124 EXPEEIMENT STATION RECOED. 



bacterial respiration is intensified by applications of various substances to the 

 soil according to the character of the bacteria present. Those soils showing 

 low bacterial activity are likely to be most benefited by applications of nitrates. 

 If applications of monocalcium phosphate and potassium chlorid increase the 

 production of carbon dioxid this is an indication that the soil is deficient in 

 assimilable phosphoric acid and potash. 



Toxic effects of " alkali salts " in soils on soil bacteria. — II, Nitrification, 

 C. B. LiPMAN ( CentU. Bakt. [etc.], 2. AM., 33 {1912), No. 11-U, pp. 303-313, 

 figs. 2). — This is a second communication on this subject, the first (E. S. R., 

 26, p. 322), dealing with the effect of the alkali salts on ammoniflcation. 



Summarizing his results, the author concludes that " nitrification in soils 

 is inhibited by the presence of certain amounts of each of the ' alkali salts ' 

 sodium chlorid, sodium sulphate, and sodium carbonate. Sodium carbonate 

 is the most toxic, sodium sulphate the least toxic, and sodium chlorid occupies 

 an intermediate position. The actual points at which these salts become 

 markedly toxic toward nitrification in soils are at about 0.025 per cent sodium 

 carbonate, 0.35 per cent sodium sulphate, 0.1 per cent or less of sodium chlorid. 

 The anion bears an important relation to the toxic effects of salts as illustrated 

 in the results above discussed, a fact which has not received very much con- 

 sideration in the past. The salt effects noted should, like results obtained on 

 ammonification in work above cited, have an important bearing on the practical 

 reclamation of alkali lands. The nitrifying bacteria are affected similarly 

 to the higher plant by the alkali salts and quite differently from the ammonify- 

 ing bacteria." 



Maintenance of soil fertility: Plans and summary tables (Ohio 8ta. Circ. 

 120, pp. 95-115, flgs. 5). — This is one of the annual statements on the subject 

 (E. S. R., 2G, p. 423), bringing the data for the experiments up to the end of 

 1911 and summarizing the results for IS years (1894-1911). 



Reaction changes in the soil by growth of plants and fertilizing, J. G. 

 Maschhaupt (Verslag. Landhouick. Onderzock. Rijkslandbouwproefstat. [Neth- 

 erlandsl, 1911, No. 10, pp. 50-93, pis. 4; abs. m Chem. Abs., 6 (1912), No. 11, 

 p. l/i87). — Previous investigations on the subject are reviewed, and studies of 

 the effect of the growth of plants on the reaction of solutions of ammonium, 

 potassium, sodium, calcium, and magnesium nitrates, sulphates, and chlorids 

 are reported. 



The tests were made (1) by growing the plants in soil in flowerpots with 

 perforated bottoms, the roots being allowed to dip into breakers which contained, 

 alternately, pure solutions, and sand saturated with solutions of the salts 

 named; and (2) by growing the seedlings in the solutions of the salts. It is 

 stated that the first method was well adapted for the purpose of these experi- 

 ments and that it has a decided advantage in that the plants are grown in the 

 natural soil conditions. Better results were obtained when the roots of the seed- 

 lings were first developed to some extent in a culture solution before transfer- 

 ring to the solutions of pure salts. It was thought that a study of the effect of 

 plant growth on the reaction of the solutions would indicate the conditions 

 which may arise in the soil from continued application of a fertilizer containing 

 a predominance of any one salt. 



The results of the studies show that sodium nitrate was physiologically 

 alkaline. In one case, using rye, an alkalinity of 0.006-normal was obtained. 

 The alkalinity was substantially increased in sand culture, 0.02S-normal being 

 obtained with corn. Ammonium sulphate was physiologically acid, the highest 

 degree of acidity being 0.015-normal obtained with corn in snnd culture. Am- 

 monium nitrate was physiologically acid but less so than the sulphate. This 

 result is stated to agree with the work of D. N. Prianishnikov (E. S. R., 17, 



