I do not hold that the remarkably rich soils I have instanced needed fertilizing when first plowed; I will presume that they did not. Yet, having never yet succeeded in manuring a corn-field so high that a few loads more would not (I judge) have increased the crop, I doubt whether even the richest Illinois bottoms would not yield more Corn, year by year, if reenforced with the contents of a good barn-yard. And, when the first heavy crop of Corn has been taken from a field, that field--no matter how deep and fertile its soil--is less rich in corn-forming elements than it was before. Just so sure as that there is no depletion or shrinkage when nothing is taken from nothing, so sure is it that something cannot be taken from something without diminishing its capacity to yield something at the next call. Rotation of crops is an excellent plan; for one may flourish on that which another has rejected; but this does not overbear Nature's inflexible exaction of so much for so much. Hence, if there ever was a field so rich that nothing could be added that would increase its productive capacity, the first exacting crop thereafter taken from it diminished that capacity, and rendered a fresh application of some fertilizer desirable. Years ago, a Western man exhibited at our Farmers' Club a specimen of the soil of his region which was justly deemed very rich, taken from a field whereon Corn had been repeatedly grown without apparent exhaustion. A chemical analysis had been made of it, which was submitted with the soil. It was claimed that nothing could improve its capacity for producing the great Illinois staple. Prof. Mapes dissented from this conclusion. "This soil," said he, "while very rich in nearly every element which enters into the composition of Corn, gives barely a trace of Chlorine, the base of Salt. Hence, if five bushels per acre of Salt be applied to that field, and it does not thereupon yield five bushels more per annum of Corn, I will agree to eat the field." Many men fertilize their poor lands only, supposing that the better can do without. I judge that to be a mistake. My rule would be to plant the poorest with such choice trees as thrive without manure, and pile the fertilizers upon the better. It seems to me plain that of two fields, one of which has a soil containing nine-tenths of the elements of the desired crop, while the other shows but one to three-tenths, it is a more hopeful and less thankless task to enrich the former than the latter. If you are required to supply to a field nearly everything that your proposed crop will withdraw from it, I do not see where the profit comes in; but if you are required to supply but a tenth, because the soil as you found it stood ready to contribute the remaining nine-tenths, it seems to me that the margin for profit is here decidedly the greater.