19191 SOILS FERTILIZERS. 213 



to produce a favorable environment for the activities of the nitrifying bacteria. 

 Increasing the amount of lime beyond the point necessaiy for neutralization 

 did not retard nitrification, although the final total nitrate content of the soil 

 in many cases was found to be less than where smaller applications of lime 

 were made. This was thought to be due to increased ammonia and nitrate 

 assimilation and nitrate reduction through stimulated microbial activities. Low 

 moor soils of neutral reaction required no liming to stimulate nitrification. 



With respect to the presence of nitrifying organisms in high moor soils, it 

 is stated that where the soil acidity was reduced through the chemical reac- 

 tion of the basic elements of a phosphate fertilizer, nitrate formers were com- 

 pletely lacking. Applications of lime made at the rate of 1,000 kg. of calcium 

 oxid per hectare (about 890 lbs. per acre) failed to stimulate the development 

 of nitrifying organisms except in the immediate vicinity of tlie lime particles. 

 An application of 2,000 kg. resulted in a further increase in nitritiers, attributed 

 to an increase in the number of spots rich in lime. The nitrifying activities of 

 a moor soil thus treated are said to have been considerably less than in a nor- 

 mal mineral soil. 



Nitrog-en contents of cacao soils planted with, and without bois immortel 

 shade, J, de Verteuil (Bui. Dept. Agr. Trinidad and Tobago, 18 (1919), No. 1, 

 pp. 6S). — Deternunations of the total nitrogen and of nitrate nitrogen in cacao 

 soils shaded with Ei-ythrina and in similar soils without shade were made at 

 quarterly intervals during 1918 to ascertain whether the immortel was bene- 

 ficial to the cacao in producing a larger supply of nitrogen in tlie soil. 



The shaded soils showed a range in total nitrogen of from 0.078 per cent in 

 June to 0.129 per cent in December, and in nitrates from O.0O0G2 per cent in 

 September to 0.00093 per cent in March. In the unshaded soil the total nitro- 

 gen ranged from 0.091 per cent in September to 0.115 per cent in December, 

 and the nitrates from 0.00042 per cent in September to 0.00077 per cent in 

 December. 



The organic phosphorus of soil, R. S. Potter and R. S. Snyder (Soil 8ci., 

 6 (1918), No. 4, pp. 321-332, figs. 2). — This paper, a contribution from the Iowa 

 Experiment Station, describes further investigational work planned to de- 

 termine whether the method proposed by Potter and Benton (E. S. R., 36, p 

 212) actually differentiates between the organic and inorganic phosphorus in 

 the soil, this point having been questioned by Gortner and Shaw (E. S. R., 37, 

 p. 121 ) , together with observations on the nature of certain organic phosphorus 

 compounds. 



An examination of a subsoil taken 3 ft. below the surface and containing no 

 organic matter but a considerable amount of colloidal clay failed to show any 

 so-called organic phosphorus, which is held to indicate that the latter was not 

 confused with colloidal clay in applying the method under observation. The 

 addition of phytin to the soil did not I'esult in its extraction to any appreciable 

 extent with a 1 per cent hydrochloric acid solution. 



Hydrolysis curves for phytin and nucleic acid were determined, hydrolysis 

 being effected with 5 per cent sulphuric acid at 100° O. The curve for phytin 

 was found to be a straight line and after two hours that for nucleic acid ap- 

 proximated a straight line, showing both reactions to be of the first order. 

 Curves for the hydrolysis of the organic phosphorus of Carrington silt loam 

 and two samples of Miami silt loam soil were also ascertained. The results aro, 

 deemed to be rather inconclusive, except that nucleic acid was evidently absent 

 except in the Carrington silt loam and then was present only to a slight extent. 

 The directions of the curves are said to have been such that the organic phos- 

 phorus may have been due to phytin or to a pyrmidin nucleotid. 



A list of references comprising 16 titles is appended. 



