The true Cause why Clover and St. Foin do not succeed so well after their own respective Species, or that of each other, as Corn, _&c._ can, is, that they take great Part of their Nourishment from below the Plough’s Reach, so as that under Earth cannot be tilled deep enough, but the upper Part may be tilled deep enough for the horizontal Roots of Corn, _&c._ towards which, the Rotting of the Clover and St. Foin Roots, when cut off by the Plough, do not a little contribute[213]; And there’s no doubt but that, if the under Earth could be as well tilled for the Tap-roots, as the upper Earth is for the horizontal, the Tap-roots would succeed one another as well as the horizontal would succeed them, or those of their own Species, or as the Tap-roots do the horizontal. [213] That the Rotting of vegetable Roots in the Ground doth ferment therein, and improve it for horizontal-rooted Plants, I am convinced by an Accident; _viz._ My Man had plowed off the Earth close to the Rows in a Field of extraordinary large Turneps designed for Seed. This Earth was neglected to be thrown back to the Rows, until a severe Frost in the Winter came, and killed the Turneps; upon which, in the Spring, the Field was sown with Barley upon the Level, with only _once_ plowing, and that cross-ways of the Rows. The Turneps had stood so wide asunder, that the Spot whereon each had rotted, appeared like the Spot whereon an Horse had urined in till’d Ground, and was of a deeper Colour, and much higher, than the Barley that grew round those Spots; and yet none of it was poor. As the Roots of Clover, and St. Foin, are very much less; yet the greater Number rotting in plowed Ground must be of great Use to a following Crop of Corn. I will here relate Two Examples of this in St. Foin: The one is, That a Field of Twenty-five Acres drilled with St. Foin, except Three Acres in the Middle of it, which was, at the same time, sown with Hop-Clover; after Eight Years the whole Field was plowed up by a Tenant, and sown with Corn: The St. Foin had been mowed yearly, as the Hop-Clover was not mowed at all, but fed by Horses teddered (or staked) thereon the First and Second Years; and after that had nothing on it but poor natural Grass. The whole Field was managed alike, when plowed up; but the Three Acres produced visibly worse Crops of Corn than the rest all round it, which had produced St. Foin.