Oct. 4, 1915 
Effect of Alkali Salts in Soils on Crops 
15 
these salts can readily be determined by consulting figure 1. The number 
at the bottom of each triangle refers to the concentration of soluble salts 
in all the glasses of that triangle expressed in parts of anhydrous salt 
per million parts of dry soil. 
An examination of figure 2 shows that some seeds germinated in all 
glasses up to a concentration of 4,000 p. p. m., but that at 5,000 p. p. m. 
there was no germination in the glass having all sodium chlorid, and only 
germination in one of the glasses with three-fourths sodium chlorid. 
In the part of the triangle toward the sodium chlorid the germination 
gradually decreased as the concentration increased. The sodium car¬ 
bonate and sodium sulphate showed almost a complete germination up 
to 10,000 p. p. m., or 1 per cent of salt. 
NaiS0 < iooop.pm v ** co * 2,000ppm. 3.0Q0ppm. 4 .oooppm. s,oooppm . 
Cftec* 0 .A/o$<s/f 
. = One plant. — — 0.1 gm. dry matter. 
Fig. 2.—Diagram showing the number of wheat plants up and dry matter produced in 24 days on Green¬ 
ville loam with sodium sulphate, sodium carbonate, and sodium chlorid in different combinations and 
concentrations. 
The greater toxicity of sodium chlorid as compared with sodium car¬ 
bonate was somewhat of a surprise, since most of the literature on alkali 
considers sodium carbonate, or black alkali, as being by far the most 
harmful of the alkali salts. The results given here agree with those 
found in the experiments of 1912 and 1913 and are also borne out by 
the results shown in figures 7, 12, 17, 18, 19, 20, 21, and 22, where dif¬ 
ferent crops are compared. 
In the glasses that received sodium carbonate the surface was black 
with dissolved humus and was somewhat crusted, showing that the phys¬ 
ical condition had been injured. Notwithstanding this fact, seeds germi¬ 
nated in the soil and the plants grew for three weeks with no great injury 
except a slight blackening of plants at the surface of the soil with higher 
concentrations. 
Figure 3 shows results for the chlorids of potassium, calcium, and 
magnesium. These chlorids are not as toxic as the chlorid of sodium, 
5770°—15 - 2 
