124 EXPERIMENT STATION RECORD. 



of the soil at depths of 0.3 and 1 meter with a watei* content of 0.074 gm. per 

 cubic centimeter as a mean of 5 measurements was 0.204 gram-calorie per cubic 

 centimeter, hence the thermal capacity of the soil per unit volume was 0.4. 

 The diurnal variation of the temperature became almost insignificant at a 

 depth of 60 cm. 



The extreme temperatures for each month at the different depths, as well as 

 the constants as analyzed by the Fourier series, are given. At a depth of 5 

 meters the minimum temperature was observed in May, the maximum in 

 November. The analysis by the Fourier series indicates that the soil studied 

 may be taken roughly " as a homogeneous substance, and that the differential 

 equation for linear flow of heat with a constant diffusivity may be applicable 

 for any stratum of the soil at that locality. . . . 



" The amount of the diurnal thermal exchange of the Osaka soil is 42.3 gram- 

 calories per unit area* in average. It is subject to a very great variation in the 

 course of a year, being greatest in May and least in January. The diurnal heat 

 content varies wuth season and weather condition. . . . 



" The thermal conductivity of the Osaka soil diminishes regularly with the 

 depth. . . . 



" There is a marked annual variation in the diffusivity of soil. The maximum 

 occurs in March and the minimum in August in the surface layer ; the maximum 

 takes place in July and the minimum in August in the second layer ; the maxi- 

 mum occurs in July and the minimum in November in the third layer ; and 

 the maximum takes place in February and the minimum in September. This 

 periodic variation of the thermal diffusivity of soil is probably due to the annual 

 variation of the soil temperature and of water contained in pore spaces of the 

 soil." 



The water economy of the soil, Quante {Filliling's Landw. Ztg., 58 {1909), 

 Nos. 16, pp. 592-605; 17, pp. 609-627). — This article reviews investigations bear- 

 ing on the subject and discusses the importance of water in plant growth on 

 different kinds of soil, as well as the influence of cultural methods on the water 

 content of soils. 



Soil moisture in crop production (Mark Lane Express, 102 (1909), No. Jf067, 

 p. 25.i). — This is a note on a paper read by F. H. King at the meeting of the 

 British Association at Winnipeg. The paper discussed water as a plant food 

 and as a carrier of plant food in the soil and plant, as well as the amount of 

 water required to produce a ton of dry matter in different crops. Omitting 

 evaporation, this is stated to amount to 200 to 400 tons. It is estimated that, 

 including evaporation, 3.6 to 4.3 in. of water are required to produce 12 bu. of 

 wheat or 20 bu. of barley. 



Soil acidity, W. P. Kelley (Amer. Pert., 31 (1909), No. -J, pp. 22-24) .—This 

 article discusses briefly the various methods which have been proposed for the 

 determination of soil acidity as well as the origin of the acid condition and 

 practical methods of correcting acidity. 



Effects of salts on soils, C. S. Tayloe (Dept. Agr. Bengal, Quart. Jour., 2 

 (1909), No. J,, pp. 281-287). — This article describes the types of alkali soils 

 occurring in Bengal. These include not only the so-called usar and reh soils, 

 which have been formed by the accumulation of salts resulting from decomposi- 

 tion of the soil constituents in place, but also the nitrate soils and those which 

 have been rendered saline by frequent inundations of brackish water. Atten- 

 tion is directed mainly to the latter class in this article, and it is shown that 

 their sterility is not due entirely to excess of saline substances but partly at least 

 to the fact that they are almost absolutely devoid of bacteria and contain very 

 small amounts of nitrogen. Determinations of the soluble salts in such soils at 

 different depths are reported. 



