The Waters of the Rio Grande 
55 
SOIL SAMPLES TAKEN TO PROVE RESULT 
In order to prove this question further, two series of soil samples 
were taken along the same lines that the water samples were taken. 
It is readily foreseen that soil samples taken to represent so long a 
stretch of land, the lines aggregating more than 30 miles, will vary 
greatly and it would be no matter for surprise if some of them seemed 
to contradict’ the statements made. This, fortunately, is not the case, 
for we find that our results agree very well with the facts as seen in 
the field. 
In the following statement of results, I shall give the conditions 
of the land as of more interest than the locality and state the results 
in parts per million of air-dried soil. 
Sodic carbonate present to the extent of 400 p.p.m. is injurious 
to most crops and I doubt whether any cultivated crop can endure as 
much as 500 p.p.m. I think that it is perfectly safe for the general 
reader to use these figures as guides in judging the results given in 
the following table: 
ALKALINITY OF SOIL EXTRACTS 
Sodic Carbonate 
(Black Alkali) 
Condition of land or crop in parts per million 
An old “gone-back” ranch. 865.0 
Land in bad condition, crops failed. 375.0 
Land barren for some years. 722.0 
Land barren . 925.0 
Barren, sandy soil. 5103.0 
Alfalfa field, stand good . 144.0 
Old alfalfa, stand medium. 200.0 
Alfalfa field, stand good. 259.0 
Sandy soil, alkali grass, some sweet clover. 121.0 
Diked and flooded soil. 109.0 
Sandy loam, uncultivated... 253.0 
Oats, a failure in 1916. 609.0 
Deserted land . 200.0 
Wholly unproductive, though under good treatment. 510.0 
Wholly unproductive and has been for many years. 3222.0 
Land just surfaced. 200.0 
Flooded 1916, planted to rye, poor stand..../ . 398.0 
Flooded 1916, planted to rye, not much living. 410.0 
Planted to peas 1916, died . 633.0 
The preceding samples represent both good and bad conditions 
as they are found throughout this area. 
Unfortunately, the problem, like most of our agricultural prob¬ 
lems, is not a simple one, for there are several factors playing their 
respective parts. The one here pointed out, sodic carbonate, is, with¬ 
out doubt, the principal one affecting the conditions in this area, 
though it has not previously beeff pointed out, or even given serious 
recognition. Excessive water alone has been, charged with the ruin of 
the land and drainage urged as its greatest need. I am among those 
who do not believe this. 
