1862. 



NEW ENGLAND FARMER. 



389 



to be informed. From two to four bushels of 

 plaster is the quantity usually applied to the acre. 



We have referred to the diiference existing 

 ameng scientific men regarding the operation of 

 plaster, and we give the opinions of three of the 

 most celebrated doctors. 



Sir Humphrey Davy held the opinion that the 

 influence of gypsum on clover, sainfoin, rye grass, 

 and other plants of this character, is due to their 

 containing naturally a large proportion of sulphate 

 of lime. He examined the ashes of these plants, 

 and found that they afforded considerable quanti- 

 ties of gypsum, which substance, he thought, 

 might probably be intimately combined as a ne- 

 cessary part of their woody fibre. He believed 

 that Arhere gypsum failed to produce a good re- 

 sult, it would be found that the soil naturally con- 

 tained so much of the salt, that its artificial sup- 

 ply was unnecessary. 



Prof. Liebig's opinions are thus stated in the 

 Ci/cloprcdia of Agriculture : Prof. L. explains 

 the action of gypsum upon grasses, by a reference 

 to its well known power of converting the volatile 

 carbonate of ammonia into the more fixed sul- 

 phate of the same base. When sulphate of lime 

 is mixed with a solution of carbonate of ammo- 

 iiia, all ammoniacal smell soon disappears. By a 

 mutual interchange of elements, carbonate of lime 

 and sulphate of ammonia are formed, and the lat- 

 ter salt, not being volatile at ordinary tempera- 

 tures, remains without loss in the liquid. 



Prof. Liebig further states that "a part only of 

 the carbonate of ammonia, conveyed by rain to 

 the soil, is received by plants ; because a certain 

 quantity of it is volatilized with the vapor of wa- 

 ter. Only that portion of it can be assimilated 

 which enters deeply into the soil, or which is con- 

 veyed directly to the leaves by dew, or is absorbed 

 from the air along with the carbonic acid." 



Now it is to the power, possessed by gypsum, 

 of converting the carbonate of ammonia into the 

 sulphate of the same base, and thus preventing 

 its volatilization when it has once come in contact 

 with the soil, that Prof. Liebig partly attributes 

 the action of gypsum as manure. We say partly, 

 because he expressly says that "the evident influ- 

 ence of gypsum upon the growth of grasses, the 

 striking fertility and luxuriance of a meadow on 

 which it is strewed, depends, in some degree, upon 

 its fixing in the soil the ammonia of the atmos- 

 phere, which would otherwise be volatilized with 

 the water which evaporates." And in other parts 

 of his well known work on Agricultural Chemis- 

 try he shows in what way plants derive the sul- 

 phur, required for the production of their albu- 

 minous constituents, either directly or indirectly, 

 from sulphate of lime. Prof. Liebig, then, con- 

 siders that gypsum acts as a source per se of food 

 to plants, but still more as a means of presenting 

 ammonia to them in greater abundance — in other 

 words, that in applying gypsum to a soil, we are 

 in fact Hianuring with an ammoniacal salt. 



M. Boussingault, who advocates the third theo- 

 ry which we have to notice, has taken occasion, 

 in enunciating his views, to criticise with great 

 ability both of the preceding explanations of the 

 action of gypsum. 



In reference to Prof. Liebig's theory, M. Bous- 

 gingault shows that to double the crop of clover, 

 which a di'essing of gypsum is well known to do, 

 the whole of the rain falling during the life of the 



plant must have contained l-17000th of its weight 

 of carbonate of ammonia ; and that even allow- 

 nig that this proportion of ammonia could exist 

 in rain water, great corrections would require to 

 be made for the quantity of rain which either does 

 not penetrate the soil at all, or is returned to the 

 atmosphere without passing through the plants. 



Admitting, however, for the sake of argument, 

 that the effect of gypsum upon clover, lucerne, 

 sainfoin, (Src, is really attributable, to its fixing the 

 ammonia of the atmosphere and of rain, M. Bous- 

 singault justly asks why it is that it does no good 

 whatever to natural pastures, and still less to root 

 or corn crops. Theoretically it would be expect- 

 ed that a proportionate advantage should be de- 

 rived by all crops from the ammonia so obtained, 

 and it is a matter of notoriety that ammoniacal 

 salts largely increase the produce, of natural grass- 

 es, and form an excellent manure for wheat. These 

 facts seem perfectly irreconcilable with the expla- 

 nation offered by Prof. Liebig for the action of 

 gypsum in agriculture. — Rural Neio-Yorkcr. 



For the New England Farmer. 

 CULTURE OF THE ONION, 



Yesterday I visited the grounds of P. L. Os- 

 born, an industrious laborer of this place, and 

 found him busily engaged, hoeing in his field of 

 half an acre of the potato onion. Never before 

 having particularly noticed the culture of this va- 

 riety of the onion, I was induced to inquire as to 

 the advantages of its culture. The first and most 

 prominent advantage is, that it is less liable to be 

 injur-ed by the onion maggot, or destroyer, that 

 has for several years nearly annihilated our onion 

 crop. Mr. Osborn's field appeared vigorous and 

 promising ; and he said he hoped to obtain from 

 it several hundred bushels. Several of his neigh- 

 bors are pursuing the same course of culture. 

 When such men thus illustrate their faith by their 

 works there is the best of reason to hope their ef- 

 forts will be successful. The boys in the Lane 

 about Wilsoii's Corner, are not often observed 

 chasing game, in a swamp, where none is to found. 

 If they cannot overcome the maggot in one way, 

 they will get around it in another. They rise ear- 

 ly, and work late, and eat the bread of careful- 

 ness. They do not wear kid gloves, except on 

 Sundays, and then only when going to Quaker 

 meeting. P. 



South Banvers, Jiily 19, 1862. 



HOW DEEP SHOULD DRAINS BE DUG? 



This is a question upon which there always has 

 been and perhaps always wiU be a difference of 

 opinion. The depth required must depend on the 

 kind of soil, for if the soil is a hard one, on top of 

 a hard, gravely one, I do not find that there is 

 much advantage in going far into the hard pan. 

 If, on the other hand, the subsoil is loose and 

 more easily dug, there is an advantage to be de- 

 rived from going deeper. 



My rule is, to guage the di'ains by their distance 

 apart. Let the depth be one-seventh of their dis- 

 tance asunder, and it will secure a thorough drain- 

 age. If the subsoil is hard, and the digging ex- 

 pensive, then do not sink the drains so deep, but 

 place them closer together, but hold on to the 

 above rule. 



