188 



NEW ENGLAND FAB/MER, 



Jnn. 2, 1829. 



Fron llie New York Farmer. 



ON USE OF GYPSUM IN AGRICULTURE. 



Sir — The extensive apjilication of Plaster of 

 Paris ill the interior of this state, to the pur- 

 poses of husbandry, induces nie to liazard a few 

 Remarks upon the causes of its fertility, and the 

 soils and crops to which it may be advanta- 

 geously applied. I perceive that many of our 

 farmers, aitliough slow to adopt this or any other 

 itinovation upon old habits, now that they liave 

 become satisfied of the benefit of plaster in some 

 Cases, seem to infer that it is useful in all, and 

 thus apply it without " rhyme or reason." The 

 consequence, I fear, will be to bring it into dis- 

 repute and lead to its rejection in cases where 

 its utility is unquestionable. 



The most common opinion is, that this sub- 

 stance benefits crops by drawing moisture from 

 the atmosphere. This theory proves too much : 

 for if it has so strong an affinity for moisture, 

 it will attract it from the soil as well as i'rom the 

 atmosphere ; and thus rob the plant, instead of 

 increasing their supply, of this essential agent 

 of vegetable developement. But it has been 

 proved that gypsum absorbs moisture far less 

 powerfully than putresciblc manures, or even 

 common soils, and retains it a shorter time. 

 Johnson has given us, in his essay on the use of 

 salt in agriculture, tables exhibiting the absorb- 

 ent and retentive powers of dilTerenl substances. 

 I subjoin an extract in proof of my position : — 

 "" Horse dung evaporated previously jfcrts. 

 to dryness, at a temperature of 100°, 

 absorbed, during an exposure of 

 three hours to air saturated with 

 moisture at (32°, 



o 

 o 



•a 



145 



Putrified tan bark, under like cir- 

 cumstances, (G6°,) 145 

 Unputrified, do 115 

 Cow dung do ISO 

 Pig do do . 120 

 Sheep do do 31 

 Refuse Salt (G3°) 49 

 Burnt Clay, 29 

 The richest soil (in one hour) 23 

 Lime, (part carbonate) 11 

 Gypsum, 9 

 Pig dung, evaporated to dryness, at 

 a temperature of 106° (the heat of a 

 meridian sun at midsummer) and 

 then moistened with six parts of 

 water, required for being reduced to 

 to dryness again, at the above tern- ruin. 

 perature, 135 

 Horse dung, under similar circum- 

 stances, 90 

 Common Salt, 75 

 Rich Soil, 32 

 Poor Soil (silicious,) 25 

 Gypsum, 18 

 Thus it appears, that the absorbent power of 

 horse dung is sixteen times greater than that of 

 gypsum, and its retaining power seven times 

 greater. Let us not lose siglit of another im- 

 portant fact which these experiments suggest, 

 viz : That the power of a soil for absorbing and 

 retaining moisture, and of course of resisting 

 drought, is in the ratio of the dung and vegeta- 

 ble matter which it contains — rich soil suffering 

 least, and poor soil most in dry weather. — 

 Ploughing and hoeing frequently tend very 

 much to increase, or rather to bring into full 



operation, these qualities of soils Vor ab.sotbing 

 and retaining moisture. 



After water has been expelled from plaster of 

 paris by burning or heating, it tlien again ah- 1 

 sorbs it powerfully — and not only absorbs, but 

 solidifies it. It is by this process that it is fit- 

 ted for cornices, busts, &c. 



Another agency which has been ascribed to 

 plaster in the process of vegetation, is that of ac- 

 celerating putrefaction in the soil — of rendering 

 inert vegetable matter soluble, and thus increas- 

 ing the supply of vegetable food. The experi- 

 ments of Sir H. Davy disprove this theory, and 

 show that gypsum rather retards than increases 

 animal and vegetable putrifaction. 



Some, supposing that plants are gifted with 

 sensation, contend, that gypsum acts as a con- 

 diment to the vegetable, as spices do to the an- 

 imal system, and benefits by stimulating their 

 absorbent and assimilating organs. I am not 

 phisiologist enough to discuss this point, and 

 will therefore barely observe, that if this is 

 so, all plants are not equally sensitive ; for many 

 are certainly not affected by this stimulus. 



Others again have maintained, that plaster 

 owes its utility to the sulphuric acid (oil of vit-l 

 riol) which it contains; and of course that a 

 decomposition or separation of parts, takes ))lace | 

 ill the soil. Sulphuric acid has been applied,! 

 blended with different parts of water, without 

 seeming to confirm this theory. But a suf- , 

 ficient objection is found in the fact, that Sjp- 

 sum is detected in the clovers and other plants, 

 showing that no decomposition has taken place, 

 and that the sulphuric acid, remaining chem- 

 ically combined with its base, could not liavc 

 acted separately. ! 



Sir H. Davy, I think, has suggested the true 

 cause of the fertility in gypsum : That it forms 

 as necessary a constituent of some plants, as a few ! 

 drops of peppermint do to a mint sling ; and that 

 when the soil does not contain it, in the small 

 proportion needed, its application is necessary 

 for their complete developement and pp-fection 

 — and that it is only useful to sneh crops as yield 

 it on anedijsis, and on soils loherc it is defieicnt. 

 Of the plants which contain gypsum, Sir H. 

 Davy has enumerated the clovers, hizern, ^anfoin '; 

 and .some other grasses; in which he believes 

 it may exist to the amount of three or foui bush- 

 els on an acre of these plants. The turnip crop 

 yields it in small quantities ; and if this theory 

 is correct, Indian corn and potatoes will ifTord 

 it, as it evidently benefits these crops. He adds, 

 that gypsum is nut talce.n up in corn crops, such ! 

 as wheat, rye, barley, &,c. A course of experi- 

 ments during ten years, lias satisfied me that 

 these crops are not benefited, directly, by its 

 application, but often indirectly, by increasing 

 the growth of other vegetables, which ultimately 

 enrich tlie soil. 



The soils which plaster inost benefits, are the 

 poor lean sands and sand loams ; and its effects 

 diminish in proportion as these become more rich, 

 adhesive, or wet. The dung of cattle contains 

 gypsum ; so does peat or bog earth. To lands 

 often dunged, its effects are consequently less 

 perceptible. That it does not prove efficacious 

 upon wet lands may bo accounted for by tlieir 

 generally abounding in bog soil, and not usually 

 producing plants which contain gypsum. 



As to the time and manner of applying piaister, 

 different opinions prevail. It cannot enter ih.e 



mouths of plants until it is dissolved, or become 

 soluble. To effect this, 500 times its weight of 

 water is found to be requisite. This would seem 

 to indicate that it should be sown early on grass 

 lands. My practice has been to sow in March, 

 or early in April, and if practicable, upon a light 

 snow. When sown late, and a cry summer en- 

 sues, its benefits are frequently not perceptible, 

 probably from the circumstance of its not having 

 been dissolved. I have followed the example 

 of two great pioneers in the improvement of 

 Amcrioan husbandry, the late Judge Peters and 

 John Taylor, in sowing it for Indian corn and - 

 potatoes before the last ploughing. I consider 

 the benefit in this method more certain and the 

 labor less, than in that of strewing it on the hills 

 of the growing crop. 



The experience of practical men seems to 

 have fixed the proper quantity at from one to 

 two bushels the acre. 



Plaster appears partially to have lost its effi- 

 cacy in sonic parts of Pennsylvania, where it has 

 been longest and most successfully used. It ia 

 said, to adopt the common language, that the 

 soil iias become tired of it. I suspect too much 

 reliance has been placed upon it ; and that it 

 has been used as a substitute rather than as an 

 auxiliary, for old fashioned barnyard dung. 

 There is another way of accounting for its ap- 

 parent failure. Has not the soil become tired of 

 the plants which it aids, and which may have 

 exhausted it of some other constituent 1 In the 

 Norfolk system of alternate husbandry, it was 

 long ago ascertained that clover could not be 

 sown to advantage oftener than every second 

 course, or once in eight or ten years, and other 

 grasses were consequently alternated with it. 

 The practice in Pennsylvania has been, I believe, 

 to continue sowing clover every four or five years. 



The preceding view of the subject and my 

 personal experience, induce me to offer the fol- 

 lowing rules for the consideration of the farmer: 



1. That plaster may be applied to pasture and 

 meadow lands, not absolutely wet, with strong 

 probability of profit — as it undoubtedly forms a 

 constitueit of many of the grasses, increases 

 their vigor, and thickens the soil. 



2. That it may be applied, with equal prospect 

 of success, to the maize and potato crops, atid I 

 think, to legumes, such as peas, beans, &,c. 

 These being sown, as good husbandry implies, 

 upon lands naturally free Irom surface water, or 

 rendered so by draining. 



3. That its benefits are greatest upon sands, 

 gravels, and light loams; and that these benefits 

 diminish in proportion as the soil becomes ricii, 

 either naturally or by the application of dung. 



4. That plaster can never become a substitute 

 for dung, but may be rendered a valuable auxil- 

 iary — benefiting some crops directly, and all 

 remotely, by increasing the volume of vegetable 

 matter, which ultimately becomes the food of 

 plants. 



5. That fioni one to two bushels per acre is 

 a sufficient annual dressing for lands. 



6. That u|)on grass it is most profitably sown 

 early, that the vernal rains may tender it soluble; 



■and upon tilled crops before the last ploughing, 

 that th.e moisture in the soil may perform this 



lofBce in .season, in both cases, to benefit the 

 summer's growth. 



j And, finally, That its use can be best regu- 



jlatcd by the farmer himself carefully noting its 



