Apf. aS, 1903 
Toxicity and Antagonism of Alkali Salts in Soil 
335 
CALCIUM SULPHATE, SULPHUR, AND MANURE 
For the sake of completeness three well-known black alkali amend¬ 
ments were included in the experiment. Since none of them were toxic, 
the concentrations were made to range beyond the limits set by agri¬ 
cultural practice: 
Parts per millioii at ccmccntratioa— 
X 
3 
3 
4 
5 
CaS04 . 
1,000 
200 
2, 000 
I, 000 
3,000 
1,000 
S»ooo 
2,000 
6,000 
3»ooo 
10,000 
5»ooo 
zo, 000 
6,000 
15,000 
7,000 
20,000 
xo, 000 
20, 000 
Sulphur... 
Barnyard manure. 
Na-jCOa. 
The materials were mixed with the soil in a dry, powdered condition 
before the water was added. With the larger quantities of manure the 
soil was somewhat deficient in moisture because of the larger absorptive 
power of this treatment for water. The results for manure can not, 
therefore, be taken as final, since under other moisture conditions a 
different behavior might be expected. 
The experiment (fig. 13) shows that all three added substances are 
somewhat stimulating alone and that all have the power of counteracting 
partially the toxicity of sodium carbonate. This corrective action is 
accomplished in the lower carbonate treatments about equally well by all 
three materials, but with sodium carbonate at 7,500 parts per million 
calcium sulphate is the most effective and even seems to be a necessary 
component of the amending mixture. It should be noted that curves 
with 7,500 parts per million sodium carbonate represent average values 
for two entirely independent but closely concordant experiments. 
SUMMARY 
(1) The toxicity relations for wheat of certain alkali salts alone and 
in combination with each other have been investigated with special 
reference to the alleviation of black alkali trouble. 
(2) It has been shown that when a given concentration of sodium 
carbonate in sand is treated with an equal quantity of calcium sulphate 
or sulphuric acid, an appreciable lowering of the carbonate's toxicity is 
evident. This relation, however, is not so manifest in heavier soils. 
Sodium sulphate increases the toxicity of the carbonate under the same 
circumstances. 
(3) Either sodium chlorid or sodium nitrate could be substituted for 
sodium carbonate in the arrangement described above without changing 
the results. No antagonism between these salts and the sulphates 
could be detected in Greenville loam. 
(4) During 1921 each one of four different concentrations of sodium 
carbonate, alre^y incorporated in the Greenville soil, has been treated 
with five concentrations of the following substances, in groups of three; 
(1) Sulphuric acid, potassium sulphate, and sodium sulphate. 
(2) Hydrochloric acid, potassium chlorid, and sodium chlorid. 
(3) Nitric acid, potassium nitrate, and sodium nitrate. 
(4) Sodium chlorid, sodium sulphate, and sodium nitrate. 
(5) Sodium arsenite, sodium phosphate, and borax. 
(6) Calcium sulphate, sulphur, and barnyard manure. 
