18 



NEW ENGLAND FARMER. 



For the New England Farmer. 

 POTATOES AND THE ROT AGAIN. 



BY A. G. COMINGS. 



When I wrote my last article on this subject for 

 the Farmer, it was my intention to make that the 

 last which I would furnish upon that subject. But 

 as the editor has taken the liberty to place my 

 name at the head of the article, I find myself stand- 

 ing out before the world in the unenviable position 

 of a new theorist ; in opposition to the multitude 

 of respectable writers who have agreed in the opin- 

 ion that " the cause of the potato rot is atmos- 

 pheric." This is, for me, an unpleasant position; 

 because, firstly, if I am constrained to differ from 

 my friends, I prefer to hold the most modest and 

 retired position with respect to them, until the 

 reasons for my position are fully before them ; and 

 secondly, because I am not in a situation to spend 

 that amount of time in investigating such subjects, 

 and in writing for the press, that I could wish to 

 have for that purpose, if I must stand out before 

 the public in such an attitude. However, what is 

 past is past, and now for the work before me. 



The editor inquires, firstly, " Did not the potato 

 grow with perfect soundness on coal-pit grounds 

 twenty years ago ?" They grew with soundness 

 every where they were planted twenty years ago ; 

 but not equally good in flavor ; being on some 

 ground like the sound portion of a crop now, where 

 many are diseased. And the farmers said of such, 

 " These potatoes are soggy, and not fit to eat." — 

 Such potatoes were produced then on such grounds 

 as they rot, badly on now, if my memory serves me 

 in a right manner. 



Second in uiry of the editor, " Does it not grow 

 well now, on new land, where a thick mass of dry 

 grass and roots are turned under, which would be 

 the materials to give out carbonic acid in large 

 quantities? " This question contains with it an 

 affirmation, which is, that, " such materials give 

 out large quantities of carbonic acid." They give 

 out a quantity of the acid, as they are decomposed ; 

 but, unaccompanied by any stimulant, such as 

 ashes or things of the kind, only a small quantity, 

 when we compare the amount with that given oft 

 from a heavy dressing of manure. There is not 

 much carbon in a thick mat of tender grass, and no 

 very great amount in the roots. Besides this, 

 these vegetable remains are decomposed very grad- 

 ually, and they lay the ground open very much to 

 " atmospheric" influences, which, in my opinion, 

 are highly beneficial to the healthy growth of the 

 potato. But take such a piece of ground where 

 there is a great supply of vegetable remains, years 

 old and yet undecomposed, there will be found 

 much carbon. Apply any stimulant to produce 

 rapid decomposition, and you may get a large 

 growth and a rotten crop. This is precisely the 

 state of the case with Mr. H., of Pelham, N. H., 

 whose statement is given in No. 40 of the (weekly) 

 Farmer. 



Third question — " Does it not grow far better 

 on such land, than on old land, though the old land 

 may have received no manure for years? 



In answer to this question, we will say, on the 

 •old land there will be less growth, if the vegeta- 

 ble remains are all decomposed and exhausted, or 

 if the soil is in such a state as to exclude atmos- 

 pheric influences. Nothing will grow without a 

 needed supply of the gases which enter into its 

 composition. The question is not whether car- 



bonic acid, in any quantity, more or less, is injuri- 

 ous to the potato? Not at all. It is well under- 

 stood that the potato will grow most rapidly in a 

 very rich and active soil, and that in such a soil, 

 during the warm and wet season, a very large 

 quantity of carbonic acid gas is generated. And 

 on all such ground, especially where the soil is 

 not very porous, the great crop is fearfully sickly. 

 The excess of carbonic acid, not its presence in any 

 quantity, is that to which we attribute the prevail- 

 ing disease. 



The decomposition of old sward takes place so 

 gradually that very little fermentation is apparent, 

 especially where the ground is not unusually rich 

 and moist. There, a piece of newly cut iron will 

 rust moderately, or, which is the same, it will be- 

 come oxidized but moderately. On highly manured, 

 or very rich old ground, where there is a great 

 abundance of carbonaceous earth, there much fer- 

 mentation will take place, iron will rapidly coat 

 with oxide, and there look out for potato rot. (The 

 oxidation of iron is more rapid, because of the 

 large quantity of oxygen gas which is combined 

 with carbon to form carbonic acid.) 



THEORY OF ATMOSPHERIC INFLUENCES. 



Unpleasant as it may be to dispute the correct- 

 ness of the idea that the potato rot is caused by 

 some poison which floats in the air, we must beg 

 pardon of our friends for taking the liberty to dis- 

 sent from them, and proceed to the discussion of 

 the subject. 



The editor expresses a common idea, and one 

 with which I fully agree, when he says, " We 

 have no doubt that manuring in the hill always has 

 a tendency to induce the rot." 



When I shall be convinced that manuring in the 

 hill is an operation performed in the air, not in the 

 soil, then it will be easier for me to believe that 

 the cause of potatoes being more commonly blighted 

 under such circumstances is atmospheric. Two 

 square rods, side by side, may be planted with the 

 potato. One rod shall be manured in the hill with 

 strong manure, and the other not. There will be 

 a great difference in the chances of a sound crop. 

 But does not the same atmospheie float over both ? 

 Whence comes the disease, then ? From the air ? 

 No. It originates in the soil. 



The case of Mr. H., of Pelham, N. IL, comes 

 up. Two strips of land, side by side, are planted. 

 Was the difference between them a difference in 

 the atmosphere? Did not precisely the same at- 

 mosphere cover thera both? Certainly it was, that 

 the difference was in the soil, not in the atmos- 

 phere. If the addition of manure to one part, un- 

 der circumstances calculated to prevent fermenta- 

 tion at the time the potato is most easily affected, 

 was subject to another influence which moderated 

 its' decomposition, it would not induce disease. — 

 Those circumstances might be in the action of the 

 plaster, (sulphate of lime,) in the manure lying 

 upon the surface of the ground, or in the dryness 

 of the weather. When I can believe that the dif- 

 ference of condition of the two pieces was an at- 

 mospheric difference, I can more easily believe 

 that the cause of the disease was in the atmosphere. 



It has become a matter of surprise to me, that 

 almost every man will tell what kinds of soil are 

 most liable to give diseased potatoes, and what 

 kinds of soil are most likely to produce sound ones, 

 and then turn round and Jell us that the cause of 



