FIELD EXPERIMENTS WITH FERTILIZERS. 163 
considered a sufficient weight of ears to make one bushel of dry 
shelled corn. In these experiments an average of 81 pounds was 
required for the good corn. 
SOIL TEST EXPERIMENTS. 
The plan of experiments for soil tests consists in applying, on 
parallel plots of land, fertilizers containing nitrogen, phosphoric 
acid and potash, singly, two by two, and all three together. The 
fertilizing materials were in all cases supplied by the Station in 
standard commercial forms, such as nitrate of soda, dissolved 
bone-black, and muriate of potash. In all of the experiments 
here described, the cost of the fertilizer is estimated from the 
retail selling prices of the materials, plus $2 per ton for mixing 
and freight. 
In most of the experiments a number of plots were added to 
the regular soil test. The object of these plots was to study the 
question of the most profitable mixture for use on particular 
soils. 
On the following pages, the comparative yields of the experi- 
ments discussed are shown by means of diagrams. The fertili- 
zers and the weights are given at the left of’the diagram. The 
length of the lines represent the comparative yields per acre 
from the different plots, and the figures given in the last column 
show the actual yields per acre. 
At the close of this article will be found a series of tabular 
statements, giving the results in detail. In all cases, the yield 
of shelled corn per acre is reported on the basis of 11 per cent. 
' water, and the stover on the basis of field weights. 
EXPERIMEN POGY Eke CEAUSS, 
The field upon which this experiment was located had been in 
grass for quite a period of years and was considerably “run 
down” by constant cropping without manures. One end of 
plots I and K extended onto ground that had been planted to 
potatoes the year before, and this may account in part for the 
small yields on those plots. The soil is a medium heavy loam 
with a gravelly clay subsoil. From the diagram it will be seen 
that the plots to which phosphoric acid (from dissolved bone- 
black) was applied, gave better yields than those where no 
phosphoric acid was used. This is in accord with many other 
experiments on similar soils. 
