516 EXPERIMENT STATION" BECOKD. 



the soil and its humic acid with the kind of organic fertilizer previously applied 

 to the soil, (3) in the soil and its humic acid with similar groups found in pure 

 proteins, and (4) to compare the amounts of amino-acid nitrogen, as such, in 

 the soil with that found by hydrolysis." 



It was found that the amount of nitrogen precipitated from a neutralized 

 alkali extract of soil varied in a qualitative way inversely with the strength of 

 the acid. The amount of liumin nitrogen extracted by dilute alkali from soil 

 was very high when compared with the amounts in proteins. Dilute alkali did 

 not extract any typical class of organic compounds from the soil. The amount 

 of amino acid and peptid nitrogen in soil was found to be very small when 

 compared to the amounts of amino acids formed by hydrolysis. 



Transformation of vegetable compounds into humus, A. Tbusov (Selsk. 

 Klioz. i Liesov., 2^8 (.1915), July, pp. ^09-.'t37). — Experiments are reported in 

 which it was found that the humificatjon of various organic compounds consists 

 of both chemical and biological processes, woody substances being humified by 

 chemical compounds and fungi, albumin by biological processes alone, and 

 substances containing tannin and chlorophyll by chemical proces.ses alone. 

 The process of huniification was aided by good aeration and relatively high 

 temperatures. The time necessary for complete humification of the various 

 compounds varied, albumin requiring a longer period than' lignin substances 

 containing tannic acid and chlorophyll. Starch was humified very slowly. 

 Water extracts of undecomposed woody substances were very active in humus 

 formation. Humus was not formed from proteids from substances containing 

 tannic acid and chlorophyll, and was formed from lignin only when that sub- 

 stance decomposed together with albumin. 



The effect of removing the soluble humus from a soil on its productive- 

 ness, W. AVeir {Jour. Agr. ^ri. [Kni/ldiid], 7 (V.Ho), Xo. 2, pp. 2.'iG-ioS). — 

 Experiments under laboratory conditions with a medium garden soil and a 

 typical loam soil to determine the influence of extracting the soluble humus 

 with fifth-normal hydrochloric acid and 2 per cent sotlium hydroxid on the crop 

 of wheat, mustard, and rye, and on the nitrate and ammonia content of the .soil 

 are reported. 



It was found that approximately equal total yields both of dry matter and 

 nitrogen were obtained over four succe.ssive crops from both untreated and 

 extracted soils. " It appears that the removal of the soluble humus had no 

 effect in diminishing the productiveness of the soil, in spite of the fact that the 

 soil used was known to respond to nitrogenous fertilizers. . . . Tiie removal of 

 the soluble humus increaseil the amount of ammonia but diminished that of 

 nitrates in the soil, and the sum of ammonia and nitrate was usually le.ss than 

 in the untreated .soil. The numbers of bacteria, however, were consl<lerably 

 increased. No marked difference was produced where 0.5 per cent untreated 

 soil was added to rephice-the bacterial flora that might have been destrt>yiHl by 

 the acid and alkali treatment." 



The loss of nitrogen and organic matter in cultivated Kansas soils and the 

 effect of this loss on the crop-producing power of the soil, C. O. Swanson 

 (Trans. Kana. AcnJ. Sci., 27 (191^). pp. 87-96).— The substance of this article 

 has been noted from another source (E. S. R., 33, p. 809). 



The soil: The principles of maintaining soil fertility, M. F. MnxEB (Bicn. 

 Rpt. Kans. Bd. Afir.. 19 {1913-1-',). pp. .',ri8-J,83. figs. 6).— The substance of this 

 article has been noted from another source (E. S. K.. 23, p. 31 S). 



How every plantation manager ought to analyse his soils, Leplak (Trop. 

 Life, 11 (1915), Xo. 10, pp. 185-188, figs. 5).— The use of so-calle<l pot culture 

 analyses to determine the nutritive element relatively in minimum in the soil, 



