gl8 EXPERIMENT STATION RECORD. 



loams had a larger proportion (30 per cent) of their total phosphorus avail- 

 able than did silts and clays. The noncalcareous sands and sandy loams con- 

 tained approximately the same amount of available phosphorus as the calcare- 

 ous silts and clays. The calcareous black clay loams contained more available 

 phosphorus than any of the other classes of soils, except the calcareous sands 

 and sandy loams. The noncalcareous silts and silt loams and acid clays and 

 clay loams were deficient in available phosphorus. 



The analytical methods employed are outlined. 



The red clay soil of Porto Rico, P. L. Gile and C. X. Ageton (Porto Rico 

 Sta. Bui. U (19 W, pp. 24, pi. 1). — ^This bulletin reports chemical studies and 

 fertilizer experiments with the red clay soil, which is one of the most exten- 

 sive soil types of Porto Rico. The soil is a fairly heavy clay underlain by an 

 Impervious subsoil, and requires good cultivation and drainage to be productive. 

 It Is characterized chemically by a high content of iron and aluminum, moderate 

 amounts of nitrogen, phosphoric acid, and potash, and no carbonates. It is 

 almost uniformly acid and frequently low in organic matter. 



The soil is used chiefly for the production of coffee and sugar cane, and 

 where it has been for a long time continuously in cane certain areas have 

 become sick or tired and do not respond to fertilizers or superficial disinfection. 



Fertilizer experiments carried on with sugar cane showed, however, that the 

 normal soil is benefited by liming and fertilizers, and that nitrogen is the 

 constituent most needed and probably increases the yield as much as a com- 

 plete fertilizer. The cause of the unproductiveness of the sick soils was not 

 determined. 



Soils, G. AucHiNLECK (Imp. Dept. Agr. West Indies, Rpt. Agr. Dept. Grenada, 

 1912-13, pp. 11-14). — Physical analyses and data obtained by determinations 

 of shrinkage and friability (E. S. R., 27, p. 120) of red, black, and gray soils 

 originating from the weathering of lava and from the deposition of volcanic 

 ash, mud, sand, or gravel are reported. The red soils are heavier than the black 

 and the water content when air-dried is higher. " The gray soil is lightest of 

 all, probably containing a larger amount of unweathered fragments." 



Studies of meteoric waters, soil, and air at the observation stations 

 of the Charcot expedition, A. Muntz and E. Lain6 (Ann. Inst. Nat. Agron., 

 2. ser., 12 (1913), No. 2, pp. 179-231, figs. 7).— The results reported in part 1 

 of this article, relating to nitrates and ammonia in meteoric waters, have 

 already been noted from another source (E. S. R., 26, p. 515). The second 

 part relates to unsuccessful attempts to isolate active nitrifying organisms from 

 samples of debris collected from icebergs, it being impossible to obtain samples 

 of true soil in the antarctic regions in which these observations were made. 

 The third part reports examinations showing that the carbon dioxid content 

 of the air of the antarctic region is decidedly smaller than that of temperate 

 or tropical regions, the average found being about 2 parts per 10,000 parts of 

 air. The oxygen content was found to be about the same as that of other 

 regions. 



The nitrifying: efficiency of certain Colorado soils, W. G. Sackett (Colo- 

 rado 8ta. Bui. 193 (1914), pp. 3-43, figs. 3). — Continuing his investigations into 

 the causes of the excessive accumulation of nitrates in Colorado soils (E. S. 

 R., 28, p. 31), the author made a detailed study of the nitrifying eflaciency of 

 these so-called " niter " soils as well as of soils from various places outside of 

 the State. The term " nitrifying efficiency " is used in this connection " to 

 denote not only the presence of the nitrifying organisms in the soil which are 

 capable of exercising their specific function under favorable conditions (nitrify- 

 ing power) but also the suitability of the soil as a medium in which the process 

 of nitrification may proceed advantageously (nitrifying capacity)." 



