The Soil. 
11 
distinctive properties to it. These would remain if the others 
should be eliminated. 
§ 17. The relative amount of magnesic salts which are present 
in the ground waters before and after the soil has been cultivated, 
also before and after the application of manure, indicate that there 
is a series of reactions taking place which result in eliminating these 
salts as end products. The growing of crops, the cultivation and 
irrigation of the soil, also the application of manure, accelerate 
these changes. The readiness with which these reactions take 
place, especially if they be beneficial to the crop, must, to a con¬ 
siderable extent, be a measure of the soil’s fertility. 
THE BIOLOGY OF THE SOIL NOT STUDIED. 
§ 18. The soil is not only the theater of a wide range of 
chemical reactions, some dependent upon and some independent of 
the living organisms present, but it is also the home of an abundant 
microscopic life, constituting a veritable world of itself. 
§ 19. The biological conditions of the soil ought, in this study, 
to have been taken up with thoroughness, but it has been im¬ 
possible. We will present the results obtained by such study as we 
have been able to devote to the soil in the following pages. 
§ 20. The purely agricultural features of this study have 
already been given in Bulletins 46 and 58. These bulletins have 
treated exclusively of the crops grown on the soil, especially of the 
effects of the alkali on the growth and ripening of the plant, on the 
amount of ash constituents taken up, etc. In this bulletin we shall 
treat of the soil, and in a subsequent one of the ground waters, the 
irrigation water and its changes. 
THE PHYSICAL CHARACTER OF THE SOIL. 
§ 21. Beginning at the west end of the plot the soil is a light 
loam. This passes into a paludal soil rich in alkali, succeeded by 
a gravelly, claye} 7 soil, which has resisted treatment to a greater ex¬ 
tent than any other portion of the plot. The most eastern section 
of the plot is the lowest, the wettest, and, judging by the abundance 
of the salts which effloresce, the most strongly alkalized one. The 
extreme western section is the only one in which there is a subsoil 
within six feet of the surface. The character of the eastern most 
section was that of a very tenacious, alkalized clay, which, when 
moulded to a form and dried, became exceedingly hard. It was a 
most unpromising soil to attempt to do anything with. The plot 
has a slope to the eastward of about four feet in 600. There is a 
stratum of coarse sand and gravel underlying the whole of the plot 
at a depth of about six feet. The surface is fairly even, with a 
slight depression running diagonally from near the southwest corner 
to the north side, a little west of the centre. 
