Nov.4. i9i8 Soil Factors Affecting the Toxicity of Alkali 



315 



TablB VII. — The increase in the concentration of the soil solution by adding sodium sul- 

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

 the depression of thefreeziyig point and expressed as parts per million of sodium sulphate 

 in dry soil 



Soil. 



Concentration. 



Averj 

 age. 



6,775 



7.03I 

 5-980 

 5- 900 

 5.884 

 4.779 

 4,026 

 3.806 

 3.638 

 3,636 

 3,224 

 3,557 

 2,660 

 3,349 



Salt added, .p.p.m. 



500 1,000 2,000 3,000 4,000 5,000 6,000 7,oco 8,000 9,000 10,000 



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 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. 

 I, clay 80. 



clay 90 . 



1,306 

 2,743 

 784 

 261 

 849 

 914 

 588 

 784 

 391 

 784 

 719 



2,613 



2,090 



2,155 



1,698 



1, 110 



849 



1, 241 



1,045 



784 



719 



I, 241 



719 



1,306 



784 



613 



98s 



3,789 



3,070 

 894 

 678 



2, 221 

 090 

 698 



1,960 

 894 

 960 



1,829 

 980 

 045 



6,663 

 4,703 

 4,376 

 2,874 

 3,397 

 2-939 



2, 809 

 2,548 



2,939 



2,482 

 2,090 

 2,678 

 1,502 

 1,894 



8,492 

 9,472 



7,051 

 4,638 

 4,246 

 4.050 

 3-266 

 3,201 

 2. 809 

 3,331 

 3,00s 

 3; 005 

 1,829 

 1,960 



9,863 

 9,798 

 9,014 

 6,597 

 5,095 

 5,160 

 4.050 

 4,181 

 3,723 

 3,593 

 3.331 

 3,397 

 2.678 

 2,678 



9,994 



4,512 

 7,708 

 8,165 

 5,748 

 4.703 

 4-442 

 3,723 

 4,181 

 3, 266 

 3-985 

 3-331 

 3,919 



9,602 

 9,341 

 9,994 

 8,230 

 9, 210 

 6,663 

 5-095 

 4,964 

 4,703 

 4,703 

 3-789 

 4,311 

 3-593 

 4. 115 



7,838 

 9,733 

 9, 145 

 9,080 

 9,537 

 6,989 

 6,597 

 5,618 

 6, 205 

 5,356 

 5, 160 

 S>552. 

 3-984 

 4,246 



7.773 



7,773 

 7,773 

 9,537 

 9, 602 

 7,969 

 6,662 

 6, 205 

 5,879 

 5,814 

 5,291 

 S,6i8 

 4,442 

 5,878 



8,034 

 7,838 

 8,361 

 13,000 

 II, 104 

 9,798 

 7,381 

 7,447 

 6,933 

 6-597 

 6. 140 

 6,597 

 5.291 

 5,879 



Average. 



1,314 2,221 



3,135 



5i233 



5,468 



6,308 



6,788 6,872 



Table VIII. — Amount of sodium carbonate that could be detected by water extraction in 

 different soih to which it had been added in various quantities 



Soil. 



Concentration. 



Aver- 

 age. 



Salt added, .p.p.m. 



500 1,000 2,000 3,000 4,000 s.ooo 6,000 7,000 8,000 9,000 10,000 



Sand 90, 

 Sand 80, 

 Sand 70, 

 Sand 60, 

 Sand 40, 

 Sand 30, 

 Sand 20, 

 Loani 90 

 Loam 80 

 Loam 70 

 Loam 60 

 Loam 40 

 Ivoam 30 

 Loam 20 

 Loam 10 



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 . 



170 

 250 

 148 

 170 

 42 

 170 



85 

 170 

 170 

 254 



60 

 170 



S94 

 381 

 275 

 255 

 254 

 170 

 170 

 212 

 212 

 339 

 255 

 254 



467 



891 

 896 

 615 

 552 

 551 

 636 

 510 

 467 

 466 

 806 

 721 

 424 

 339 

 442 

 594 



1,484 



1,399 



1-293 



1,018 



848 



976 



934 



848 



805 



1,060 



1,188 



424 



593 



823 



1,442 



2,417 

 2,077 

 1,674 

 1-527 

 1, 229 

 1,31s 

 1-315 

 1,018 

 1, 102 

 1,230 

 1,357 

 1,187 

 996 

 1,205 



3,859 

 2,059 

 2, 141 

 1,993 

 1,696 

 1,654 

 1,485 

 1,569 

 1,314 

 1,696 

 1,781 

 1,654 

 1-738 

 1,586 

 1,569 



3,307 



3,477 

 3,243 

 2,375 

 1,865 

 2,078 

 1-951 

 1-823 

 1,865 

 1.908 

 2,078 

 1.696 

 2. 120 

 1,671 

 2.078 



5,682 

 3,010 

 3,582 

 3.223 



2, 289 

 2,714 

 2. 121 

 2,035 

 2,077 

 2,020 

 2,460 



1,866 

 2, 162 

 2,350 

 2,714 



5, 088 

 4,452 

 4-346 

 4, 113 

 2,883 

 3,265 

 2,801 

 2,544 

 2,628 

 2,671 

 2,672 

 2,205 

 3-09S 

 2,774 

 3-096 



6,784 

 5,427 

 4,388 

 4,601 

 3,519 

 3,774 

 3,478 

 2,841 

 3,095 

 3,09s 

 3,265 

 3,350 

 2,756 

 3,198 

 3,816 



6,784 

 6,445 

 5,109 

 4,198 

 3,731 

 3,859 

 3,732 

 3,26s 

 3-392 

 3-731 

 3.901 

 3.901 

 3-604 

 3,961 

 4.240 



3,369 

 2, 716 

 2,437 

 2,184 

 1,718 

 1,874 

 1,689 

 1,530 

 1,545 

 1-695 

 1.804 

 1,557 

 I, 609 

 1,644 

 1,916 



Average. 



1,009 



1,369 



1,853 



2,236 



2,687 



3,242 



3,826 4,257 



RELATIVE TOXICITY OF THE SALTS 



Turning our attention to the relative toxicity of the three salts and 

 averaging together the yields of dry matter from all tumblers in series 

 having the same salt content, we obtain the results shown in figure 27, 

 which shows the percentage of normal yield from all soil types and 

 moisture contents for each concentration of each salt as added. It will 

 be noticed that up to 1,000 p. p. m. all the salts are beneficial in the 

 action, the carbonate being especially so. After 1,500 p. p. m. all the 

 salts become increasingly toxic, the chlorid most so and the sulphate least, 

 with the carbonate about halfway between. 



Two very noticeable features of these results are that the chlorids 

 average about twice as toxic as the carbonate on a basis of what was 



