24 HINTS ON SOILS AND FERTILIZERS 
Let us now examine the above plot. We find 
that each plot in the diagram is 4 rods long, 
and one rod wide, with a width of one rod be¬ 
tween each plot on which there is no fertilizer. 
This blank space of one rod wide is left be¬ 
tween each of these plots to serve as a check. 
By this arrangement, the results of each plot 
can be compared very easily to the untreated 
ground, or blank space. It also aids in pre¬ 
venting the fertilizer from one plot from get¬ 
ting over into the other plot, as the width of 
one rod is usually sufficient to overcome any 
defect in the distribution of the fertilizer. 
In plot one, we will apply 5 pounds of nitrate 
of soda. This is a readily available form of 
nitrogen. In plot number two, we will apply 
ten pounds of acid phosphate, a quickly avail¬ 
able form of the phosphorus element. Then in 
our third plot we will apply 5 pounds of potas¬ 
sium sulphate, a good source of potash. Finally, 
in our fourth plot, we will add the three fer¬ 
tilizers that were applied separately in the 
other three plots and apply them all in this 
plot, and in the same amount that they were 
applied in each of the other plots separately. 
Hence we are now in a position to note during 
the growing season, and especially at the ma¬ 
turity of the crop raised, just what element or 
elements are lacking in this particular piece of 
ground, and also an idea of how bad the ele¬ 
ment or elements are needed. It might be 
added at this time, that different crops do not 
respond alike to these tests, as we have pre¬ 
viously noted that corn and cotton, for in- 
