I have been credibly inform’d, that on One Perch of Ground there has grown a Bushel of Corn, which is Twenty Quarters to an Acre. Mr. _Houghton_ relates Twenty-six, and even Thirty Quarters, of Wheat on One Acre. There have certainly grown Twelve Quarters of Barley to an Acre, throughout a whole Field: Therefore, unless a Crop exceed the least of these, or indeed the greatest of them (if the Relation be true), a Crop cannot fail for want of Room; for one Acre (be it of what Nature it will, as to the Soil of it) must have as much room for a Crop to grow on, as any other Acre. Then there was room for all Dr. _Woodward_’s Three Crops together, to produce as much as Three common Crops do. Yet all these together will scarce yield one Quarter of Corn, tho’ there is room, at least, for Twelve. The same _Air_ and _Sun_ that had Room to do their Office to Mr. _Houghton_’s Acre, why should they not have Room to do the same to Doctor _Woodward_’s Acre, when the Three Crops growing on it at once, through pretty good ones, might require less Room than Mr. _Houghton_’s Crop did? I perceive that those Authors, who explain _Vegetation_, by saying the Earth imbibes certain Qualities from the Air, and by specific Qualities, and the like, do also lay a great Stress upon the _perpendicular_ Growth of _Vegetables_; seeming to fansy there is little else necessary to a good Crop, but Room. Mr. _Bradley_, in his Arguments concerning the Value of an Hill, does implicitly say as much. But if they would but consider the Diameters of the Stems, with the Measure of the Surface of an Acre, they would be convinced, that many, even of Mr. _Houghton_’s Crops, might stand in a perpendicular Posture upon an Acre, and Room be left. One true Cause of a Crop’s failing, is want of a Quantity of Food to maintain the Quantity of Vegetables, which the Food should nourish. When the Quantity of Food which is sufficient for another Species (that requires less), but not for that which last grew, to grow again the next Year, then that other is beneficial to be planted after it. The Second true Cause is from the Constitution of Plants; some require more Food than others, and some are of a stronger Make, and better able to penetrate the Earth, and forage for themselves. Therefore Oats may succeed a Crop of Wheat on strong Land, with once plowing, when Barley will not; because Barley is not so well able to penetrate as Oats, or Beans, or Pease, are. So a Pear-tree may succeed a Plum-tree, when another Plum-tree cannot; because a Pear is a much stronger Tree, and grows to a much greater Bulk; so inclined to be a Giant, that ’tis hard to make it a Dwarf; and will penetrate and force its Way thro’ the untill’d Earth, where the other cannot; being of a weaker and less robust Constitution, not so well able to shift for itself.