^[469, 470, 471, 472] superphosphate of lime — ashes, 237 



already been referred to (T"436) ; and its effects, when used as a composting 

 material, are equally favorable. In many cases where the direct application of 

 gypsum to land is too expensive in proportion to the effects produced, it may be 

 made to pay exceedingly well, when used as a composting material — not only 

 (not in excessive quantity) with stable manure, but also with cottonseed, that 

 peculiarly southern fertilizer. It has been observed by agriculturists, that 

 decayed or " rotted'" cottonseed is much inferior in value as a manure, to the 

 same material when applied in the fresh state. The odor evolved by cottonseed 

 when decaying, loaves little doubt as to the cause of this deterioration : a great 

 deal of ammonia escapes into the air, leaving behind only the mineral ingredients 

 with some humus. These, in the absence of ammonia, act much more slowly, 

 and do not, therefore, produce so obvious an etl'ect upon one and the same crop, 

 as the fresh seed would have done while decaying in close contact with the 

 living plant. By a proper intermixture of the seed with some plaster, when 

 piled up for preservation as a manure, the ammonia may be retained, and the 

 effective value of the material essentially increased, 



469'. With respect to the use of lime or its carbonate in composting stable 

 manure, it is true that on chemical grounds its use has been discouraged, on 

 account of its property of so decomposing the salts of ammonia, as to allow the 

 latter substance to escape into the atmosphere. While this is strictly true of an 

 excess of lime, which effectually expels all the ammonia not combined with 

 humus, later experiments have shown that a certain moderate amount of lime 

 added to stable manure, furors the retention of these volatile ingredients, while 

 at the same time it har-tens essentially the decomposition of vegetable matter. 

 But in the case of our calcareous marls, the favorable action is exercised not 

 only by the marl on the stable manure, but also vice versa, by the decaying 

 manure on the alkaline ingre.lients of the marl, which are rendered more soluble, 

 and, therefore, more rapidly available to plants, by the combined action of 

 carbonic acid and ammonia. Thus these fertilizers mutually improve each other, 

 and a collateral advantage is gained by the deodorizing effects of the calcareous 

 material. The simultaneous addition of vegetable matters already decayed, 

 such as swamp or marsh muck, is particularly advantageous in this case, as it 

 will more effectually prevent the escape of ammonia ; even if in some parts of 

 the pile so much lime should have been accidently accumulated as to expel the 

 ammoniacal gas. 



470. Buperpltospate of Lime, wherever it can be had cheaply, is a highly 

 valuable addition to the manure pile, being most effectually retentive of ammonia ; 

 it may thus be made to subserve another purpose, besides supplying its 

 important nutritive ingredients to the soil (l[433). It ought not, however, to be 

 used conjointly with lime or calcareous marls, which would re-convert it into 

 bone-ash, from which it was originally manufactured. The chief advantage pos- 

 sessed by the superphospate over ground bones, is its greater solubility ; which 

 is lost when it is brought in contact with lime, either pure or as carbonate. 

 There is not, however, any objection to using it conjointly with gypsum or 

 plaster, or marls containing the same. 



471. Ashes. — Among the offal frequently available to American agriculturists, 

 and which may be profitably used as an addition to the manure pile, ashes of 

 all kinds, both leached and unleachcd, occupy a prominent place in point of 

 usefulness. In leached ashes, lime, magnesia and phosphoric acid, together with 

 a sm-dl amount of potash and soda still remaining, are the important ingredients ; 

 in the unleached material, a large amount of potash, and some soda, with chlorine 

 and sulphuric acid, are superadded to the above. The ashes of different woods 

 are of different value in this respect as well as in regard to soap-manufacture. 

 The ash of the Post Oak. for instance, is very poor in potash, while that of the 

 Black Jack Oak is selected for the purpose of soap-making, as is that of the pine 

 burrs. The agricultural value of these ashes is quite as variable. 



472. Fresh and Rotted Manure. — Tho question is frequently asked, whether 



