abstracts: agricultural chemistry 87 



at the Minneapolis meeting of the American Chemical Society. It was 

 pointed out that soils behave as individuals, owing to the number and 

 interdependence of the properties of the soil mass and its individual 

 components. Crop production, therefore, is the result of many factors, 

 natural and artificial, but all mutually dependent. Each of the arti- 

 ficial methods of control, tillage, crop rotation, and fertilization, affects 

 all the factors; consequently, no simple theory of fertilizer action can 

 satisfactorily explain the facts. With intensive methods of cultivation, 

 fertilizers are effective on all kinds of soils, more so on the naturally 

 better soils. Materials other than those containing the traditional 

 plant foods may become valuable fertilizers if they satisfy commercial 

 requirements. F. K. C. 



AGRICULTURAL CHEMISTRY.— Effect of a second solute in adsorp- 

 tion by soils and in leaching of soluble salts from soils. Harrison 

 E. Patten. Journal of Physical Chemistry, 15. 1911. 



A higher concentration of phosphates may be obtained when weak 

 solutions of salts ordinarily used as soil amendments (potassium chloride, 

 potassium sulphate, potassium and sodium nitrates, or potassium car- 

 bonate) are passed through the soil than can be obtained by the use of 

 distilled water alone. This effect is not simply a question of the "solu- 

 bility" of phosphate in water or in the solutions used for percolation, 

 since the volume of liquid held in contact with the soil material is in all 

 cases far greater than that required to dissolve the small amounts of 

 phosphates and of other salts present. The effect is evidently due to a 

 disturbance of the equilibrium between the soluble material retained 

 by the soil and the soil solution. This disturbance having been produced 

 the soil system tends to readjust itself, giving a very roughly steady value 

 for the concentration of the leachings with respect to phosphate. 



The bearing of this on the use of soil amendments is that it opens 

 questions as to the actual functions of different salts when added to pro- 

 mote plant growth. It appears possible that the addition of, e.g., a 

 nitrate or a chloride to the soil may benefit a plant by liberating phos- 

 phate, as well as by the addition of the salt itself for plant use. In addi- 

 tion must be considered the effects of the liberated phosphates and of 

 the added soil amendment upon the physical structure and condition of 

 the soil. H. E. P. 



