BULLETIN OF THE BUSSEY INSTITUTION. 169 
is hard to believe that the practice of drenching rich land with 
dung, and with manures that are in some sort complete, can be truly 
philosophical so long as there are vast tracts of land all over the 
world still waiting to be tilled. It is undoubtedly true that, during 
the last twenty or thirty years, much intelligent action has been 
brought to bear upon the question how best to use all the available 
sources of plant-food, and that many European farmers now utilize 
the natural fertility of their land more fully than was formerly the 
case, notably by manuring with active nitrogen compounds and with 
superphosphate. But there would still seem to be room for improve- 
ment in that regard. It would be exceedingly interesting to learn 
how many European farmers have intelligently sought, in the light of 
Messrs. Lawes and Gilbert’s famous research,* to use up to the point 
of economic completeness any excessive store of either kind of plant- 
food that their land may have contained naturally, or which may have 
accumulated in the land through the application of straw and dung 
continued for long terms of years,,and to know with what measure of 
success the effort has been attended. 
It is evident that experiments made upon the fertile European 
soils, like many of the practices of the farmers who till them, can 
have but little direct application for the solution of problems that 
present themselves in New England. On examining the records of a 
large number of German experiments, I have been surprised to find 
how small a proportion of them were made upon really poor land. 
Some of them, indeed, as has just been indicated, have served merely 
to point out the danger of adopting too intense a system of cultiva- 
tion, inasmuch as neither nitrogenous, phosphatic, nor potassic ma- 
nures gave any increase over the abundant crops obtained from the 
plots that were left unmanured. In most of these cases the soils 
were doubtless in the same predicament as those squares of my own 
experiments that were heavily dressed with mixed fertilizers ; that is 
to say, they contained an excess of all kinds of plant-food over and 
above what the crops could make use of under the conditions to 
which the land was exposed. Many of the European experiments 
would undoubtedly have given more useful results, even as regards 
the land upon which they were made, if the fertility of the soil had 
* Report of Experiments on the Growth of Wheat for Twenty Years in Succes- 
sion, on the same Land, by J. B. Lawes and J. H. Gilbert, London, 1864. 
VOL. I. 2 
