40 
Research Bulletin No. 3 
low point. Sixteen pots with maize plants from 3 to 4 feet high 
in the same greenhouse and only a few feet from the cylinders 
thruout the day remained uninjured but they had been liberally 
watered early in the morning of June 12. 
Xo whitewash was used on the windows of the greenhouse. 
As in the experiment of the preceding year, a close watch 
was kept for the development of any crevice between soil column 
and cylinder wall, and as soon as one appeared loose surface soil 
was at once worked down into it. Later, when the cylinders were 
opened, it was found that no crevices had extended below twelve 
inches, and all were full of surface soil. Accordingly there had 
been no opportunity for direct evaporation from the sides of the 
soil columns. In order to maintain a good mulch in some of the 
cylinders, it was necessary, on account of a portion of the orig- 
inal mulch having been worked down into these crevices, to add 
more dry surface soil, amounting to from 300 to 500 grams, the 
amounts being recorded at the time and included in the totals 
given in Tables 11, 13, 15, and 17. 
No soil crust formed below the mulch in the implanted 
cylinders but in all the others a very hard crust had developed 
by the end of the second month after planting. 
As soon as the plants in a cylinder died they were removed, 
the cylinder opened as soon as convenient and the moisture of 
the soil determined. The roots in the different foot sections of 
the subsoil were separated out, photographed, dried, and weighed. 
The experiments were much simpler in so far as the soils 
were concerned than those of the preceding year. Only semiarid 
soil, again from the H O Ranch, was used and this consisted of 
only three bulk lots, namely, the first 6 inches, the second 6 
inches, and a composite subsoil referred to hereafter as "H O 
Subsoil." The last was taken from the fourth, fifth, and sixth 
feet in an excavation made in the prairie field from which the 
soils used in 1908 and 1909 had been secured. After this sub- 
soil reached the Experiment Station it was thoroly mixed, while 
dry, by shoveling, passed thru an eighth-inch screen, and again 
mixed. This subsoil was not only representative of the subsoils 
of an important dry land area of the state but it was such that 
it could be placed in the cylinders so as to be very similar to 
the condition in which it occurs naturally. Extensive studies of 
this soil in pits and borings on the H O Ranch, as well as in va- 
rious other cylinder experiments, have shown that there is a very 
close resemblance between the condition of the soil, both in the 
wet and in the dry state, in cylinders and the condition of it in 
the field. 1 
*A fuller description of the properties of the "H O Subsoil" is given 
on p. 249 of the article by Alway and Clark, referred to on p. 28. 
