122 EXPERIMENT STATION" RECORD. 



iron in the presence of a large amount of lime. A mere high percentage of lime 

 in the ash does not induce chlorosis. 



" Chlorotic leaves are lower in nitrogen and oxidizing enzyms than green 

 leaves, due, probably, to the degeneration induced by the lack of iron. 



" Strong light increases the chlorosis by the more rapid destruction of the 

 chlorophyll." 



Effect of soluble salts on the absorption of phosphates by soils, H. E. 

 Patten {Jour. Pliys. Chem., 15 {1911), No. 7, ijp. 639-658, figs. 6; ahs. in Jour. 

 Soc. Chem. Indus., 30 {1911), No. 22, p. 1325). — The author reports the results 

 of experiments to determine the effect of various salts on the quantity of 

 phosphate soluble in soils treated with calcium monophosphate (350 lbs. of 

 superphosphate per acre). Quartz and two soil types, one a sandy soil and 

 the other a fine clay, were used as the absorbing bodies. Reference is also 

 made to previous bulletins from this Department on the absorption of soluble 

 bodies from solution by soils, and the work of Van Bemmelen on this subject 

 is briefly reviewed. 



From the results of these studies the author concludes that apparently " a 

 higher concentration of phosphate may be obtained when weak solutions of 

 salts ordinarily used as soil amendments (potassium chlorid, potassium sul- 

 phate, potassium and sodium nitrate, or potassium carbonate) 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 ' solubility ' of phosphate in 

 water or in the solutions used for percolation, since the volume of water 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 and rearrangement of the equilibrium 

 which exists or tends to exist between the soluble material retained by the soil 

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

 these soil-amendment salts again tends to readjust itself, giving (very roughly) 

 a steady value for the concentration of the leachings. 



" The absolute values of phosphate concentration in the various percolates 

 are not to be taken as representing what would be obtained under field con- 

 dition with these soils. The values are good only in the particular experimental 

 environment and in comparison with each other; and even then are likely to 

 be misinterpreted if one neglects the percolation rate and the irregularity of 

 soil-percolation conditions. The effects of the liberated phosphates and of the 

 added soil-amendment salt upon the physical structure and condition of the 

 soil must likewise be considered. These effects are generally of considerable 

 magnitude, and frequently so complicated that it is impracticable to predict 

 their direction a priori." 



The soil solution, F. K. Camekon {Easton, Pa., and London, 1911, pp. Y+ 

 136, figs. 3). — The purpose of this book is to show the importance of study, to 

 point out the line of attack upon the problems, to make available for students 

 of agriculture a systematic outline of the work so far accomplished, and in the 

 main to encourage the further acquisition of knowledge in soil chemistry. 



The material brought together has been presented to the faculties and stu- 

 dents of several agricultural colleges in the form of a short course of lectures 

 and has already been published (E. S. R., 23, p. 714). The different chapters 

 treat of the soil, soil management or control, soil analysis and the historical 

 methods of soil investigation, the plant-food theory of fertilizers, the dynamic 

 nature of soil phenomena, the film water, the mineral constituents of the soil 

 solution, absorption by soils, the relation of plant growth to concentration, the 

 balance between supply and removal of mineral plant nutrients, the organic 

 constituents of the soil solution, fertilizers, and alkali. 



