44 
Colorado Experiment Station 
present in the fo.rm of nitric nitrogen. It is for this reason that I 
have preferred to state the tixin^g power of this soil as found by 
laboratory experiments. 
We have not been able, up to the present, to follow the study 
of the bacteriology of this soil further than was given in Pa,rt I. 
The study of the composition of the plant, and the effects of 
the fertilizers, have been iDresented, together with a general state¬ 
ment of the weather conditions for the two seasons. 
One of the first, important questions in ou.r study, especially 
under our conditions, is: What is the effect of different amounts 
of wmter applied to the soil? Others have studied this question in 
relation to the production of dry matter, but not, so far as I know, 
as touching the composition of the plant. This question is impor¬ 
tant in our study, but is incidental to it, for this reason we have 
prosecuted it only so far as seemed advisable to determine its in¬ 
fluence in a general way. We found no differences in the amount of 
nitrogenous compounds in the plants that could be attributed to 
the varying amounts of water applied. 
This statement is based on two seyies of samples which have 
received 31 inches of water in all, 24 inches iyrigation and 6.77 
inches rainfall, compared with 16 series grown with 19 inches of 
of water, 12 inches irrigation and 6.77 inches rainfall. I am speak¬ 
ing of the plant at this time, but I shall p,resent the effect of dif¬ 
ferent quantities of water applied to the soil on the composition of 
the kernels, at another time. This question was presented in an¬ 
other form in 1915, when a series of light rains, amounting to about 
13 inches during the growing season, kept the plants wet a great 
portion of the time and further caused very heavy dews, so that the 
plants, not the soil, were thoroughly wet by application of water 
almost daily. The amount of water received by the crop in the two 
seasons was essentially the same, about 19 inches, but the effects 
which seem attributable to water, o.r more accurately stated, to the 
manner of its application in 1915, a,re very marked. For the pres¬ 
ent it may suffice to state that it caused the principal differences 
in the composition of the plants up to the end of July, at which pe¬ 
riod another factor, largely the result of this external moisture, 
began to play a still more important payt. This factor was the 
abundant development of rust. These conditions were unfortunate 
so far as the size of the crop was concerned, but fortunate for the 
purpose of our study, though we did not desiye to introduce these 
factors into our problem. The general effect was to suppress all 
forms of nitrogen present in the plant throughout its growing pe¬ 
riod, and the same was true of the ash constituents. It seems almost 
as though this externally applied water had actually caused a leach¬ 
ing out of the very substance of the plant. This does not seem so 
improbable, especially in regard to the ash constituents, when it is 
