816 EXPERIMENT STATION RECOED. [Vol. 35 



conditions, increasing the humus content to an extent comparable with alfalfa, 

 manure, and straw. Of the pentosans present, 75 to 80 per cent was decom- 

 posed in all the materials." 



The solvent action of ammonium salts on phosphorites in sand cultures, 

 F. V. Chirikov (T. Tschikikuw) (Iz Rezul't. Veget. Opytov. Lab. Rabot {Rec. 

 Trav. Lab. Agron.), 9 (1913), pp. 436-UO). — This is a continuation of the ex- 

 periments with sand cultures conducted in 1912 (E. S. R., 29, p. 624). In 

 addition to calcium carbonate, magnesium carbonate was also used in 1913 to 

 secure neutralization of ammonium salts, both being taken in quantities 

 equivalent to one-half or all of the sulphuric acid in ammonium sulphate. The 

 phosphorite was Russian, containing 25.86 per cent of phosphoric acid. 



The results of the experiments with barley were fully concordant with those 

 obtained the previous year. No decrease in the yield resulted from neutraliza- 

 tion of the acid with calcium carbonate, but the yield declined when magnesium 

 carbonate was used in place of calcium carbonate. In the experiments with 

 buckwheat the yields were lower when calcium nitrate was replaced by am- 

 monium sulphate. 



Relation of calcium carbonate to the soil phosphates and acid phosphate, 

 J. L. BuEGESS {Bui. N. C. Dept. Agr., 37 {1916), No. 5, pp. 16).— This is a brief 

 popular discussion of the subject based largely on work at the different state 

 experiment stations. 



The influence of lime on the yield and nitrogen content of corn, A. W. 

 Blaib and H. C. McLean {Soil Sci., 1 {1916), No. 5, pp. 489-504, figs. 3).— In ex- 

 periments at the New Jersey Experiment Station on a medium loam soil with a 

 series of 20 twentieth-acre plats arranged for a study of nitrogen availability, 

 an application of ground limestone at the rate of 2 tons per acre increased the 

 yield of shelled corn by about 10 bu. and of stover by 432 lbs. per acre, as com- 

 pared with the yield from a similar series of unlimed plants. 



" The influence of the lime on the yield from the plat which annually re- 

 ceived its nitrogen in the form of ammonium sulphate, as compared with the 

 yield from the similarly treated plat, unlimed, was especially marked. The 

 liming likewise resulted in greatly increased yields on certain of the plats which 

 received their nitrogen in the form of rather slowly available organic materials, 

 as, for example, wheat or rye straw. It also resulted in decided increases in 

 the yields on plats which received minerals only, indicating that in the soil 

 of these plats there was a considerable store of inert nitrogenous material 

 which required only a favorable soil reaction to make it available. Unlimed 

 plats which received an extra heavy application of manure, or manure and 

 nitrate of soda, gave yields fairly approaching or even surpassing the yields 

 given by plats which received similar nitrogenous treatment and lime. That is, 

 the manure or the basic materials in the manure and nitrate of soda apparently 

 decreased the need for lime. The average percentage of nitrogen in the grain 

 and stover from the limed plats was slightly greater than the average in the 

 grain and stover from the unlimed plats. The average recovery of nitrogen from 

 the limed plats was 36.2 per cent and the average from the unlimed plats was 

 25 per cent." 



A list of 18 references to literature bearing on the subject is appended. 



Effect on plant growth of sodium salts in the soil, F. B. Headley, E. W. 

 CuETis, and C. S. Scofield (C7. S. Dept. Agr., Jour. Agr. Research, 6 {1916), No. 

 22, pp. 857-869, figs. 8). — Pot experiments with wheat on sandy loam, loam, and 

 beach sand to determine the influence of the carbonate, bicarbonate, chlorid, 

 and sulphate of sodium when added in amounts varying from nothing to suffi- 

 cient to prevent plant growth entirely are reported. 



