160 BULLETIN OF THE BUSSEY INSTITUTION. 
by our farmers are singularly unlike those which prevail upon the 
European farms that are most frequently described in works upon 
agriculture. For example, we have never in this country had any- 
thing to compare with that incessant returning of straw to the land 
which for a century or more was an article of faith in most of the 
best farming lands of Europe.* But by means of that practice the 
soil of many regions must have received a supply of potash that may 
yet endure for generations. There would be cause for surprise on ~ 
most New England farms if nitrate of soda applied as a fertilizer 
should produce in a succession of normal seasons as good an effect, 
pound for pound, as nitrate of potash. Yet field experiments in 
Europe have not infrequently indicated such a result. 
The practice of clearing land, whether of trees or bushes, by burn- 
ing, which is so common in many districts, can hardly fail to hasten 
the process of exhaustion, inasmuch as some portions of the ashes are ~ 
commonly washed into brooks and rivers by our heavy showers of rain, 
and because the first crops grown upon the burnt land are liable to 
take up and carry away a larger proportion of potash than the plants 
have any real need of, or than they would naturally take if the food 
were a little less accessible. 
It is not impossible that the generality of the rocks of New Eng- 
land, from which the soil was formed, may contain less potash than 
those of more favored lands. This is a question that I mean to 
investigate.t But from what has been said already, it will be seen 
that there is no need of falling back upon a supposition such as this 
so long as there are well-established facts at hand by which the pres- 
ent lack of potash can be explained. 
As regards the original poverty of our soils, the manner in which 
many of them have been formed, through the decomposition of the 
superficial layers of the great beds of loose stones, sand, and gravel 
with which the region is covered, cannot have been favorable to the 
production of a high degree of fertility. Besides the impoverishing 
effects produced by the mere leaching with rain-water of soils thus 
* For remarks on the forms of compact between landlords and tenants, with 
respect to the retention of straw, see the works of William Marshall, passim. Com- 
pare Loudon’s Encyclopxdia of Agriculture; Article, Restrictive Covenants with 
Tenants at Will, under Rents of Leases. See also Stoeckhardt’s Chemische Feld- 
predigten, I. 133, Leipzig, 1856. 
t See note on p, 161. 
