SOILS FEETILIZERS. 133 



Gypsum decreased the calcium carbonate content of the soil, but increased the 

 total calcium oxid content. The highest occurrence of inorganic carbon dioxid 

 was due to ground limestone, burnt lime with manure being second, and burnt 

 lime alone third. In general the carbon dioxid content decreased with the 

 depth, as did also the lime content. Approximately 36.8 per cent of the lime 

 applied with manure, 39.7 per cent of the burnt lime applied, and 40.3 per cent of 

 calcium oxid of the limestone treatment were found to exist as carbonates. 

 Approximately 24.3 per cent, 15.9 per cent, and 22.5 per cent of the calcium 

 oxid applied to three different plats occurred in forms other than carbonates. 



The magnesium percentage decreased in every instance, the loss being 

 greatest in the first 7 in. and least in the la.st 7 in. Every case of lime treat- 

 ment resulted in a decreased total potash content. No correlation between 

 residual lime and residual potash was found. Phosphorus was conserved where 

 lime was applied as burnt lime, both with and without manure. The effect of 

 ground limestone was not so marked upon the phosphorus conservation as was 

 that of burnt lime, while a loss occurred in the plats treated with gj'psum. 



Field experiments with, lime, F. D. Gardnee (Pennsylvania Sta. Rpt. 1913, 

 pp. 22-38). — Field experiments extending over many years with wheat, oats, 

 corn, clover, and timothy on silty clay loam and residual limestone soils of the 

 Hagerstown series to determine the best form of lime to apply, and in part noted 

 above, are reported in detail. The results indicate that finely pulverized raw 

 limestone is somewhat superior to burned or caustic lime when used in equiva- 

 lent amounts on these soils. 



Experim.ents to determine the influence of the fineness of subdivision and 

 richness in magnesium carbonate of crushed limestone used for amendment 

 of acid soils, "W. Thomas and W. Feeae {Pennsylvania Sta. Rpt. 1913, pp. 206- 

 219, pis. 8). — Basket experiments with red clover on an acid silty loam soil to 

 determine the influence of the degree of fineness of crushed limestone when 

 used for the correction of acidity are reported. The limestone used was of five 

 degrees of fineness, these being the sizes passing No. 20, 40, 60, 80, and 100 

 sieves. A sufficient quantity was added to the soil to neutralize its acidity. It 

 is conchided from these experiments that " on silty loams and on soils of 

 heavier texture, on lands where soil acidity is the chief factor limiting clover 

 production, crushed limestone used for amendment should be at least 00-mesh 

 in fineness of pulverization." 



Further experiments on the same soil to determine the effect of the mag- 

 nesium carbonate content of dolomite upon the growth of clover are also re- 

 ported. Dolomite and calcium and magnesium hydroxids prepared from the 

 carbonates were used. It was found that germination in all the pots that re- 

 ceived magnesium mixtures and in those that received dolomite was slower by 

 three to four days than where pure limestone was used, but the final average 

 yields were nearly identical. It is concluded that " in this experiment the pres- 

 ence of magnesia in the amendment did no injury except, that indicated by a 

 slight delay in germination, a temporary abnormal coloration of the leaves, and 

 a somewhat diminished root development." 



The lime resources of Pennsylvania, W. Frear and E. S. Eeb (Pennsylvania 

 Sta. Rpt. 1912, pp. 272-UO, pis. 3, fig. i).— This report covers in considerably 

 more detail practically the same ground covered in a previous report (E. S. R., 

 30, p. 822). 



Commercial fertilizers, P. L. Hibbard (California Sta. Bui. 259 (1915), pp. 

 51-104)- — This bulletin contains actual and guarantied analyses of 505 .samples 

 of fertilizers and fertilizing materials obtained from farmers, purchasers, and 

 agents in California during the year ended June 30, 1915. In 90 samples there 



