774 Summary of Agricultural Experiments, [dec, 



of particles between 02 and o'4 millimetre in diameter, " silt " as 

 particles between 0 04 and 001 millimetre, and so on.) The authors 

 go on to point out that such analyses alone do not provide sufficient 

 criteria of the economic value of soils ; they must be considered in the 

 light of such important factors as the amount of organic matter and 

 calcium carbonate present in the soil, and, above all, the condition of 

 the soil in regard to water supply and retention of moisture must be 

 taken into consideration. Climatic conditions, and, finally, the 

 chemical analysis, also influence the interpretation of the results. 



The point of most interest to the practical agriculturist in this paper 

 is the minor position given to purely chemical considerations. In a 

 review of an article by one of the authors in last month's Journal 

 (p. 653) mention was made of the views of the Bureau of Soils, U.S.A., 

 in regard to this question, and it was pointed out that still less con- 

 sideration is given in America to the chemical analysis of soils. In the 

 present paper the main defects of chemical analysis are stated to be 

 that "it does not aim at finding out the actual composition of the 

 soil ... it does not deal with the whole of the soil, but only with 

 the less resistant portions . . . the methods are arbitrary." On the 

 other hand, the advantages of mechanical analysis are that it "gives 

 a complete picture ... it accounts for many of the peculiarities ob- 

 served in cultivation." Its disadvantages are that it is restricted in its 

 application, inasmuch as it cannot be used for chalk and peat soils 

 (such as the fen soils), being most useful for mineral soils, i.e., the 

 sands, loams, and clays which form the greater portion of the agri- 

 cultural soils of this country. 



Formation of Calcium Carbonate in the Soil (Jour, of Agric. Science, 

 Vol. IV., No. 2, October, 191 1). — In this paper Mr. C. T. Gimingham 

 gives an account of his investigations on the formation of calcium 

 carbonate in the soil by bacteria. A supply of this substance is indis- 

 pensable for the maintenance of fertility, and as it is constantly being 

 removed by various processes connected with the nutrition of plants, 

 it is necessary to explain why many soils maintain their fertility 

 though chalk or lime has not been artificially supplied. The author 

 has succeeded in isolating a number of bacteria which have the power 

 of manufacturing carbonate of lime from a common constituent of 

 plant tissues, namely, oxalate of lime, a salt which in its chemical 

 constitution is not far removed from carbonate of lime. 



Manuring of Meadow Land (Field Expts. in Staffordshire and 

 Shropshire, and at the Harper Adams Agric. Coll., Kept., 19 10). — 

 These experiments were started in 1903 in conformity with a scheme 

 of the Agricultural Education Association, and the results for eight 

 years are given in this report. 



The field was laid down many years ago, the soil being a stiff 

 clay loam resting upon a bed of clay overlying the red sandstone. A 

 dressing of if cwt. nitrate of soda, 2.\ cwt. superphosphate, and \ cwt. 

 sulphate of potash per acre gave in eight years a yield of 15 tons 11 cwt. 

 of hay per acre, or 6 tons 7! cwt. of hay more than the unmanured 

 plot; valuing the hay at 505. per ton makes the profit due to the use 

 of this dressing in eight years £6 19s. The effect of omitting sulphate 

 of potash was slightly to reduce the yield and the profit, while when 

 superphosphate was left out a loss resulted compared with the un- 



