The Ground Water. 
5 
to experiment on, and which was chosen as representative of much 
land in Colorado which is neither so wet as to be untillable nor so 
strongly alkalized as to be hopeless, and yet was strongly enough 
impregnated with salts to yield, under favorable conditions, incrus¬ 
tations reaching a half inch in thickness. 
§ 7. Parts I and II of this study deal exclusively with the 
effects of these conditions on the growth and composition of sugar 
beets, the crop chosen to grow on this land, because we thought it 
probably more tolerant of the conditions than any other crop which 
would at the same time serve the other purposes of our study. 
§ 8. Part III deals with the soil, giving an account of the 
mechanical and chemical effects resulting from our cultivating and 
manuring it. In this bulletin, Part IV of our study, we shall pre¬ 
sent the results of our observations on the ground water, the changes 
in the water used for the purpose of irrigating, the salts removed, 
etc. I shall confine myself in this bulletin to the subject of water, 
as in Part III I confined myself to the subject of the soil. 
§ 9. I have stated the general condition of the plot at the be¬ 
ginning of the experiments; I have stated the reasons which in¬ 
duced us to choose this plot of ground as well as the crops to be 
grown thereon; and in Part III I have given the condition of the 
soil at the end of our experiments, which is summed up by stating 
that the store of plant food in the surface soil, taken to a depth of 
ten inches, was actually increased. This, however, was the lesser 
part of the improvement, the greater part lay in the betterment of 
the general conditions, whose best features cannot be shown by 
chemical analysis or expressed in any formula. The strongest 
and most interesting point in this connection is that the conditions 
of water supply and drainage have remained the same throughout 
the experiment. The ground has subsequently been drained, in 
part, at least. 
§ 10. The amount of water in the soil was not determined 
fer the reason that the soil was excessively wet, the water table be¬ 
ing at times within a few inches of the surface, and in parts of the 
plot, seldom more than three feet six inches below it, while in 
the highest portion of the plot it was only six feet from the surface 
at its lowest stage. One would think that, under such conditions, 
irrigation would not be needed ; that the sub-irrigation would be 
sufficient. We did not find this to be the case. The explanation 
probably lay in the fact that the root system accommodated its de¬ 
velopment to the conditions obtaining during the earlier and 
greater portion of the season, and when the water table fell the 
surface soil, owing largely to its unfavorable mechanical condition, 
dried out rapidly to a greater depth than a soil in good mechanical 
