422 EXPERIMENT STATION RECORD. [Vol.41 



aeration was varied, insufficient aeration retarded the initial accumulation, but 

 after nitrification became active in all samples the accumulation was inversely 

 proportional to aeration." 



Capillary moisture-holding' capacity, W. Gardner {Soil ScL, 7 {1919), No. ^, 

 pp. 319-324, fig. !)■ — The author reviews and analyzes the work of others bear- 

 ing on the subject, and is of the opinion that the dynamic character of typical 

 soil moisture phenomena can not be overlooked in the attempt to define such a 

 constant as moisture capacity. "In order to make postitive progress from a 

 scientific aS well as practical point of view, it would seem, that fundamental 

 concepts of this character should be carefully considered." A laboratory study 

 of the dynamic phases of soil moisture is in progress at the Utah Experiment 

 Station. 



On the penetration of the periodic temperature waves into a substance hav- 

 ing no uniform constitution especially into the soil, K. Aichi {T6ky6 Siig. 

 But. Kizi [Proc. Tokyo Math. Phys. Soc], 2. ser., 9 {1918), No. 22, pp. 527-541).— 

 This is an intricate mathematical analysis of the subject, made in conjunction 

 with actual temperature measurements in Japanese soils and in snow. It is 

 shown that elaborate calculations, for example, by the use of the method of 

 least squares, do not give sufficiently accurate information on which to base 

 discussion of underground temperatures as compared with actual observations. 



The effect of certain colloidal substances on the growth of wheat seedlings, 

 D. S, Jennings {Soil ScL, 7 {1919), No. 3, pp. 20i-2i5).— Experiments at the 

 Utah Experiment Station with a complete nutrient solution, agar, silica, sand, 

 ferric hydroxid, and aluminum hydroxid cultures with wheat are reported. 

 The purpose was to determine whether or not the change in concentration due 

 to solid adsorbing surfaces is sufficient to modify the production of dry matter 

 in a plant. 



It was found that " the effect of adding agar to nutrient solutions was to 

 increase the growth of wheat seedlings in low concentrations and to decrease 

 the growth in higher concentrations of nutrient salts. The introduction of 

 colloidal silica into nutrient solutions resulted in increased weight of wheat 

 seedlings. The increase was apparently due to direct absorption of silica by 

 the plant and not to a change in the effective concentration of the nutrient 

 solution. Silica gel is, therefore, considered unsuited for studies of the charac- 

 ter described in this paper. The introduction of quartz sand, ferric hydroxid, 

 and aluminum hydroxid into nutrient solutions resulted in decreased growth of 

 wheat seedlings. It appears that these substances by their absorptive prop- 

 erties reduce the effective concentration of the nutrient solution." 



The influence of kind of soil and fertilization on nitrogen and ash content 

 of crops, J. G. Maschhaupt {Verslag. Laiulbouirk. Onderzoek. Rijkslandbouw- 

 proefstat. [Nethet-lands'i, No. 22 {1918), pp. 25-llJh fid- !)• — Continuing experi- 

 ments previously noted (B. S. R., 28, p. 520), plat experiments with heather, 

 moor, swamp, loam, and clay soils to determine the effect of the kind of soil 

 and the fertilizers sodium nitrate, pota.ssium nitrate, and ammonium sulphate 

 on the contents of nitrogen and ash in barley, rye, beets, oats, and potatoes are 

 reported. 



A smaller increase in crops was obtained with potassium nitrate than with 

 sodium nitrate on these soils. The influence of the kind of soil was greater 

 with straw and beet and potato leaves than with grain or roots, and was 

 greatest in the silica content of straw. The average silica content of straw 

 from clay soils was five times that of straw from heather soils. There was no 

 comparative effect on the content of bases. The composition of beet and 

 potato leaves was more strongly affected by the kind of soil than was the 



