct natural object, restricting himself 

 also to its morphology, with results now known through the writings of Glinka. He 

 was followed by a number of Russian workers who have made soil morphology 

 essentially a Russian subject ; their work has had considerable influence in Britain 

 and America. 



The British workers had long recognised that soil analysis could at best only afford 

 comparisons of one soil with another, and they had studied numerous methods of 

 describing the soil. They had, however, retained the two depths, 0"-9" and 9"- 18". 

 The Russian workers frankly discarded any connection with crop producing power, 

 and showed that inspection of the profile gave a much more rational indication for 

 the depth of sampling. 



In practice the soil surveyor in Britain is compelled to cover a moderately largo 

 area of land and the soils do not as a rule fit in with any of the Russian groups ; they 

 are influenced more by the nature of the parent material than by the climate. Con- 

 sequently the geological map affords the best basis of surveying, especially for all 

 formations down to the Devonian, though for the lower ones it appears less useful. 

 The boundaries do not quite agree with those of the geologist because of local slipping 

 or drifting, and in regions of much drift the geological basis may lose much of its 

 significance. The surveyor records the general nature of the ground, its configuration, 

 stoniness and state of drainage, also the colour, texture and reaction of the soil; 

 these particulars are recorded for the various layers down to the underlying rock. 

 Soils of similar appearance are mapped similarly, but in practice mapping is often a 

 difficult operation. Useful guidance may be obtained from a study of the vegetation 

 of the different areas. 



