22 EXPEEIMENT STATION RECORD. 



Clod analysis, a means of determining soil structure, IT. Puchner (Mitt. 

 Dcut. Landiv. GcscU., 26 (1911), No. J/, pp. 38-.'i0). — The author describes a 

 method of clod analysis which he has used with satisfactory results in deter- 

 mining the structure of cultivated soils and in studying the thoroughness of 

 cultivation with different forms of tillage implements. 



By means of sieves the soil samples are separated into crumbs (Kriimel) 

 less than 20 mm. in diameter, fine clods (Brockeu) 20 to 40 mm. in diameter, 

 and clods (Klumpen) over 40 mm. in diameter. Examinations of a number of 

 samples of cultivated and uucultivated soils taken at different depths from the 

 surface down to 400 mm. are reported. 



The formation and properties of humus substances, P. Eheenberg (Ghem. 

 Ztg., 3Jf (1910), No. 130, pp. 1157, ll')8; abs. in Chcm. Zcntbl., 1910, II, No. 2//, 

 p. mS; Chem. A6s., 5 (1911), No. 6, pp. 11^7, llJiS).— This article briefly sum- 

 marizes the work of the author and other investigators on different kinds of 

 humus and humus-like substances derived from different sources by various 

 natural and artificial processes. 



The author calls attention to the fact that while comparatively little is known 

 of the actual composition of such substances, apparently two classes of com- 

 pounds are produced in the process of humus formation, (1) those derived from 

 carbohydrates and having an acid reaction, and (2) those derived from benzol 

 derivatives and having an alkaline reaction. The importance of further inves- 

 tigations on the composition and properties of humus is emphasized. 



The question of the study of humus substances, C. Blacher (Chem. Ztg., 

 84 (1910), No. 148, pp. 1314, 1315). — Observations on the behavior of humus 

 compounds in boiler water are recorded. 



On the escape of ammonia from manure during and after hauling to the 

 field, P. LiECHTi and E. Ritter (Landw. Jahrh. Schiceiz, 24 (1910), No. 7, pp. 

 ^81-525, pi. 1, figs. 3). — The authors report investigations from which they con- 

 clude that the loss of ammonia during the hauling of manure is so small that it 

 may be entirely disregarded, but that the loss under the usual methods of 

 applying manure to the soil is considerable. A special piece of apparatus was 

 designed and used to determine the ammonia given off into the air under dif- 

 ferent methods of application of manure. 



The losses of ammonia were found to be especially large when the manure 

 was applied on snow, amounting in the course of a few days to one-third or more 

 of that in the manure, and this is considered less than would actually occur 

 under ordinary methods of manuring. The loss was determined to a large 

 extent by the temperature. With temperatures above 0° C. the loss on snow- 

 covered soil was very small. At temperatures below 0° the losses were greater. 



The importance of peat for the manufacture of nitrogenous fertilizers, 

 R. Schorr (Jour. Amer. Peat Soc., 3 (1911), No. 3-4, pp. 226^232) .—Data are 

 presented to show that the present sources of nitrogenous fertilizers are inade- 

 quate, and the advisability of investigating the possibility of using peat for this 

 purpose is suggested. The efficiency of various processes which have been pro- 

 posed for the manufacture of nitrogenous compounds from peat is briefly dis- 

 cussed. 



Problems in peat filler production, J. N. Hoff (Jour. Amer. Peat Soc, 3 

 (1911), No. 3-4, pp. 192-201). — It is stated that there are at the present time 

 four or five plants producing peat filler in the United States in commercial 

 quantities, the total outimt being perhaps from 15,000 to 20,000 tons per year. 

 The methods used are described. The author is of the opinion that peat makes 

 an ideal filler, although objection has been raised to it on account of the low 

 availability of the nitrogen as compared with that of blood, tankage, or am- 

 monium salts, 



