Nitrogen Fixation 9 
will be described a little later. This sample of surface soil with 
its incrustation yielded 22.466 per cent soluble in water. We will 
designate this orchard as No. 1. 
ANALYSIS II. 
WATER SOLUBLE PORTION OF SURFACE SOIL. Orchard No. 1. 
Per Cent. 
Calcic Sulphate . 4.462 
Potassic Sulphate . 2.557 
Sodic Sulphate . 39.852 
Sodic Chlorid . 12.626 
Sodic Nitrate . 29.114 
Silicic Acid . 0.054 
Loss (water, organic matter, etc.) . 4.789 
100.000 
The sodic nitrate or its equivalent constitutes 6.54 per cent of 
this surface soil. The first impression, especially in the field, was 
that salt, sodic chlorid, was the cause of the trouble, but the analy¬ 
sis reveals the presence of another salt which is beyond all question 
not only more toxic but present in more than double the quantity. 
The next sample was taken immediately below the preceding 
and included the next four inches of soil. The air dried soil yielded 
3.4 per cent of salts to water. 
ANALYSIS III. 
WATER SOLUBLE PORTION OF THE FIRST FOUR INCHES OF SOIL. 
Orchard No. 1. 
Per Cent. 
Calcic Sulphate . 11.769 
Magnesic Sulphate . 3.748 
Sodic Sulfate . 21.447 
Sodic Chlorid . 20.797 
Sodic Nitrate . 32.552 
Loss (water, organic matter, etc.) . 9.687 
100.000 
The organic matter in this sample was very abundant. The 
nitrates calculated as sodic nitrate equal 1.107 per cent of the air 
dried soil. 
The next sample was collected in a spot occurring in an alfalfa 
field, belonging to the same party and west of Orchard No. 1. This 
spot was' quite wet, though it had received no irrigation for about 
five months. The sample was taken in April, 1908, and to the 
depth of five inches. The air dried material yielded 7.778 per cent 
of its weight to water. The residue was quite deliquescent. Dried 
at no° it smelled faintly acid. 
