No. 2, March, 1921] SOIL SCIENCE 207 



which approximates the results obtained by use of the hydrogen electrode. The Hopkins 

 and hydrogen electrode methods show the highest percentage consistency for measuring the 

 reduction of acidity for limed soils. — Heiiry Schmitz. 



INFLUENCE OF BIOLOGICAL AGENTS 



1402. Ames, J. W. Supply of nitrogen in the soil. Ohio Agric. Exp. Sta. Monthly Bull. 

 6": 174-178. 3 tables. — Information concerning changes of the nitrogen supply of the soil 

 occasioned by differences in treatment, under cultivation, with fertilizers, lime and manure, 

 is gained bj' a comparison of the nitrogen content of fertility plots on the Wooster farm. — 

 R. C. Thomas. 



1403. Ellett, W. B., and W. G. Harris. Cooperative experiments for the composting of 

 phosphate rock and sulfur. Soil Sci. 10 : 315-325. 1920. — Using composts of soil and rock phos- 

 phate; soil, rock phosphate and sulfur; soil, rock phosphate, sulfur and manure, inoculated 

 and uninoculated with sulfofying microorganisms, the water soluble, ammonium-citrate- 

 soluble and total phosphoric acid as well as the sulfuric acid, total nitrogen, nitrate and 

 ammonia were determined. The results show that the addition of manure to a compost of 

 soil, sulfur and rock phosphate increases the availability of the rock phosphate. All Virginia 

 soils have some sulfofying power. The composting of sulfur, soil, rock phosphate, and 

 manure is not recommended for the use of farmers because of the slowness of the process and 

 mechanical difficulties. — W. J. Robbins. 



1404. LiPMAN, J. G., AND J. S. JoFFE. The influence of initial reactions on the oxidation 

 of sulfur and the formation of available phosphates. Soil Sci. 10: 327-332. 2 fig. 1920.— 

 Varj'ing quantities of sulfuric acid were added to soil containing 15 per cent rock phosphate 

 and 5 per cent sulfur. The hydrogen-ion exponent of the soils varied from Ph. 4.7-5.4. The 

 soluble phosphates and hydrogen-ion concentrations were determined weekly. By the end of 

 the 12th week the hydrogen-ion exponent had fallen to Ph. 1.4-2.0 but little further change 

 occurred. The amount of soluble phosphate increased during the 20 weeks of the experi- 

 ment reaching 83 to 85 per cent but no influence of the initial reaction on the formation of 

 the soluble phosphates was noted. — W. J. Robbins. 



1405. Maze, P., Vila et Lemoigne. Transformation de la cyanamide en uree par les 

 microbes du sol. [Transformation of cyanamide into urea by micro-organisms of the soil.) 

 Compt. Rend. Acad. Sci. Paris 169: 921-923. 1919.— See Bot. Absts. 7, Entry 1334. 



1406. Whiting, A. L., .\nd Roy Hansen. Cross-inoculation studies with the nodule 

 bacteria of lima beans, navy beans, cowpeas and others of the cowpea group. Soil Sci. 10: 

 291-300. 1920. — Pot experiments with leguminous plants and pure cultures of B. radicicola 

 show that the nodule bacteria of the lima bean {Phaseolus lunalus) are distinct from those of 

 the navy and kidney bean {Phaseolus vulgaris) but are identical with those of the cowpea. 

 (Vigna sinejisis). — W. J. Robbins. 



1407. Wright, R. C. Nitrogen economy in the soil as influenced by various crops grown 

 under control conditions. Soil Sci. 10: 249-289. 9 fig. 1920.— Leguminous and non-legumi- 

 nous crops were grown in containers holding about 100 lbs. of soil. Nitrogen in the plant 

 and in the soil was determined. Under the conditions of the experiment the fallow soil 

 showed a loss of nitrogen. Under some crops there was an absolute loss of nitrogen in excess 

 of that recovered in the crop and this varied with the crop and soil. Legumes may show 

 this loss as well as non-legumes. When nitrogen fixation takes place in the growth of 

 legumes the removal of the crop above ground depletes the soil of nitrogen just as if a non- 

 leguminous crop had been grown. — W. J. Robbins. 



