406 



NEW ENGLAND FARMER. 



to the class in which I have put them, while oth- 

 ers seem, hy the very large quantities of sulphuric 

 acid and lime contained in them, to be peculiarly 

 plaster crops. AVith regard to all or nearly all of 

 them, I believe that the results of experience ac- 

 cord with the conclusion to which I am led by an 

 inspection of their elements ; — that they are es- 

 sentially benefited by the application of plaster. 



3. From 80 to 100 lbs. of plaster are often named 

 as a suitable quantity to apply per acre. If this 

 quantity were doubled, and then increased still 

 more in favor of those crops, which contain very 

 large quantities of the elements of plaster, there 

 would seem to me to be more wisdom in the pre- 

 scription, though I believe Liebig has shown, and 

 experience has confirmed, that something like 100 

 lbs. per acre is a suitable dressing for pasture 

 lands. It should in no case be regarded as a sub 

 stitute for manure. If the cattle did not manure 

 their own pasture, it would be in vain to plaster 

 it. So far from its taking the place of ordinary 

 manure, it is true that the more manure is put up- 

 on land, the more plaster may be used advanta 

 geously. As an animal cannot thrive on water, 

 as a substitute for food, but will drink about in 

 proportion as he feeds heartily ; so the land will 

 not be satisfied with plaster alone, but will repay 

 the owner for putting it on, about in proportion as 

 it is well provided for in other respects. Hence I 

 apprehend that no rule but that of common sense, 

 pretty well informed, can decide how much plas- 

 ter should be applied in any given case. 



4. As regards the manner of applying plaster. 

 It has by many been thought best to sow it in the 

 spring, in a damp atmosphere, that it may adhere 

 as much as possible to the stalks and leaves of the 

 young plant. This opinion seems to be founded 

 on the belief that its virtues are absorbed by the 

 leaves, which I believe to be erroneops. Too much 

 importance seems to have been attached to the ap- 

 plication of plaster to the moistened leaves of 

 plants. It may be well to apply it thus on pas- 

 tures and on mowings, not to be otherways man- 

 ured the same year, as it will be less liable to be 

 blown away by the wind ; but when its applica- 

 tion is to be made on tillage or on mow lands, that 

 are to receive other manure the same year, it seems 

 most reasonable to believe that it should be com- 

 posted with the manure, for the double purpose of 

 retaining its nutritious gases, and then at the pro- 

 per time of feeding the plants on its own elements. 



Having arrived at the conclusion that plaster is 

 beneficial on nearly all lands, if kept otherwise in 

 good condition ; that it is especially useful for 

 those crops which contain much of its elements, 

 and less so to others ; that the quantity is rather 

 to be decided by a consideration of the crop to be 

 raised, the amount of manure used with it, and 

 the known susceptibility of the soil to be benefit- 

 ed by plaster, than by any fixed rules, varying 

 from one to two or three hundred pounds per acre ; 

 and that it may well be applied to the young 

 plants in a moistened state on pastures and on 

 mowings not to be manured the same year, but 

 in other cases may better be composted with the 

 manure and with that incorporated irrto the soil, 

 I come now to inquire into the philosophy of its 

 action — how it operates on the air, the soil and 

 the crop? Here, fortunately, we have opinions 

 enough, but unfortunately they differ widely. 



Messrs, Girardin and Breuil, authors of an elab- 



orate treatise on agriculture, say :-^"It has been 

 said, and many farmers yetjuelieve, that the good 

 effects of plaster are due to its gathering moisture 

 from the air and hastening, by means of its lime, 

 the decomposing of organic matter in the soil. — 

 But these opinions," they add, "are altogether 

 erroneous, since this salt possesses neither of these 

 properties." 



Now, for the naked fact, that plaster, in its un- 

 changed state, as it enters the soil, possesses 

 neither the property of attracting moisture, nor 

 of decomposition of organic matter into available 

 food for plants ; the authority of these very able 

 writers is undoubtedly above suspicion. But in 

 its transformations in the soil, it may, and, I be- 

 lieve, does possess these properties in a high degree. 



It is well known that one of its constituents, 

 sulphuric acid, attracts moisture. Many a rogue- 

 ish dealer knows full well that in order to have his 

 carboy of sulphuric acid hold out like the widow's 

 cruise, he has only to leave the stopper out. Al- 

 though this acid, when combined with lime in the 

 form of plaster, may not possess the property of 

 attracting moisture, yet on its separation from the 

 lime it may, and probably does rejoin this, its orig- 

 inal property — may exercise it. in its transition 

 state, and retain it in its new combinations. 



Lime also, though not decomposing organic mat- 

 ter, while combined in the form of plaster, may 

 repossess itself, when let loose from that combina- 

 tion, of its original property of hastening the de- 

 cay of all that it touches. Who does not know 

 that the sill of a building, if embedded in lime mor- 

 tar, will soon rot 1 and that lime greatly hastens 

 the decomposition of organic matter in a compost 

 heap 1 If this, then, is a well known property of 

 lime, when not combined with sulphuric acid, may 

 it not resume this property at once on being dis- 

 charged from that combination 1 May it not ex- 

 ercise it on the organic matter of the soil, while 

 in transition at least, if not in its new combina- 

 tions 1 



The popular belief is, in this case, founded in 

 truth. You cannot make an observing farmer be- 

 lieve, but that plaster attracts moisture, and that 

 the lime it contains hastens the conversion of dead 

 matter in the soil into living organizations. This 

 is the popular belief. It is deduced from long ob- 

 servation. Many a farmer has adopted it, not 

 because he has heard of it, but because he has seen 

 it. Plaster, by means of its lime, prepares food 

 for plants out of inert matter ; and, by means of 

 its acid, it gathers moisture from the air and from 

 deep in the subsoil, and retains it for the use of 

 plants. Upon this last point, Messrs. Girardin and 

 Breuil themselves help us on, for in another part 

 of their very able work they tell us that plastered 

 lands will stand a drought much better than un- 

 plastered. Why is this, unless plaster attracts 

 and holds moisture 1 



Liebig believes that the good effect of plaster 

 consists entirely in its fixing the ammonia in the 

 soil and in rain water, so as to prevent its escape. 

 He supposes that the carbonate of ammonia in the 

 soil and in falling rain undergoes a double decom- 

 position with the plaster, by which carbonate of 

 ammonia and sulphate of lime become sulphate of 

 ammonia and carbonate of lime. In this, there 

 can hardly be a doubt, he is correct ; but in limit- 

 ing the good effect of plaster to the one office of 

 fixing the ammonia, he must be, as nearly all ag- 





