268 



Journal of Agricultural Research 



Vol. XVI, No. lo 



Table II. — Nitrogen content of soil at different levels on plots 2 and j, illustrating the 

 degree of concordance of the daiafrotn duplicate sets of composite samples 



Depth of section. 



Plot, 



Set A. Set B. Difference 



Plot 4, 



Set A. Set B. Difference 



Inches. 



I to 6 



7 



8 



9 



lO 



II 



12 



13 to 15 



16 to 18 



Per cent. 

 O. 229 



■237 

 .230 

 . 227 

 . 212 

 .199 

 . 187 

 .165 



Per cent, 

 o. 240 



.244 



• 233 



. 216 



• 197 

 . 184 

 .174 



• 143 

 . 114 



Per cent. 

 O. Oil 



. 007 

 .003 

 . on 



.015 

 .015 

 .013 



. 022 

 . 007 



Per cent. 



O. 182 



. 166 



. 167 



. 160 



■ 147 

 . 124 

 . 120 

 . 096 

 .078 



Per cent, 

 o. 178 



. 170 

 .158 

 . 141 

 . 142 

 . 127 

 . 112 

 .099 

 .087 



Per cent, 

 o. 004 

 . 004 

 . 009 

 . 019 

 .005 



• 003 

 .008 

 .003 

 . 009 



UNIFORMITY IN TEXTURE 



The moisture equivalents of the soil from the different levels are re- 

 ported in Table III. Those for the first 12 inches were determined on 

 composites made by combining equal weights of the duplicate samples 

 reported in Table II, and, hence, they represent composites of 24 indi- 

 vidual samples from each plot. The data for the second and third feet 

 are from composites from 6 borings on each plot. 



Table III. — Moisture equivalents of soil at different levels 



Depth of section. 



I to 6 inches... 

 Seventh inch. 

 Eighth inch . . 

 Ninth inch. . . 

 Tenth inch . . . 

 Eleventli inch 

 Twelfth inch . 

 Second foot . . 

 Third foot 



Plot 6. 



Per cent. 

 24-3 

 24-3 

 24- 5 

 24. 2 

 24. o 



23.2 



23. o 



24-3 



22. 



As was to be expected from the content of organic matter, the lowest 

 values within the surface foot are shown by plot 4 and the highest by 

 plot 3. The differences in the moisture equivalent are very slight com- 

 pared with those in nitrogen and organic matter; while the nitrogen in 

 the surface foot of plot 3 exceeds that in plot 4 by 38 per cent and the 

 organic matter shows a corresponding difference of 40 per cent, the mois- 

 ture equivalent is only 7 per cent higher. In the case of the second and 

 third feet, the crop history of the plots appears to have exerted no appre- 

 ciable influence upon the moisture equivalent, the differences shown in 

 these levels being within the limits of error in sampling. 



