35S 



THE SOUTHERN PLANTER. 



decay of organic matter in the soil, is unhesi- 

 tatingly asserted by Professor Johnston— even 

 when the decomposing substance is purely car- 

 bonaceous. [Ed. auar. Jour. Ag., 1849 p. 584.] 

 Jt is unnecessary to give the abstruse laws ot 

 chemistry upon which these results rest; but 

 to assume the conclusion as correct, that when 

 decomposition of organic matter occurs in 

 contact with air, a small and variable propor- 

 tion of ammonia and nitric acid are produced 

 at the expense of the free nitrogen of the at- 

 mosphere. [Ibid.; see also Boussingault, 312; 

 Mulder, as quoted in Edinb'g Jour. Ag., 1847, 

 p 47 1 In this connection he also states, "in 

 proportion as the presence of lime promotes 

 this decay of vegetable and other organic mat- 

 ter in the soil, in the same proportion does it 

 promote the production of ammonia and nitric 

 acid at the expense of the free nitrogen of the 

 atmosDhere; and this may be regarded as one 

 of the Valuable and constant purposes served 

 by the presence of calcareous matter in the 

 soil." And, "lime influences in an unknown 

 degree the nitrogen of the atmosphere to be- 

 come fixed in larger proportion in the soil, in 

 the form of nitric acid and ammonia than, 

 would otherwise be the case; and this it does, 

 both by the greater amount of decay or oxida- 

 tion, which it brings about in a given time, 

 and by the kinds of compounds, which, under 

 its influence, the organic matter is persuaded 

 to form. 



I have thought proper to impress upon the 

 Society the fact, that the decomposition of 

 vegetable substances may be as judiciously 

 conducted in the soil, or on its surface, as m 

 the farm-pen— and that there is really no gain 

 from the laborious process of hauling in straw 

 to be drenched with rain and partially fer- 

 mented, to be hauled out with great additional 

 weight and labor. Even unrotted pine leaves, 

 as raked up from the woods— though on acid 

 soils they produce injurious effects— on soils 

 which have been rendered calcareous, " pro- 

 duce only and always beneficial results; and 

 that is the best as well as the cheapest mode 

 of their application."— [Ruffin's Essay on Cal. 

 Manures, p. 72 ] These researches of dis- 

 tinguished chemists are in accordance with 

 ^observations of intelligent farmers; and I 

 know of nothing within the range of well con- 

 ducted experiments that contradict them. It 

 has been long known, that no benefit was de- 

 rived from ploughing under summer cow-pens: 

 it is explained by the fact that the absorbent 

 powers of the soil can retain the ammo- 

 nia and that further decomposition increases 

 it from the air. The observed effects of top- 

 dressing may receive the same solution; as 

 also the shallow covering of manures. The 

 striking effects produced by covering young 

 clover with straw, weeds or other vegetable 

 substances— producing results in the growth 

 and luxuriance of the clover far surpassing 

 the apparent fertility imparted by the cover- 

 ing—may be explained by the same reasoning. 

 Indeed, the ultimate products of decay and pu- 



trefaction, whether occurring in the farm-pen 

 or in the soil, are carbonic acid, water and am- 

 monia. [Liebig, 105.] Thequantityandquality 

 of the organic matter will be the measure of 

 fertility imparted to the soil in its ultimate de- 

 composition. The greatest return may not be 

 received in the first crop, but the maximum of 

 improvement to the land, and the most suc- 

 cessful cropping for a series of years will 

 follow. 



It may be proper also to state that the de- 

 composition of the straw, &c, furnishes a con- 

 stant supply of carbonic acid to the leaves 

 and roots of growing plants, which must not 

 be regarded as trivial or insignificant. For 

 four tons of perfectly dry vegetable matter 

 will yield nearly one-fourth as much carbonic 

 acid as exists in the whole atmosphere over an 

 acre of land. It is constantly rising through 

 their leaves and furnishing an additional sup- 

 ply of food. It also acts in combination with 

 water as a solvent upon the mineral ingredients 

 of the soil, and by this means furnishes an in- 

 creased supply of the inorganic elements of 

 food to plants. The power of water charged 

 with carbonic acid to dissolve the important 

 minerals was tested by the Professors Rogers, 

 late of our University. By their experiments, 

 the specimens digested in carbonic acid water 

 frequently furnished a sufficient amount of the 

 dissolved mineral to admit of quantitative an- 

 alysis — reaching in some instances from | to 

 1 per cent, of the whole mass. [Edinbg. Gluar. 

 Jour. 1847. J 



The other means of fixing the nitrogen of 

 the atmosphere is by a proper rotation of crops. 

 It appears to be a well established fact, that 

 certain plants possess the power of assimilat- 

 ing and fixing the nitrogen of the air, either 

 directly through their roots, or by inducing 

 the formation of a compound of nitrogen which 

 is appropriated. Among these plants the clo- 

 vers, peas, beans, and all pod bearing or legu- 

 minous plants, are the principal. [Boussin- 

 gault.] The more frequently they come into 

 the rotation, the greater will be the relative 

 assimilation of nitrogen, and the consequent 

 supply of ammonia to the soil. Direct analy- 

 sis has settled the fact that where those planis 

 come into the rotation, the amount of nitrogen 

 contained in the crops, greatly exceeds that 

 applied to the soil in the whole of the manures, 

 snowing an excess per acre, of from thirty to 

 one hundred pounds of nitrogen. [Boussin- 

 gault.] This valuable property of this class 

 of plants distinguishes them as the best ame- 

 liorating crops in any rotation. It is due to 

 that distinctive power of feeding upon the ni- 

 trogen of the atmosphere, and preparing it for 

 the food of the cereal, or other marketable 

 crops in the rotation. This class of plants 

 must not be regarded as the means of retain- 

 ing in the soil what it previously possessed ; 

 but as making a large addition to its fertility 

 through this power of supplying nitrogen; and 

 to this must be attributed one of the great be- 

 nefits derived from the usual field system, 



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