19171 SOILS FERTILIZERS. 211 



in the fall at Crookston, Minn., from 1897 to October 1, 1916, and summaries 

 of observations on temperature, precipitation, clear and cloudy days, and pre- 

 vailing winds during the same period. The average date of the earliest killing 

 frost was September 24, the average growing period being 127 days. 



SOILS— FERTILIZERS. 



Soil survey of New Castle County, Delaware, T. M. Moreison, W. r>. Sew- 

 ABD, and O. I. Snapp (f7. S. Dept. Agr., Advance Sheets Field Operations Bur. 

 Soils, 1915, pp. S4, fig. 1, map 1). — This survey, made in cooperation with the 

 Delaware Experiment Station, deals with the soils of an area of 278,400 acres 

 in northern Delaware, two-thirds of which lie in the Coastal Plain and one- 

 third in the Piedmont Plateau. The surface includes a smooth to rolling plain 

 in which drainage is not yet thoroughly established, and a well-drained and 

 deeply dissected plateau. 



Including tidal marsh and meadow, 16 soil types of six series are mapped, 

 of which the Sassafras silt loam and loam and the Chester loam cover 26.5, 

 12.4, and 11.9 per cent of the area, respectively. 



Analyses of soils of Habersham County, W. A. Woesham, jb., D. D. Long, 

 L. M. Caetee, and M. W. Lowey (Bui. Oa. State Col. Agr., No. 114 (1911), pp. 

 40, figs. 5). — This report is intended to supplement the physical survey of the 

 soils of the county made in cooperation with the Bureau of Soils of the U. S. 

 Department of Agriculture, and contains data on the chemical composition of 

 both the surface soil and subsoil of the various soil types found in the county. 



" Taking the average of all soils of the county, analyses show the plant food 

 content to be as follows : Nitrogen, 0.0425 per cent ; phosphoric acid, 0.0616 ; 

 and potash, 1.0126. Nitrogen and phosphoric acid are relatively low in the 

 average soil of the county. Nitrogen is lowest, and, without doubt, the 

 limiting factor of crop production." 



Bremer County soils, W. H. Stevenson, P. E. Brown, and F. B. Howe 

 (Iowa Sta. Soil Survey Rpt. 1 (1917), pp. 48, pl. 1, figs, ii).— This is the first 

 of a series of reports on the soils of Iowa, and supplements the survey made 

 in cooperation with the Bureau of Soils of the U. S. Department of Agriculture 

 (E. S. R., 32, p. 317). 



Analyses of samples of the soils taken at depths of 6§ in., 6f to 20 in., and 20 

 to 40 in., are reported. " These results, as a whole, show that the soils of 

 Bremer County are not so richly supplied with necessary plant food as to assure 

 abundant crop growth continuously. ... In general the application of phos- 

 phorus, the increase of humus and of nitrogen, and the addition of limestone 

 are needed to make the soils of the county permanently fertile. Other essential 

 elements are apparently present in sufficient amounts for many years to come." 



General information regarding the principles of permanent soil fertility and 

 the results of greenhouse tests of some of the prevailing soil types of the county 

 are included. 



Soil survey of Richardson County, Nebraska, A. H. Meyee, P. H. Stewabt, 

 and C. W. Watson (U. S. Dept. Agr., Advance Sheets Field Operations Bur. 

 Soils, 1915, pp. 36, fig. 1, map 1). — This survey, made in cooperation with the 

 University of Nebraska, deals with the soils of an area of 348.S00 acres in south- 

 eastern Nebraska, the topography of which is in general rolling. The surface 

 drainage is considered to be adequate. The county lies almost entirely within 

 the glacial and loessial region, with only a small area belonging to the river 

 flood plain province. 



The soils include upland, terrace, and first bottom soils. Including river 

 wash and rough stony land, 14 soil types of nine series are mapped, of which 



