lt>ini son... FERTILIZE] | 1 !♦ 



It is stated that the Isolatl f organic substance* from the soil Hid to be 



parti; toxic to plants should nol be overemphaal bo proof is available 



thai Buch Bubstances occur in the dark-colored, add bumus of coniferous 1 



in many places nitrification was so rapid thai considerable s anti I 



nitrogen accumulated In the covering vegetation, this being q tally marked in 



dense beech, elm, oak, ash, and alder forests with moving underground water 

 In the higher mountain regions the soil covering contained n large quanl 

 of nitrogen, while In woodlands and spruce forests with gri I cover! i 



the nitrogen of the humus nitrified withoul :i resulting accumulation "f nltroi 



in tlie layer. Plant associations on bare rockj soils were often c posed "f 



nltrophllous species, which accumulated nitrogen In their tissues, in pine 

 forests having a covering of lichens and mosses, nitrification did not occur, nn.i 

 the decomposition of the dead covering gave rise to the formation <>t ammonia 

 and its compounds. Natural soils were capable of accumulating as much nitric 

 nitrogen as ordinary cultivated soils. 



Nitrification was found to be Influenced not only by th<> origin "f the 

 to a large extent but also by the climate. Since the degree of nitrification 

 constituted an important factor in determining the composition of the pi 

 associations of a Riven soil, those factors affecting the formation of the s,,j| 

 might have a decisive influence on this composition. A suitable foresl -v-mm, 

 therefore, should make it possible to thin the forests in such B way a. t,, favor 

 soil nitrification, thus assuring a higher yield of wood. Ft is stated, however, 

 that good yields of pine and Bpruce could be obtained on soils having no nitrate 

 formation. In the latter ease, the rate of growth appeared to be proportional 

 to the rate of ammonification. 



The shrinkage of soils ( West Indian Hut.. 11 {1918), No. 2. pp. /07-//S. tip*. 

 2). — This is an account of work done by Tempany and previously noted from 

 another source (E. S. R., 38, p. 321). 



[Report of soil investigations in Montana |. BS. BURKE (Montana St*. Upt. 

 1917. pp. 288-240). — The nature of the soil fertility work in progress at the 

 station and in cooperation with farmers throughout the State is brieflj de- 

 scribed, and the construction of a geological map of .Montana is noted. It is 

 stated that observations covering a period of seven years showed little dlfferei 

 in the amount of nitrates present in the soil where different cropping systems 

 had been practiced, including alternate summer fallow and crop, B rotation "f 

 corn, peas, fallow, and wheat, and continuous cropping to corn or sugar beets. 

 Where alfalfa, brome grass, or wheat had been grown continuously the soils 

 did not contain so large amounts of nitrates as occurred with the various crop 

 ping systems noted above. 



Soil survey of Monroe County. Ala.. II. C. Smith. A. 1,. Paikick. and J I" 

 Strot-d (T. g. Dept. Apr.. IdV. Sheets Field OpCT. Bur. SoiU, 1916, pp. • >•?. ' 

 .?. map 1). — This survey, made In cooperation with the State of Alabama, deals 

 with the soils of an area of 647,680 acres situated in the southwestern part of 

 the State, and lying entirely within the Gulf Coastal Plain. The topography Of 

 the county ranges from prairie-like to rough, about one-sixth being nntillable, 

 one-sixth fiat land, and the remainder rolling to hilly. Approximately s " per 

 cent of the area is upland. Natural drainage is generally well established. 



The upland soils of the county have been derived from lime-bearing ro< 

 noncalcareous siliceous rocks, and from unconsolidated deposits of sand. clay, 

 and gravel. In addition, areas of terrace soils, derived from old alluvium, are 

 found largely above ordinary overflow, while flood-plain soils occur which are 

 overflowed several times annually. Exclusive of meadow. 27 -"ii types "f 17 

 series are mapped. Orangeburg fine sandy loam. Huston gravelly sandy loam, 



