ASSOCIATION OF COLLEGES AND STATIONS. 195 



soils of New Englaiul are in special need of potash, and that it is 

 impossible to determine the fertilizer requirement of a soil apart 

 from the peculiar needs of the particular crop to be grown, a fact 

 which was strontrly emphasized by other speakers. 



A paper by Mr. A. M. Peter on Some Results of an Old ^fethod for 

 Determining Available l*lant Food in Soils was read by the secretary 

 of the section. 



Director C. E. Thome presented a paper on Soil Investigation, in 

 which he pointed out the necessity of supplementing chemical analysis 

 and pot experiments with carefully conducted field experiments, and 

 also of giving more attention to the biological processes in the soil. 

 The results of a 7-year rotation Avith corn, oats, and wheat, and of a 

 8-year experiment with clover, at the Ohio Station, using lime and 

 various fertilizer combinations, were reviewed, showing that phos- 

 phoric acid is apparently the first requirement of cereals on the soils 

 experimented with, and lime the first requirement of clover, potash 

 being second in importance for this crop. The beneficial eifect of the 

 lime, particularly on the clover crop. Avas apparently due to the acid 

 condition of the soil, the character of the growth of the clover being 

 a reliable index of the acidity and the need of lime. Such acid soils 

 were shown to be widely distributed in Ohio. 



Discussing this paper. Dr. J. G. Lipman urged the importance of 

 more careful study of the relation of acidity to bacterial activity on 

 the one hand and to the physiological processes of the plant on the 

 other, and Dr. H. J. AAHieeler made some suggestions regarding profit- 

 able lines of research in connection with soils. 



In the discussion of the subject of demonstration work. Director 

 Thorne explained the Ohio system of (1) test farms on which experi- 

 mental work is carried on in different parts of the State; (2) coopera- 

 tive experiments with farmers, taking up simpler phases of station 

 work, and intended primarily to develop farm experimenters in each 

 locality, and (3) special arrangement for particular pieces of work. 

 The importance in cooperative work of relieving the farmer from 

 pecuniary responsibility and of maintaining strict sui)ervision of 

 the woi-k through station officers was pointed out. The speaker urged 

 tlie need of extension of demonstration work. 



Doctor Hopkins ex])lained the system of coml)ined ex[)erimental 

 and demonstration work followed in Illinois on the farms controlle(l 

 l>v long-time lease or pur(;hase on the various typical soil areas of that 

 State. Prof. L. C. Corbett (hvw a sharp distinction between experi- 

 mental work and demonstration work, holding that the latter should 

 have as its prime object the teaching of remunerative methods of 

 farming, as illustrated in the work of the De|)artment demonstration 

 farms in the cotton belt. Simihir views were expressed by Director 

 C. D. Smith, who cited various illustrations of wavs in which the 



