BULLETIN OF THE BUSSEY INSTITUTION. 115 
It is to be observed that although the barley and the bean crops of 
1872 are very light, owing in part, no doubt, to the bad season as well 
as to the exhausted condition of the land, the results obtained with 
them are, on the whole, excellent. These results are not only per- 
fectly coherent and comparable among themselves, as were those of 
1871, but they are actually better than the latter, in so far as the 
barley crops of 1872 were all safely secured and weighed. No sus- 
picion or uncertainty attaches to any of them, such as the depreda- 
tions of rats imparted to the crops of 1871. 
The results obtained on Sections A and AA are not comparable 
with those of the remaining sections, since, as has already been stated 
on page 86, the soil of A and AA is much better than that of the re- 
mainder of the experimental field. But it is plain from the other 
results that the land needs potash rather than phosphoric acid or 
nitrogen. The addition of potassic manures to the soil manifestly 
enables the crops to make use of a certain store of phosphoric acid 
and nitrogen that the land contains. It is clearly shown, moreover, 
that the amount of available potash in the land must be very small, 
since neither the phosphatic manures nor the nitrogenous manures by 
themselves, nor mixtures of the two, such as several of the so-called 
superphosphates are known to be, could enable the crops to get potash 
enough from the soil to keep them from starving, after the first year. 
Enough has been learned evidently from the experiments of 1871-72 
to justify the trial next year of mixtures of fertilizers such as shall be 
competent to supply the place of farm-yard manure upon the field in 
question. 
