94 
EDITORIAL OBSERVATION'S. 
reference to the analysis of sterile soil, we find that our crops will not now 
grow in the absence of these chemical salts; and, further, the analysis of 
fertile soil, proves they will grow when those same salts are present in 
an available form. A correct analysis of healthy, well-matured plants 
grown on any soil shows their invariable presence, and in the same kind 
of plants in nearly uniform proportions. The blood and tissues of animals 
hold in combination the same salts; without them the tissues could not 
exist, therefore they are essential to the well-being of the animal world. 
The animal derives his food from the vegetable, and with it the necessary 
chemical salts; hence we may, from the above facts, assume that the 
vegetable world could not exist, without the presence of the salts of lime, 
potash, &c. If, then, such are really the facts, it must follow that, as 
every ton of vegetable produces extracts and carries from the soil many 
pounds weight of chemical salts, that soil must be poorer by exactly the 
amount removed. 
We have, in this, the answer which chemical science gives to the 
practical question—How is it that repeated cropping, without manuring, 
impoverishes, and ultimately exhausts, our land? Thus, as crop after 
crop is carried off the land, the proportion of available chemical salts^ 
remaining in the soil, is gradually reduced, until a state approaching 
sterility is reached.” 
Mr. Jekyll then proceeds to show how different crops 
exhaust the soil, and the importance of a rotation of crops. 
“One kind of crop requires a heavy amount of soluble silica, while 
some other crop requires little or none of that compound. By taking a 
crop not requiring silica, time is given for its accumulation in the soil. 
Some plants rob the land of its nitrogen, others increase it. Some gain 
their support from the surface-soil, while others strike deep into the 
sub-soil, and draw from it a rich store of mineral wealth, which can be 
returned to the land as manure, to supply those which feed in surface- 
soil only. One class of agricultural plants requires for their well-being 
an excess of silica ; a second an excess of the salts of lime and magnesia; 
while a third will not flourish without an extra amount of the salts of 
the alkalies. Thus, by alternating the several kinds of crops, land is 
maintained in a productive condition for a greater length of time at less 
cost. But while this is clear, is it not equally and unmistakably evident 
that land must ultimately be more entirely exhausted by this system^ 
unless all manurial ingredients are added in the same proportion as that 
in wdiich they are removed by the different crops ? Yes ! to maintain 
land in its original fertility, every manurial element or compound— 
nitrogen, phosphorus, lime, &c.,—removed in a crop, must be restored 
in some form. Every sack of corn, pound of beef, mutton, or bone, truss 
of hay or straw, carried off the farm, reduces the productive capabilities 
of that land by exactly the amount of the nitrogen, phosphorus, potash? 
