VARIATION IN THE CHEMICAL COMPOSITION OF SOILS. 5 



The method used for determining phosphorus was tested on 

 synthetic mixtures, and as a result it is estimated that the figures 

 given for phosphoric acid are within 0.02 per cent of the actual 

 amount present. 



Blank determinations were made in all cases, and the silica and 

 magnesia corrected for impurities. The quantity of silica in the 

 iron and alumina group precipitate had been found constantly so 

 small in earlier work that no correction was made for it here. 



RESULTS OF ANALYSES. 



The results of these analyses are given in the following table. 

 The results are stated in percentage of the soil dried at 105° C. 



Table 1. — Chemical analyses of certain American soils. 

 [Analyses by W. O. Robinson and L. A. Steinkoenig; nitrogen determinations by Wm. H. Fry.] 





Great Plains Province. 



Glacial and Loessial Province. 



Constituent. 



Colorado sand. 



Oswego silt 

 loam. 



Knox silt loam. 



Memphis silt 

 loam. 



Memphis silt 



loam, smooth 



phase. 





(1) 



0-14 

 inches. 



(2) 



14-36 

 inches. 



(3) 



0-14 

 inches. 



(4) 



14-36 

 inches. 



(5) 



0-14 

 inches. 



(6) 



14-36 

 inches. 



(7) 



0-6 

 inches. 



(8) 



6-36 

 inches. 



(9) 



0-6 

 inches. 



(10) 



6-36 



inches. 



Si0 2 



P. ct. 

 78.85 

 0.32 

 9.68 

 2.72 

 0.031 

 0.94 

 0.72 

 2.31 

 2.02 

 0.11 

 0.07 

 0.10 

 2.28 



P. ct. 



76.84 

 0.36 



11.09 

 3.21 

 0.036 

 1.08 

 0.62 

 2.57 

 2.06 

 0.09 

 0.20 

 0.07 

 2.35 



P. ct. 



71.38 

 0.68 



12.29 

 3.63 

 0.056 

 1.09 

 0.36 

 2.28 

 1.14 

 0.10 

 0.12 

 0.20 

 7.11 



P. ct. 



68.74 

 0.70 



14.45 

 5.00 

 0.057 

 0.88 

 1.12 

 2.20 

 1.12 

 0.08 

 0.18 

 0.13 

 5.49 



P. ct. 



76.81 

 0.70 

 9.73 

 3.26 

 0.068 

 0.92 

 0.60 

 2.10 

 1.74 

 0.12 

 0.11 

 0.14 

 4.09 



P. ct. 



75.95 

 0.70 



11.16 

 3.99 

 0.067 

 0.92 

 0.74 

 1.60 

 1.74 

 0.10 

 0.02 

 0.06 

 2.77 



P. ct. 

 81.13 

 0.78 

 8.52 

 2.92 

 0.027 

 0.31 

 0.39 

 1.78 

 0.52 

 0.08 

 0.03 

 0.11 

 3.40 



P. ct. 



73.58 

 0.80 



12.25 

 5.02 

 0.067 

 0.36 

 0.78 

 2.14 

 0.71 

 0.14 

 0.02 

 0.07 

 4.01 



P. ct. 

 80.78 

 0.86 

 8.48 

 3.05 

 0.036 

 0.27 

 0.45 

 1.84 

 0.72 

 0.10 

 0.03 

 0.06 

 3.20 



P. ct. 



72.67 



Ti0 2 



0.79 



A1 2 3 



12.80 



Fe 2 3 



5.58 



MnO 



0.052 



CaO 



0.26 



MgO 



0.84 



K 2 



2.08 



Na 2 



56 



P 2 5 



0.13 



S0 3 



04 



N 



05 



Loss on ignition 



3.96 



Constituent. 



SiOo.. 

 Tiot. 

 A1„0,. 

 Fe 2 />, 

 MnO. 

 CaO.. 

 MgO. 

 KoO.. 

 Na 2 0. 

 P 2 0„ 



N."!.. 

 Loss 

 tion 



on lgni- 



River Flood Plains Province. 



Coastal Plain Province. 



Cahaba fine 

 sandy loam. 



(11) 



0-12 

 inches. 



(12) 



12-36 

 inches. 



P.ct. 

 91.39 

 0.52 

 3.72 

 0.97 

 0.065 

 0.21 

 0.09 

 0.90 

 0.12 

 0.06 

 0.06 

 0.05 



1.53 



P.ct. 



73.25 

 0.69 



13.79 

 4.88 

 0.024 

 0.15 

 0.34 

 1.08 

 0-10 

 0.05 

 0.05 

 0.10 



5.18 



Cahaba very 



fine sandy* 



loam. 



(13) 



0-12 



inches. 



P.ct. 



93.29 

 0.42 

 2.45 

 0.78 

 0.086 

 0.15 

 0.01 

 0.45 

 0.03 

 0.06 

 0.10 

 0.05 



2.12 



(14) 



12-36 

 inches. 



P.ct. 

 91. S3 

 0.46 

 3.83 

 1.19 

 0.079 

 0.12 

 0.09 

 0.58 

 0.05 

 0.05 

 0.13 

 0.03 



1.61 



Norfolk sand. 



(15) 



0-8 

 inches. 



P.ct. 

 94.81 

 0.51 

 1.42 

 0.60 

 0.028 

 0.19 

 0.01 

 0.08 

 0.12 

 0.10 

 0.08 

 0.05 



2. 33 0. 79 



(16) 



8-36 



inches, 



P.ct. 

 97.01 

 0.53 

 1.31 

 0.52 

 0.005 

 0.03 

 0.01 

 0.08 

 0.08 

 0.03 

 0.06 

 0.02 



Orangeburg 

 sand. 



(17) 



0-10 

 inches. 



P.ct. 



96.18 

 0.35 

 1.70 

 0.59 

 0.016 

 0.08 



Trace. 

 0.08 



Trace. 

 0.04 

 0.07 

 0.06 



1.03 



(18) 



10-36 

 inches. 



P.ct. 



91.86 

 0.41 

 4.11 

 1.32 

 0.011 

 0.05 



Trace. 

 0.10 



Trace. 

 0.04 

 0.10 

 0.02 



1.75 



Orangeburg 

 sandv loam. 



(19) (20) 



12-36 

 inches, jinches. 



P.ct. 



94.32 

 0.40 

 2.13 

 0.85 

 0.054 

 0.05 



Trace. 

 0.10 

 0.29 

 0.05 

 0.07 

 0.03 



P.ct. 



77.20 

 0.66 



12.75 

 3.18 

 0.027 

 0.09 

 0.08 

 0.14 

 0.20 

 0.08 

 0.11 

 0.08 



5. 19 2. 00 



Greenville 

 sandy loam. 



(21) 



0-10 



inches. 



P.ct. 



92.42 

 0.41 

 2.78 

 1.55 

 0.030 

 0.01 



Trace. 

 0.13 

 0.26 

 0.05 

 0.02 

 0.02 



(22) 



10-36 

 inches. 



P.ct. 



73.03 

 0.70 



16.11 

 5.11 

 0.016 

 0.10 

 0.23 

 0.14 

 0.26 

 0.06 

 0.05 

 0.03 



5.46 



