328 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



VOELCKER ON SOILS. 



Mr. Vbelcker, an eminent agricultural chemist, delivered a 

 lecture before the Chemical Society of London upon the pro- 

 ductive power of soils in relation to the loss of plant-food by 

 drainage, in which he took occasion to refer to the inutility, 

 for most purposes, of the analysis of soils, as ordinarily con- 

 ducted. He states that there are many apparently similar 

 soils that is, soils in which analysis shows like quantities of 

 the same constituents which differ widely in their produc- 

 tive powers, owing to the fact that the indications are of ulti- 

 mate composition instead of showing states of combination 

 in which the ingredients exist in the soil. 



Another consideration of importance is that soil analyses 

 throw no light upon the physical or mechanical conditions 

 which affect the fertility of land. The productiveness of 

 land is much influenced, too, by the character of the subsoil 

 and its composition in relation to the surface-soil, of which a 

 soil analysis conveys no information. Again, meteorological 

 conditions, such as the aspect of the field, the prevailing wind, 

 the amount of rain, and the distribution of the rain-fall in 

 the year, are all of the utmost importance in farming, and 

 are, of course, not indicated by any analysis. 



Dr. Voelcker, however, would not be considered as regard- 

 ing such analyses as of no value, since in many cases quite 

 the contrary is the fact. For instance, it is easy to deter- 

 mine whether a soil is deficient in lime or not, and thus as- 

 certain whether it is proper to impart a dressing of this min- 

 eral. It is also known that potash salts may be applied with 

 great advantage on some soils, while on others their fertil- 

 izing effects are scarcely perceptible ; and the determination 

 of the question whether there be enough potash in the soil 

 will enable us to decide upon the proper action in this re- 

 spect. 



Again, it is possible to ascertain, by finding whether there 

 is potash in clay, as to its being benefited by burning; burnt 

 clay being an excellent fertilizer if the clay contains unde- 

 composed silicates of potash; but the expense of this process 

 would be entirely wasted if the clay be naturally poor in al- 

 kaline silicates. Again, peaty soils are often completely bar- 

 ren, this condition being due, in most cases, to the presence 



