19161 SOILS — FERTILIZERS. 517 



It was found that artificial fertilization with potash and phosphoric acid in 

 geuei-iil improved the quality and increased the yield of the crop. When nitro- 

 gen fertilization was also employed, especially on grass, the yield was further 

 increased. Nitrogen fertilization improved grain crops, but continued fertiliza- 

 tion with potash and phosphoric acid alone generally became gradually in- 

 jurious. On poorly drained soils fertilization had little effect. 



Fertilizer ratio experiments with grass on Hagerstown loam, C. F. Noll, 

 O. ScHREiNER, and J. J. Skinneb (Pennsylvania Sta. lipt. 1914, pp. 22-36, pis. 

 2). — Field experiments in which acid phosphate, sodium nitrate, and potassium 

 chlorid were applied to silt loam soil for four yeai-s in 6G different fertilizer 

 ratios of phosphate, nitrate, and potash graded in 10 per cent stages are re- 

 ported. " The total amount applied on each plat totaled 50 lbs. per acre of the 

 fertilizer elements, PzOs, NHs, and K2O alone or in combinations of two or 

 throe of these. The plats were located in a permanent pasture field where the 

 composition of the pasture was chiefly Canada blue grass, Kentucky blue grass, 

 and timothy with a very little white clover and red clover." 



The various phases of the results obtained are presented by means of the 

 triangular diagram employed by the Bureau of Soils of the U. S. Department 

 of Agriculture in solution culture experiments in studies of organic soil con- 

 stituents (E. S. R., 24, p. 32; 26, p. 224). 



ic was found that " used alone, nitrate has given a large increase over the 

 untreated plats in yield of hay, while both phosphate and potash have yielded 

 a little less than the checks. With increase in percentage of NHj applied as 

 nitrate, the yields have increased, and with increase in percentage of either P2OB 

 or K2O the yields have not increased. The plats [receiving] 50 per cent or more 

 of NHa as nitrate have considerably exceeded in yield those in the subtriangles 

 which have received 50 per cent or more of P2O5 or K2O. There has been a 

 slightly greater response from K2O than from PiOs. The slight differences in 

 the texture of the soil on the different plats have had little influence on the 

 yields. The depth of surface soil has had a marked influence upon the yield." 



Legumes as green manure, W. T. McGeokge {Hawaii Sta. Rpt. 1915, pp. S2, 

 33). — Pot experiments made by A. R. Thompson with a calcareous soil and 

 a soil poor in lime in which 32 varieties of legumes were grown are reported. 

 At maturity the duplicate plants in two pots were removed, weighed, and the 

 nitrogen content determined. Two pots were left of each variety of legume 

 planted, the plants being turned under to decompose. 



" In all instances the [content of] nitrates in the soil from which the legumes 

 had been removed was much lower than in the check soil, but these soils low 

 in nitrates on standing in the open air soon equaled in nitrate value the soil 

 of the check pots. Where much legume material was turned under the nitrates 

 in the soils were greatly increased. The plants grown in soils deficient in 

 lime made a poor growth and had a lower nitrogen content, calculated on a 

 water-free basis, than the plants grown in soils rich in lime. In a second 

 experiment lime was added to the lime-poor soil, but the plants grown in this 

 soil were also undersized and low in nitrogen." 



Legume inoculation and nitrogen fertilization on upland moor meadows 

 and pastures, B. Tacke (Mitt. Yer. Ford. Moorkultur Deut. Reiche, 54 (1916), 

 No. 3, pp. 37-47). — Experiments on the possibility and practicability of substi- 

 tuting nitrogen fertilization for inoculation of soil by nodule bacteria for 

 leguminous pasture and meadow crops are reported. 



The results are taken to indicate that nitrogen fertilization can replace 

 inoculation only where more or less active nodule bacteria are present in the 

 soil in sufficient numbers and distribution. The substitution of nitrogen 



