314 



Journal of Agricultural Research 



Vol. XV, No. s 



be expected from the large amount of the crystalHne salt that appeared 

 at the surface of the tumblers of higher concentration. The sodium 

 carbonate shows the most interesting results. Over 80 per cent of the 

 lowest concentration (500 p. p. m.) has disappeared from the solution, 

 so far as its effect on the freezing point is concerned. It is also noticeable 

 that the greatest adsorption occurred in the Soils having the greatest 

 amount of organic matter as was to be expected from our other results. 

 The amount of the salt that could be detected in these soils by the ordi- 

 nary method of water extraction and titration is shown in Table VIII, 

 for comparison. The results agree remarkably well. This seems to 

 show that the organic matter in the soil not only neutralizes the basicity 

 of the carbonate but actually removes it from the solution altogether. 



TablB V. — The hicrease in the concentration of the soil solution by adding sodium chlorid 

 in various quantities to different soils. Increase in concentration determined by the 

 depression of the freezing point and expressed as parts per m,illion of sodium chlorid in 

 dry soil 



Soil. 



Concentration. 



Aver- 

 age. 



3,808 

 2,922 

 2,898 

 2,730 

 2,353 



2, 251 



I, 86s 

 i,8ii 

 1,545 

 1,620 

 1,829 

 1,719 

 1,509 

 1,997 



Salt added, .p. p.m. 



200 400 600 800 1 , 000 1 , 500 2 , 000 2 , 500 3 , 000 3 , 500 4, 000 



Sand 90, 

 Sand 80, 

 Sand 70, 

 Sand 60, 

 Sand 40, 

 Sand 30, 

 Sand 20, 

 Loam 90, 

 Loam 80, 

 Loam 70, 

 Loam 60, 

 Loam 40, 

 Loam 30, 

 Loam 20, 

 Loam lo, 



loam 10. 

 loam 20 . 

 loam 30. 

 loam 40 . 

 loam 60. 

 loam 70. 

 loam 80. 

 , clay 10. 

 , clay 20. , 

 , clay 30. 

 , clay 40 . 

 , clay 60. 

 , clay 70 . 

 , clay 80 . 

 , clay 90. 



231 

 527 



395 

 263 

 231 

 33 

 231 

 66 

 33 

 132 

 165 



560 

 650 

 856 

 296 

 650 

 593 

 560 

 132 

 428 

 231 

 165 

 296 

 395 

 132 

 626 



1,284 

 1, 120 

 626 

 790 

 72s 

 650 

 461 

 428 

 494 

 362 

 296 

 527 

 362 

 790 



1,251 



1,515 



1,284 



1,087 



1,021 



988 



1,087 



692 



560 



692 



494 



659 



889 



659 



922 



,844 

 , 219 

 ,437 

 ,251 



955 

 757 



922 



955 

 988 

 790 



1,284 



2,86s 

 2,569 

 2,601 

 2,009 

 2,470 

 1,976 

 1,844 

 1,614 

 1,647 

 1,284 

 1,350 

 1,51s 

 1,482 

 1,416 

 1,581 



3,886 

 4,677 

 3,359 

 3,425 

 3,326 

 2,734 

 2,668 

 2,569 

 2,07s 

 1,482 

 1,811 

 2,470 

 1,811 

 2, 042 

 2,30s 



5,302 

 6, 224 

 3>49I 

 4,446 

 3,952 

 3,195 

 3.326 

 2,832 

 2,602 

 2,07s 

 2,43 7 

 2,799 

 2,437 

 1,943 

 2.898 



6,389 

 6,587 

 5-730 

 5,072 

 4,512 

 4,150 

 3,557 

 3,293 

 3-195 



2, 700 

 2,964 

 3,063 

 3,030 



3, 260 

 3,656 



8,662 

 6,916 

 6,488 

 6,225 

 S, lOS 

 4,742 

 4,380 

 3-820 

 3-425 

 3,557 

 3-293 

 3,853 

 3-557 

 3-293 

 3-491 



8,958 

 9,090 

 5,269 

 7-443 

 5,368 

 5,269 

 5,171 

 4,183 

 4,380 

 3,65s 

 3,985 

 4,084 

 3,623 

 2,668 

 4,018 



Average. 



438 654 



2,709 3,331 



4>077 4.720 



S.149 



Table VI. — The increase in the concentration of the soil solution by adding sodium car- 

 bonate in various quantities to different soils. Increase in concentration determined 

 by the depression of the freezing point and expressed as parts per million of sodium 

 carbonate in dry soil 



