132 EXPEEIMENT STATION EECORD. 



as well as on that of the ammoniacal solution, resulting in the formation of 

 acid-soluble phosphorus compounds. 



As a conclusion to his review the author presents two theses regarding the 

 present status of the organic phosphorus of the soil: (1) A part of the phos- 

 phorus of the soil does not belong to the mineral phosphates; (2) there is a 

 definite relation between the organic matter and the phosphorus of a soil. 



The author believes that the characteristics of these phosphorus compounds 

 of the soil are an important study for the future. The direction of these in- 

 vestigations must be toward an understanding of the properties of humus, the 

 organic colloids, and the organic mineral compounds of the soil. 



Eeport of the physiologist, O. Loew (Porto Rico Sta. Rpt. 1909, pp. 15-18). — 

 This report is devoted to a brief statement of progress in investigations on 

 " sick " or " tired " soils of Porto Rico (E. S. R., 23, p. 422). 



Conservation of the purity of soils in cereal cropping, H. L. Bolley 

 {Science, n. ser., 32 (1910), No. S2.5, pp. 529-5Jfl). — This is an argument in 

 favor of the more general adoption of more careful methods of seed disinfection, 

 soil culture, and rotation of crops to reduce losses from plant diseases. It is 

 stated that it is not necessary, for example, that " wheat yields should fall 

 from the now promising ones of 30 to 60 bu. per acre to the general average of 

 12 to 15," but that this can not be prevented " unless we recognize this 

 question of soil sanitation, or, if you will, the nec-essity of conserving the virgin 

 purity of the laud." 



Soil wastes in the cane field (Queensland Agr. Jour., 25 (1910), No. 3, pp. 

 113-117). — This article discusses the drainage wastes and means of reducing 

 loss from this source, as well as the fertilizer requirements of cane soils. For- 

 mulas for various fertilizer mixtux'es for cane are given, and the best methods 

 of application are discussed. Fractional application and thorough mixing of 

 the fertilizers with the soil to a depth of 3 in. are recommended. 



Experiments with nitrogenous fertilizers, W. Schneidewind et al. (Landw. 

 Jahrh., 39 (1910), Ergunzungsh. 3, pp. 209-236; ahs. in Ghent. Zentbl., 1910, II, 

 No. 6, p. i05; Jour. 8oc. Che-rn. Indus., 29 (1910), No. 17, pp. 1070, 1071).— 

 These experiments included comparative tests of sodium nitrate, potassium 

 nitrate, calcium nitrate, ammonium sulphate, lime nitrogen, organic com- 

 pounds, and green manures, studies of losses of nitrogen with top-dressings of 

 ammonium sulphate and calcium nitrate, and the fixation of ammoniacal 

 nitrogen by the zeolites of the soil. 



The soils used in these experiments were of two kinds, 90 per cent sand 

 plus 10 per cent clay, and 50 per cent sand plus 50 per cent clay. The crops 

 grown in the experiments included oats, rye, and potatoes for the organic 

 fertilizers, and clover, peas, beans, and vetches for the green manures. 



The effect of the sodium nitrate was most pronounced. The general effect 

 of the ammonium sulphate as compared with the sodium nitrate was rated at 

 93 per cent, but as a source of nitrogen at only 89 per cent. "With potatoes 

 the ammonium sulphate was as effective as the sodium nitrate. The calcium 

 nitrate as compared with sodium nitrate was rated at 96 per cent both as to 

 general effectiveness and as a source of nitrogen. Its effect was most pro- 

 nounced with potatoes. The lime nitrogen as compared with the sodium nitrate 

 was rated at 85 per cent in general effectiveness and at 82 per cent as a source 

 of nitrogen ; as compared with ammonium sulphate its general effect was rated 

 at 91 per cent and as a source of nitrogen at 90 per cent. 



The organic fertilizers were much less effective forms of nitrogen. Animal 

 guano was 67 per cent as effective as sodium nitrate, fish meal 73 per cent, 

 meat meal 71 per cent, dried blood 56 per cent, ground horn 55 per cent, and 

 ground leather 15 per cent. 



