420 EXPERIMENT STATION RECORD. TVoI 37 



with recommendations as to fertility requirements based on field eii)eriment8 

 with the prevailing types. 



" Experiments which have been condncted in this county on the Cecil clay, 

 in Iredell on Cecil clay loam, and in Gaston on Cecil sandy loam have shown 

 for several years that nitrogen and phosphoric acid are the constituents chiefly 

 needed. Potash has not been generally shown to be essential except for such 

 crops as tobacco and potatoes." 



Lime requirements of some acid soils, S. D. Conner {Jour. Asfoc. Off. Agr. 

 Chem., 3 (1917), No. 1, pp. 139, 140). — Studies at the Indiana Experiment Sta- 

 tion of the lime requirements of very acid peat, peat, peaty sand, loam well 

 supplied with organic matter, and silt loam soils, using the Hopkins potassium- 

 nitrate method, the Veitch limewater method, the Hutchiuson-MacLennan cal- 

 cium-bicarbonate method, and the Jones calcium-acetate method, are reported. 



It was found that the Hopkins method gave much lower results than the 

 others, especially on soils containing much organic matter. " This method 

 possibly gives too low an estimate as an average; but ... in most cases it is 

 just as near as any other method to the amounts of lime which have given 

 profitable returns by actual tests on the crops. While the Veitch method doubt- 

 less more accurately determines the amount of lime th;it a soil has the capacity 

 to absorb, ... it is not protitable to add this much lime to soils high in organic 

 matter. The results of these tests indicate that organic acidity is much less 

 toxic in soils than inorganic acidity. The Jones calcium-acetate method gives 

 higlier results than the calcium-bicarbonate method. . . . None of the soil- 

 acidity methods can be use<l as an exact estimate of the most profitable amount 

 of lime to be added to the soil." 



In this connection the opinion is expressed that '* a soil-acidity estimation is 

 probably the most important single test that can be made In the laboratory to 

 determine the chemical requirements of the soil." 



Study of soil containing residual limestone. H. A. Notes {Jour. Assoc. 

 Off. .Af/r. ('hem., 3 (1917), No. 1. pp. i5/-/55).— Studies at the Indiana Experi- 

 ment Station of the acidity of a residual silty clay orchard soil containing about 

 60 per cent of fine silt and 120 per cent of clay and underlaid with limestone 

 rock are reported. Samples were taken representing the following depths: 

 Surface to 9 in.. 9 to 18 in., 18 to 27 in., 27 to 36 in., and 36 to 45 In. Acidity 

 was determined by the Hopkins potassium-nitrate method. 



It was found that the acidity did not decrease with the depth and showed no 

 regular decrease or increase dependent upon the distance from bed rock. The 

 acidity results could not be correlated with either the percentage of nitrogen 

 or the volatile matter in the samples. The presence of limestone fragments in 

 this acid soil leads to the conclusion that coarse screenings would not correct 

 the acidity and that for acid silt and clay soils finely ground limestone is 

 necessary. 



The character of certain soils in the area devastated by the eruptions of 

 the Soufriere of St. Vincent in 1902-3, li. A. Tempany {West Indian Bui., 16 

 {1917), No. 2, pp. 126-137. fig. i).— Physical, chemical, and biological studies 

 of samples from the ash deposits In the Carib country of St. Vincent which were 

 laid down at the time of the eruption of the St. Vincent Soufriere in 1902 are 

 reported. These deposits are said to range in thickness from 14 to 18 in. 



" Physically the soils were found to consist of coarse sandy tyi^es ; they 

 showed shrinkages ranging between 1 and 2 per cent, thereby Indicating the 

 formation of a certain amount of colloidal material. Chemically the soils 

 showed small contents of organic carbon and nitrogen; they were extremely 



