THE FERTILITY OF SOILS. 141 
is with worn-out soil, and partially covered roots 
naturally requiring a more substantial manure than 
what wovld suffice to ripen the young wood and 
increase crop upon the young tree. From this I 
infer that artificial manure mayin many instances be 
used alone with impunity and with success on young 
plantations for a few years, or as long as the soil it- 
self is not exhausted. 
“With regard to the method of application, the 
kind of manure used, the general features of the 
ground and appearance ef the trees will show at a 
glance to-any practical planter the best course he should 
pursue. The nearer the surface, so long as the man- 
ure is sufficiently covered to prevent waste and the 
effects of the sun’s heat, it will, I believe, show 
quicker results; but I should strongly oppose anything 
like surface manuring, as being impracticable and 
unsound in theory. it is more than prvbable that, 
after a little time, manuring in the centre of the 
square will become very general on young estates, 
especially as holing at the upper side of the tree has 
the effect of making the roots tend to one side, whereas 
holing in the centre of four trees prevents the cutting 
of large roots and tends to the free and longest growth 
ef the root.” , 
THE FERTILITY OF SOILS. FS 
in a recent letter to the New York Farmers’ Club, 
Professor 8. W. Johnson, of Yale College, says :— 
‘The labours of chemists to discover positively all 
the causes of the fertility of soils have not yet met 
with conclusive suecess. The mechanical structure of 
soil is of primary importance. Naked rock grows 
lichen ; the same rock crushed into coarse grains grows 
a much higher order ef vegetable; pulverized fine, 
the cereals grow in it. Geology, chemistry, botany, 
physiology, meteerology, mechanics, hydrodynamics, 
heat, light, and electricity are all intimately com- 
bined in the grand process of vegetation. There are 
sandy soils in our KHastern States which, without 
nanure, yield meagre crops of rye and buckwheat ; 
but there are sandy seils in Ohio which, without 
manure, yield on an average eighty bushels of Indian 
cern an acre, and have yielded it for twenty to fifty 
years in unbroken succession, the ingredients of these 
soils being, by chemical analysis, the same. At pre- 
sent no difference is known between them, except 
the coarseness of the particles—the first being coarse, 
while the Ohio sand is an exceedingly fine powder. 
The power of soils to attract and imbibe moisture 
