SOILS FERTILIZERS. 727 



food in the surface soil. An application of 150 lbs. per acre of sodium nitrate 

 to wheat, barley, and oats more than doubled the yield of these crops. Appli- 

 cation of sodium nitrate (200 lbs. per acre) also greatly increased the yield of 

 potatoes. 



La Salle County soils, C. G. Hopkins et al. {Illinois 8ta. Soil Rpt. 5, -pp. 

 45, pis. 4, figs. 5). — This is the fifth of the series of the Illinois county soil 

 reports and, as in other reports of the series, deals briefly with physiography, 

 topography, and formation of the soils, and more fully with soil material and 

 soil types, chemical composition of the soils, and field tests of the fertilizer 

 requirements of certain of the soils (in this case the brown silt loam). 



" La Salle County is located in the north central part of the early Wisconsin 

 glaciation. The soils of the county are divided into five classes as follows: 



"(1) Upland prairie soils, rich in organic matter. These were originally 

 covered with the wild prairie grasse.s, the partially decayed roots of which have 

 been the source of the organic matter. The flat prairie land contains the 

 higher amount of this constituent because it was largely preserved from decay 

 by the presence of water. 



"(2) Upland timber soils, including those zones along stream courses over 

 which forests once extended. The timber laud contains much less organic 

 matter, because the large roots of dead trees and the surface layer of leaves, 

 twigs, and fallen trees were burned by forest fires or suffered almost complete 

 decay. 



"(3) Terrace soils, or second bottom land, representing the soils formed on 

 fills of either silt or gravel or the flood plain of a stream when it flowed at a 

 higher level than at present. 



"(4) Swamp and bottom lands, which include the lands that overflow along 

 streams and a few small areas of swamps on the upland. 



"(5) Residual soils, formed by the decomposition of rocks in place. The 

 entire area of this class is only 2* square miles." 



" The most significant fact revealed by the investigation of the La Salle 

 County soils is the low phosphorus content of the common brown silt loam 

 prairie, a type of soil which covers more than three-fourths of the entire 

 county. . . . 



" With 6,000 lbs. of nitrogen in the soil and an inexhaustible supply in the 

 air, with 34,000 lbs. of potassium in the same soil and with practically no acidity, 

 the economic loss in farming such land with only 1,300 lbs. of total phosphorus 

 in the plowed soil can be appreciated only by the man who fully realizes that 

 the crop yields could ultimately be doubled by adding phosphorus, without 

 change of seed or season and with very little more work than is now devoted 

 to the fields." 



The selection of soils in the Tropics, F. Wohltmann {Jalirh. Deut. Landw. 

 Gesell., 2S {1913), No. 1, pp. 246-2G2; ahs. in Rev. Sci. [Paris}, 51 {1913), II, 

 No. 10, pp. 311, 312). — It is shown that the success of the settler in the Tropics 

 is especially dependent upon the judgment he exercises in selecting his soil. 

 It is necessary for this purpose to know the climatic and geological conditions 

 under which the soils were formed, their character at different depths, mechani- 

 cal and chemical composition, and bacteriological properties. Chemical analy- 

 ses of a Kamerun soil at different depths are given and the kinds of soil 

 adapted to various tropical crops, including cacao, coffee, muskat nut, vanilla, 

 sisal, cotton, jute, caoutchouc, peanuts, coconut, date, oil and sago palms, tubers 

 of various kinds, bananas, corn, millet, and tobacco are described. 



Malayan soils, M. Barrowcliff {Agr. Bui. Fed, Malay States, 1 (1913), 

 Nos. 6, pp. 210-216; 12, pp. ^iS-^28).— Mechanical and chemical analyses of 



