No. 2, June, 1921] SOIL SCIENCE 221 



results of fertilizer experiments at the Ohio and Pennsylvania agricultural experiment sta- 

 tions. Study of the Ohio data shows significant increases in yield on "two-element" and 

 "three-element" plots, but not on "one-element" plots. The authors conclude that, even 

 with the best methods, our present knowledge of the enormous variability of all soils and 

 plants render the data from any given fertilizer plot of value only on that plot, and renders it 

 highly probable that no fertilizer experiment as ordinarily conducted is possessed of sufficient 

 practical value to justify the large expenditure of money, time, and energy involved. — 

 Howard B. Frost. 



1525. Maquenne, L., et E. Demoussy. Sur la richesse en cuivre de terres cultivees. 

 [The amount of copper in cultivated soils.] Compt. Rend. Acad. Sci. Paris 169:937-942. 

 1919. — The purpose of the work undertaken was to determine whether or not the copper in- 

 troduced in soils by use of copper sprays may become injurious to plants. Samples (140) of 

 vineyard and other soils were analyzed and the amount of copper was found to vary from less 

 than 1 milligram per kilo to as much as 250 milligrams in some cases. The amount of cal- 

 cium did not appear to have any direct bearing on the amount of copper retained by soils, 

 but various soils were variable in their retaining power. In general, vineyard soils which 

 had been subjected to copper sprays over a long series of years were found to contain the 

 greatest amounts of copper. Most of this copper is retained in the first 0.3 meter of soil. 

 Observations on the amount of copper taken up by plants and on the amount of soluble cop- 

 per in the soil lead to the conclusion that the copper of cultivated soils is not injurious to 

 plants. — V. H. Young. 



1526. IMasoni, G. La reazione alcalina provocata dagli acidi nelle terre in rapporto alia 

 nutrizione delle piante. III. Solubilizzazione dei fosfati nel terreno. [The relation to plant 

 nutrition of the alkaline reaction brought about by soil acids. III. Solubility of phosphates 

 in the soil.] Staz. Sperim. Agrarie Ital. 53: 121-137. 1920. — A continuation of researches 

 brought to bear on the question of the complex chemical reactions in the soil, the making 

 soluble of substances insoluble in water, and plant chlorosis. Various mineral or organic 

 acids were allowed to act upon the insoluble phosphates in the presence of an excess of CaCOs. 

 The acids used were hydrochloric, nitric, sulphuric, formic, acetic, oxalic, succinic, malic, 

 tartaric, and citric. The influence of the temperature upon the various changes was also 

 studied and it was found that, especially when water was used alone, the solubility of 

 Ca3(P04)2 was enhanced by a rise in temperature. The principal result of these investiga- 

 tions is to be found in the fact that in the presence of an excess of CaCOs the acids which left 

 more phosphorus in solution were citric and malic, while the stronger acids left smaller quan- 

 tities of this element in solution. These results are similar to those the author obtained when 

 manganese and iron salts were used instead of calcium compounds. The behavior of the 

 different acids the author ascribes to the OH ion developed, through their interaction with the 

 calcium carbonate, and the influence of this upon the mono or dicalcium phosphate in solu- 

 tion and the resulting precipitation of the tricalcium salt. The presence of this OH ion is 

 regulated by (a) the strength of the acid, and (b) the temperature at which the action takes 

 place. It is concluded that the phenomenon of calcareous chlorosis affecting various species 

 of plants grown on a calcareous soil, to a different degree, may be not only dependent upon 

 a lack of iron but also of phosphorus. — A. Bonazzi. 



1527. Mount, H. A. Fuel or fertilizer? Sci. Amer. 123:498, 509-510. S fig. 1920.— 

 A discussionof America's little-known peat bogs and their present utilization. — Chas. H. Otis. 



1528. Opazo, Roberto. Aplicacion de la cal a los terrenes de cultivo. [Application of 

 lime to cultivated soils.] El Agricultor [Santiago, Chile] 5: 48-51. 1920. 



1529. Sebelien, John. Modern methods for experiments with fertilizers and manures. 

 Jour. Agric. Sci. 10:415-419. 1920. — The extreme variation between trial plots, amounting 

 in some cases to as much as 100 per cent under the same treatment, leads to the conclusion 

 that ordinary field plots are of little scientific value in studies with fertilizers and manures. 



