20 RELATION OF LIME AND MAGNESIA TO PLANT GROWTH. 
2.75 per cent, of magnesia 1.71 per cent; the minimum of lime 0.87 
per cent, of magnesia 0.52 per cent. 
Recent analyses of soils of Oregon’ show a prevalence of magnesia 
over lime in certain districts; in one sample from Washington County 
even 0.90 per cent of magnesia for only 0.13 per cent of lime was found. 
Some analyses of soils of Nevada show a considerable excess of lime 
over magnesia.” This seems to be true also in Wyoming.’ 
Sous from British Columbia.*—Of thirteen samples analyzed, only 
four contained more magnesia than lime. The minimum of lime was 
0.73 per cent, of magnesia 0.32 per cent; the maxima, 1.86 and 1.55 
per cent, respectively. The ratio of lime to magnesia varies from 
2025700 ele: 
Soils of Texas.—The analyses of twenty-two soils from Texas” show 
generally a considerable preponderance of lime over inagnesia. This 
is also the case in Michigan.® Of twenty-nine different soils analyzed, 
not one contained more magnesia than lime, but the percentage of 
each of these oxides amounts in many cases to less than 1 per cent. 
Soils of Minnesota and North Dakota.—In Minnesota and North 
Dakota lime predominates in the majority of cases over magnesia, to 
judge from the analyses made thus far. Only in the southeastern part 
ot Minnesota magnesia predominates in most cases over lime. Snyder’ 
mentions as an average of two hundred Minnesota soils a lime content 
of 2.16 per cent and an average magnesia content of 0.55 per cent; 
hence the amount of lime is about four times as large as that of mag- 
nesia. In certain cases, however, the magnesia content exceeded the 
lime content by one-half. The minimum lime observed was 0.16 per 
cent, that of magnesia 0.10 per cent. 
As to North Dakota, there exist soils exceedingly rich in lime in the 
valleys of the Cheyenne, of the Red River, and of the Mouse River. 
Jn these cases the magnesia content remains below 2 per cent, while 
the lime content amounts from 18 to 23 per cent.* A case with a rela- 
tively large excess of magnesia over lime was observed in the James 
River Valley, namely, 0.14 per cent of lime for 1.38 per cent of mag- 
nesia; hence the amount of magnesia exceeded that of lime nearly ten- 
fold. Of thirty cases in all, the magnesia exceeded the lime only in 
aight. ; 
‘Oregon Agr. Exp. Station Bul. No. 20. 
* Nevada Agr. Exp. Station Bul. No. 19. 
3 Wyoming Agr. Exp. Station Bul. No. 6. 
‘Experimental Farms Report, 1895, p. 200. These soils were never manured_ 
except incidentally by the droppings of animals when in pasture. 
> Texas Agr. Exp. Station Bul. No. 25. 
§ Michigan Agr. Exp. Station Bul. No. 99. 
‘Minnesota Agr. Exp. Sta. Bul. No. 41, p. 32. 
5 Analyses of A. F. Ladd, North Dakota Agr. Exp. Sta. Bul. No. 22. 
