To Asher Robbins
Mont Pellier Augt 8th. 1818.
I have received your letter of July the 17th. and thank you for your friendly Criticism on the passage in the address to the Agricultural Society of Albemarle relating to the Theory of Tull.
Many Years had elapsed Since I read the Work of Tull, and I was of course guided by my recollection only aided by the references of others to it which had occasionally fallen in my way. I was very ready therefore to suppose that I had been betrayed into the misconception of his Theory which you intimated; and having not found it convenient to examine it throughout, Still think it possible that I may have done him injustice.
It would seem however from a glance at his Chapters1 on the food of plants—on Tillage, and on hoeing,2 that I was not wrong in considering it as a part of his theory that pulverized Earth is the food of plants; and that you have not Sufficiently adverted to his reason for leaving and tilling the intervals between the rows of drilled grain. The reason appears to be, not that the interval earth may be untaxed by the growing crop, and may be aided by the other elements for the Succeeding crop; but that it may enlarge the pasture for the growing crop, the roots of which, like those of Indian Corn & Tobo., spread and feed in the adjacent Soil when opened for them by the plough; the benefit to the Succeeding crop being found in the better tilth resulting from the preparatory Tillage.
It is indeed a question whether a fallow kept in a naked or pulverized State, does not lose more by exhalation than it gains by absorption. In hot climates & summer fallows at least, this is understood to be the case.
Notwithstanding the fundamental error which I have ascribed to Tull, I regard him as a great benefactor to the agricultural art. The error was of a nature to correct itself, it being impossible that continued pulveration without manure, should not be attended with diminishing crops; whilst the improved tillage, to which it led, could not fail to recommend itself by its good effects. His Book contains also many interesting facts, and judicious inferences from them.
I join you sincerely in the pleasure excited by the growing taste for agricultural improvements: and am justified by the Scope of the observations which your Letter contains, in numbering you among those most capable of promoting them. Be pleased to accept my respects and good wishes
FC (DLC). In John Payne Todd’s hand, except for JM’s complimentary close. In the top margin JM wrote: “To Asher Robins (Rh: Isld).”
1. JM interlined “at his Chapters” here.
2. Jethro Tull, The Horse-Hoeing Husbandry: or, An Essay on the Principles of Tillage and Vegetation.… (Dublin, 1733), 21–29, 44–53, 53–80.