SOILS — FEKTILIZEKS. 209 



organisms developing at 20° C on gelatin were generally found to be under 50 

 per cubic foot, rarely over 100 per cubic foot. The number of those developing 

 at 37° was rarely over 50 per cubic foot. The number of streptococci was 10 per 

 100 cu. ft. 



SOILS— FERTILIZERS. 



Soil reconnoissance in Alaska, with, an estimate of the agricultural pos- 

 sibilities, H. H. Bennett and T. D. Rice {U. 8. Dept. Ayr., Advance Sheets 

 Field Operations Bur. Soils, I'JJ-'f, pp. 202, pis. 3S, maps Jf). — This report, issued 

 September 20, 1915, deals with the soils and agricultural possibilities of the 

 Cook Inlet-Susitna, Yukon-Tanana, and Copper River regions of Alaska. 



The Cook Inlet-Susitna region includes approximately 6,000 square miles of 

 land, comprised in the plain-like country and adjacent bench lands bordering 

 Cook Inlet from Kachemak Bay northward and extending up the Susitna and 

 Matanuska valleys. " At least one-third of this area . . . consists of arable 

 land possessing topographic and drainage characteristics and chemical and 

 physical properties quite favorable to farming. . . . The remainder of the low- 

 laud country largely represents Muskeg or marsh, isolated areas in the Muskeg, 

 and areas of unfavorable topography. Extensive drainage operations will be 

 required to reclaim the marsh land, and to make available the included well- 

 drained land." " The Cook Inlet-Susitna benches and lowlands embrace a con- 

 siderable variety of soils ranging in composition from silt loam through fine 

 sand to peat, and in drainage, from well-drained bench land to water-soaked 

 marsh." Exclusive of Muskeg and muck, there are two broad soil divisions in 

 the region, namely, bench land soils and stream bottom soils. Of these the 

 Knik loam and fine sandy loam soils are the most extensive. 



The Yukon-Tanana region comprises (1) the lowlands of the lower Tanana 

 River, from the vicinity of McCarty to the Yukon River, known as the Tanana 

 Flats; (2) the lowlands of the Yukon River, chiefly comprised in the Yukon 

 Flats; and (3) the area of highlands or hill country between the Tanana and 

 Yukon lowlands, the Yukon-Tajiana uplands. " The lowest estimated area of 

 available farming land in this region is 4,500,000 acres. In this estimate only 50 

 per cent of the 7,000 square miles of the lower Tanana bottoms is included and 

 less than 25 per cent of the uplands lying to the north of the Tanana River." 

 The soils of the Tanana bottoms are mainly sandy and silty and are flat and 

 mostly well drained. In the hills north of the Tanana bottoms is an area of 

 approximately 500,000 acres of deep silt loam soil which is considered to be the 

 best soil in Alaska. These soils are well drained and have good moisture-hold- 

 ing capacity. " There are still larger areas of other cultivable soils on the slopes 

 of the hill country." In the Yukon-Tanana region seven of the principal soil 

 types are mapped of which the so-called Gilmore soils and stony mountainous 

 areas, Tanana soils, and Yukon soils are the most extensive. 



The Copper River regions include the Copper River Basin and the Copper 

 River Delta. The former is a broad expanse of plain-like country almost com- 

 pletely inclosed by mountains and containing a large area north of Copper 

 Center the topography of which is favorable for agriculture. " The principal 

 soil here, however, is not so favorable, being predominantly of a clayey char- 

 acter, and so stiff and probably cold-natured that it would be difficult to till." 

 The soil of the Copper River Delta " represents a mixture of the recent glacial 

 outwash, chiefly gravel and sand, with the sand and silt of the Copper River 

 alluvium." 



A comparison of Alaska with Finland and parts of Siberia is also included. 



