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My purpose tins afternoon in making the few remarks that I have to make is to 
state broadly what my view is of some of these principles by means of which soil 
fertility may be conserved and increased. In the first place, we must have some idea 
of what fertility is. My idea of fertility is the ability of a soil under given condi- 
tions to produce a crop. We all understand that a soil alone, without *he environment 
in which it lives, can not produce a crop. The soil may he very good at the North 
Pole, but the crops are very meager because the other conditions of the environment 
are not good. Therefore, the first step in order to study the comparative fertility of 
any soils is to bring them under the same conditions; in other words, the environ- 
ment must be the same. But given the required environment, that soil is fertile 
which will produce a good crop, and that soil is infertile which produces a poor crop. 
That is my idea of soil fertility — the ability of the soil to produce a crop. I shall 
not now discuss the factors which produce this ability. 
In the experiments and studies made in this direction we have departed some- 
what from the ordinary course of the two forms of experiments which have been 
described. Mr. Ewell, one of my former assistants, wrote some years ago an article 
for the Yearbook, in which he tried to show that every farm should be an experi- 
ment station and every farmer an experimenter. When a man sends to me a specimen 
of soil and writes, "Please analyze this soil and tell me what crops I can grow on 
it," I send him word, "Ask your soil itself what you can grow on it; by asking your 
question directly of the soil, you can get a better answer than in any other way.'' 
I believe, therefore, that if we could obtain some comparative notion of the fer- 
tility of different soils peculiar to the United States when brought under the same 
conditions we might throw some light on the problems of soil fertility, its conserva- 
tion and increase. So we have brought to Washington soils from a numl>er of our 
States. These soils were, I believe, with one or two exceptions, secured from the 
agricultural experiment stations. We also brought here from England, through the 
courtesy of Sir Henry Gilbert, some of the celebrated soils of Rothamsted. After 
collecting these we had only one varying element as affecting comparative soil fer- 
tility, and that was the soil itself. These soils were all treated in exactly the same 
way — exposed to same temperatures, the same degree of light — receiving the same 
treatment in every respect. The product thus obtained was an accurate measure of 
their fertility under those conditions. The elementary conditions of crop culture 
have been already well described, so I shall take no time in going over them now. 
We had considerable trouble in getting the best form of pots in which to grow 
experimental crops. I made personal observations of the various pot experiments 
carried on in this and other countries in order to learn as much as possible from the 
various methods pursued. We adopted from different ones those features which 
seemed best suited to our purposes and thus finally obtained a method of conduct- 
ing our experiments. These experiments have now been continued for nine years, 
and the results are being prepared for publication. 
We fully appreciate what has been said here by previous speakers on this subject — 
that in order to have value such experiments must be continued for a long period of 
time and with a systematic purpose. For this reason some experiments, in them- 
selves interesting, have not the full value which attaches to those which have been 
continued through a number of seasons. 
I have here some photographs of these pots representing the crops produced by 
different soils in the same year under the same conditions. These soils, as I have 
said, are mostly from the United States. Without going into other particulars, I 
may say that there is shown a difference in the appearance of the same crops on dif- 
ferent soils, but with absolutely the same environment. A mere glance shows that 
the relative fertility of these soils differs very widely. Here [indicating] we find the 
yield almost nothing, there we find a very rich crop, and between these extremes 
there exists every grade of yield. 
In tins way we put the direct question to the soil, "Are you a fertile soil? We 
give you the conditions under which you can show what you are." This is the 
answer which these soils have given. These results show that the soils themselves 
have inherently different fertilizing principles; that they are different in their charac- 
teristics, and in most cases have different crop-producing capacities. 
Now, there is another question which we ask of these soils — "How rapidly under 
these conditions do you lose your fertility? ' ' Here are a few photographs illustrating 
the answers which the soils give to this question. We have hundreds of these photo- 
graphs; I have simply picked out a few. Here are answers to that question running 
over a term of four years, showing the results in the case of the same soil, the same 
crop, and the same conditions at different seasons. These soils had not previously 
been under cultivation. There [indicating] you see a diminishing fertility; but the 
diminution is mostly in the first year in this particular experiment. As you see, the 
