130 BULLETIN OF THE BUSSEY INSTITUTION. 
when an abundance of each of the necessary fertilizers is at hand, 
that the “‘normal crop,” that is to say, the best possible crop, is ob- 
tained. By attending to all these particulars Hellriegel has suc- 
ceeded in growing, year after year, upon a tolerably large scale, 
examples of the several grain crops much larger, healthier, and more 
perfect in every respect, than have ever been met with in field prac- 
tice. He has been able, moreover, to produce at will plants of deter- 
minate size and weight by varying the conditions aforesaid, though 
the supply of food was unchanged, and to obtain repeatedly the same 
results when operating under like conditions. 
Applying these truths to the results obtained upon the experi- 
mental field of the Bussey Institution, it is plain that this field lacks 
depth of soil, and, above all, that it lacks water. In respect to these 
two conditions, the field, like thousands of others in New England, 
* 
has a certain natural but limited capacity to profit by the application of 
manure. It is useless to apply much manure to such land, unless the 
season should happen to be specially favorable. 
The results of the three years’ course of experiments show conclu- 
sively that, under the conditions which now obtain, the land is totally 
unfit for any system of “ high farming.” On the contrary, in order 
to be farmed with profit, it must necessarily be given over to some 
system of low farming, in which the expenditures for labor, tillage, 
and fertilizers shall be small, and the crops proportionally light. It 
is plain that the land cannot put to profitable use more than a certain 
small proportion of fertilizing matters ; and for that very reason it 
can at the best only produce mediocre crops. The land is not “strong” 
enough naturally to justify the application of large amounts of ma- 
nure. It cannot give to the manure that support and assistance that 
is needed, in order that the fertilizing constituents of the manure 
may be used with advantage, i. e. 1t cannot supply the conditions 
necessary for the successful growth of crops. In one word, the land 
lacks moisture. As has been stated already, on page 80, the surface- 
soil lies some fifty or sixty feet above the level of the ground-water. 
The layer of loam in which the plants grow is thin, and the bed of 
gravel beneath the loam is deep and coarse and open; so that the 
soil quickly becomes dry after rain, and is therefore, in our climate, 
constantly exposed to terms of drought. It would be impossible, 
economically speaking, to deepen such a soil. There is, in fact, but 
