1919] SOILS — FERTILIZERS. 19 



Gypsum applied at the rate of from 300 to 400 lbs. per acre before fall plowing 

 is deemed worthy of trial as a mineral flocculent, while burned lime is regarded 

 as of value for small areas. 



The value of legumes on Indiana soils, A. T. Wiancko, S. D. Conner, and 

 S. C. Jones (Indiana Sta. Bui. 226 (1919), pp. 19, figs. 6). — Based on results 

 secured on the station farm and on outlying exjieriment fields, it is concluded 

 that from 25 to 50 per cent of the nitrogen and humus of the soil of the State 

 has been used up or lost by the cropping systems employed, and that the in- 

 creased growth of legumes is the easiest and most economical method of re- 

 storing nitrogen and organic matter to run-down soils. As an average for 61 

 crops grown on 8 experiment fields during the last 12 years, crop rotations con- 

 taining legumes produced 4.6 bu. of corn and 4.7 bu. of wheat per acre more than 

 rotations in which no legumes were grown. Factors contributing to successful 

 clover production are indicated and the use of soy beans or cowpeas recom- 

 mended when clover fails. 



The continuous growing of wheat and rye with and without a legume as 

 green manure, 1917, J. G. Lipman and A. W. Blair (New Jersey Stas. Rpt. 

 1917, pp. 350-352). — In the continuation of work previously noted (E. S. R., 

 39, p. 725), further observations have been made upon the effect upon the 

 nitrogen supply of the soil of growing a legume between the main crops of a 

 rotation. 



Wheat and rye grown alone have produced at the rate of 7.33 and 13.67 bu. 

 of grain and 780 and 1,720 lbs. of straw per acre, containing 14.44 and 24.94 

 lbs. of nitrogen, respectively. Wheat followed by soy beans as a green manure 

 crop produced 12.33 bu. of grain and 1,420 lbs. of straw, containing 28.78 lbs. 

 total nitrogen. Under similar conditions rye produced 14.33 bu. of grain and 

 2,760 lbs. of straw, containing 34.7 lbs. total nitrogen. 



H-ion concentrations in extracts of peat soils and of peat- and humus- 

 forming plants, H. Kappen and M. Zapfe (ZentM. Agr. Chcm., Jfl (1918), No. 7, 

 pp. 193-197; abs. in Physiol. Abs., 3 (1919), No. 11, p. 583; Chem. Abs., 12 

 (1918), No. 19, p. 20^5).— Continuing work previously noted (E. S. R., 37, p, 

 623), observations are described on samples of soils taken at different depths 

 ranging from to 165 cm. (about 64.4 in.), of the subsoil below 165 cm., and 

 of cultivated peat soil receiving different fertilizer treatments, together with 

 samples of fresh sphagnum, and pine and spruce needles. Extracts were pre- 

 pared by treating 10 gm. of the material for 2 hours with 200 cc. of either water, 

 normal potassium chlorid solution, or a 10 per cent calcium acetate solution. 

 The water extracts were slightly yellowish in color, while the other extracts 

 were colorless. The titratable acidity and the H-ion concentration were deter- 

 mined in each case. Observations were also made on the conductivity of the 

 aqueous solutions and the air-dry and the ignited residues determined. 



It is concluded that soluble acids were present in the peat soil in traces only, 

 since the H-ion concentration but slightly exceeded that corresponding to the 

 neutral point. The power of these soils to decompose neutral salts is thought 

 to be due to an exchange of ions rather than to the liberation of free acid. 

 The H-ion concentration of aqueous extracts of peat- and humus-forming plants 

 was generally high and the true acidity marked. 



The value of ammonification test, J. C. Temple (Georgia Sta. Bui. 126 

 (1919), pp. S-18). — Observations on the ammonifying efficiency, ammonifying 

 inoculating power, and ammonifying capacity of different soils subjected to 

 various treatments have led to the conclusion that the ammonification test is 

 of little value in ascertaining the nature of the soil microflora, because (a) 

 the rate of ammonia production is largely controlled by the soil medium, (b) 

 all soils are well supplied with bacteria capable of changing nitrogen into 



