208 



NEW ENGLAND FARMER. 



May 



HUMUS— LIME. 

 ,^/-o^ UMUS is vegetable matter in 



"^^^ ^■M^f'r^^'' * state of decomposition, 

 and supplies the source 

 whence plants principally 

 derive their food. The 

 power of enduing soils with 

 fertility is one of the most 

 important in the routine of 

 farming operations, and is 

 effected in a variety of ways ; 

 but the most economical and 

 efficacious method, perhaps, 

 is the turning in of green 

 crops. 



Wlien this method is adopted, the plants se- 

 lected should be such as are capacitated by na- 

 ture to derive the principal part of their sus- 

 tenance from the air, and which are therefore 

 the less likely to exhaust the soil of the limited 

 amount of humus contained in it during the 

 development of the growing crop. 



Up to the period of inflorescence, those 

 plants denominated aerial, or belonging to the 

 air, — and among which may be enumerated 

 bui'k wheat, peas, and the clovers, — draw but 

 slightly upon the resources of the soil ; the 

 economy of vegetation being such in regard to 

 them, that but a-comparatively slight degree 

 of aliment is required from this source. This 

 enables us to account for the well-known fact 

 that some crops, nearly deficient in productive 

 energy, often produce a large amount o( straw, 

 though they fail in maturing a crop of grain. 



When vegetables of an aerial character are 

 inhumed by being carefully turned under with 

 the plough, and embedded compactly in the 

 soil, th« vegetable tibre, or organized struc- 

 ture fjf the plant, is speedily resolved into hti- 

 vius ; the fermentive and putrefactive process 

 being accomplished with greater or lesser ra- 

 pidity according to the character of the atmos- 

 phere, and the condition of the soil, as regards 

 huuiidiry, at the time it is turned down. The 

 gaseous products of the mass, eliminated dur- 

 ing the process of fermentation, are eagerly 

 absorbed by the soil ; while the other products, 

 i. e., those of a solid character, if permitted 

 to remain undisturbed, are soon incorporated 

 and mixed with it; but should the soil be 

 again ploughed btfore the important process 

 of decomposition has been thoroughly effected, 

 — which is too frequently the case, especially 

 where a dry crop succeeds a green one, — 



much the larger portions of the gaseous, and 

 no inconsiderable portion of the solid products, 

 will inevitably be dissipated and lost to the 

 soil. 



In order to avoid this loss of valuable prin- 

 ciples, and render the application more imme- 

 diately appropriable by the growing crop, it 

 has been recommended to sow lime, from five 

 to twenty bushels per acre, before turning 

 down. The efficiency of this mineral is now 

 too generally well known to admit of any 

 question, and in no way, perhaps, is its appli- 

 cation more immediately beneficial than as an 

 accompaniment for green crops, when turned 

 in as a help for lands that are poor and light. 



Such soils frequently abound in acids. These 

 are sometimes native to the soil, and some- 

 times produced or added to it by the sub- 

 stances applied as manure. But whatever 

 may be their origin, they are speedily neutral- 

 ized by the use of lime. Ths fact is now well 

 understood that al^lants, grown for food, re- 

 quire lime for the perfection of their seeds. 

 Its free use, therefore, in agriculture is recom- 

 mended by Dana and Hitchcock. These 

 writers contemplate its action as threefold, 

 each distinct. 



1st. It is a neutralizer. Either in its cal- 

 cined state, or in the form of a carbonate, lime, 

 according to their authority, will combine with 

 any acid that may be present in the soil in a 

 free state. And they say : — 



"If the carbonate of lime is employed, the 

 carbonic acid which it contained is set free, 

 and becomes food for plants. 



"It is a decomposer. IMany of the metallic 

 oxides will be decomposed by lime, and their 

 components will form new combinations, or 

 be absorbed by plants." 



According to Dr. Dana's views of geine, the 

 soil may be affluent in geates, — or in other 

 words, geic acid will combine with earths and 

 metals and form salts not easily soluble, but 

 which lime will decompose and render soluble. 



It is a converter. "The great use of lime," 

 remarks Professor Hitchcock, "is as a con- 

 verter, turning solid, insoluble geine — nay, I 

 may go further — solid vegetable Jibre, into 

 solid vegetable food.'''' 



Calcareous earth, that is, chalkv, or limy, 

 is applied in one of three different forms, viz : 



As calcined, (burnt) lime, either in a slaked 

 or un^-laked state, as a carbonate of lime ; that 

 is, either pulverLied lime, shell marl, or claya 



