portions, not material to the present inquirj', the 

 following substances, \\-hicli, according to Lie- 

 big, are supplied exclusively by the earth, ace- 

 tate of potash, phosphate of lime, silica, sulphate 

 of potash, phosphate of potash, chloride of pot- 

 assium, acetate of lime. These, as well as car- 

 bonic acid, ammonia and nitrogen, are hard 

 names, names new to most of us; w^e must 

 learn their import. Twenty-five j-ears ago we 

 knew not the meaning of piston and cylinder, 

 of steam-chest and satiet.y- valve. We all know 

 it now ; and as the application of steam to the 

 mechanical arts hasnotwTought a greater change 

 than the recent discoveries in Agriculture are 

 destsned to effect, we will have to shai-pen our 

 intellects once more and raise them to the level 

 of the times. Upon this,' however, I do not at 

 present insist, and if jou are disposed to be very 

 obstinate, take the mineral salts I have men- 

 tioned, as things which, being invariably found 

 in the cane azid never in the atmosphere, or in 

 rain water, should exist in the soil in a state fit 

 for assimilation by plants ; your lands must con- 

 tain in that state, potash, silica, lime, chlorine, 

 phosphoric acid, sulphuric acid and substances 

 yielding ammonia ; and should any of these be 

 wanting, they must be supplied by deep plow- 

 ing or by manure. 



As it is well known that cane flourishes equal- 

 ly well on all our alluvial lands, when they are 

 first brought into cultivation, we may assume 

 tliat all these lands once contained, in a state fit 

 for assimilation, the sub.stances necessary to its 

 growth. There is, therefore, no original deficien- 

 cy to supply, and wherever the cane has cea.scd 

 to grow and to rattoon as it once did, it is be- 

 cause those substances have been abstracted 

 from the soil by injudicious cropping. 



Knowing the mineral substances Avhich the 

 cane requires, chemists tell us that we might at 

 any time ascertain the deficiencies of our soil, 

 by having it analyzed. The suggestion is plau- 

 sible, but there is nothii^ in it ; we would be as 

 wise after the analysis as we were before. The 

 learned author already quoted shows that arable 

 lands are the result of the disintegration of rocks 

 during many thousand years : that this process 

 is ever going on at the surface of the earth, and 

 that many thousand years will elapse before it 

 is completed. By this process the alkalies and 

 salts which the earth contains, are gradually set 

 free and rendered fit for assimilation by plants; 

 and when all the substances thus set free have 

 been taken up, plants requiring them ■will cease 

 to grow in the soil where they are wanting, and 

 yet it will require thousands of years to effect a 

 complete disintegration. The quantity ab.stract- 

 ed by the cane in Louisiana, during a cultivation 

 in forty years, must be infinitely small in relation 

 to the quantity yet remaining, and accordingly 

 it is found, where land supposed to be exhaust- 

 ed has been analyzed, that it contains the same 

 elements as the fertile soils adjoining it, or found 

 beneath it, united in very nearly the same pro- 

 portions. It is not the precise quantity of the 

 different elements contained in our soil, which 

 it imports us to know, but that portion of them 

 which is disintegrated and fit for assimilation; 

 this, I apprehend, chemistry canuot tell us. 



If wc could evorv year provide a sufficiency 

 of mixed animal and bagassa manure for all the 

 land wc plant, it would be idle to inquire about 

 the deficiencies of the soil, sinee that manure 

 contains all the requisite substances. But, com- 

 pelled as v,e are by the .severities of the climate 

 to plant annually a large portion of our crops, 

 (284) 



we cannot save one-sixth of the quantity of ma- 

 nure required. This should be husbanded with 

 care and placed in rotation on the oldest lands ; 

 for the remainder, manure would have to be pur- 

 chased at an expense which would not be under 

 thirty dollars per acre, and the question natur- 

 ally presents itself^Is it necessaiy to incur that 

 expense and the extra labor to which it vs'ould 

 give rise ? Intelligent planters say that it is not, 

 and science justifies their opinion. If in the 

 lands that have beeii longest in cultivation, the 

 alkalies fit for assimilation are partially exhaust- 

 ed, it should be remembered that the plow has 

 seldom gone beyond the depth of six or seven 

 inches, and that below that depth is a virgin soil 

 in all respects similar to the original stirface soil 

 and deeper than the plow can ever penetrate. — 

 So that if a depth of six inches had yielded a 

 sufiiciency of disintegrated alkalies to cane 

 crops during thirty years, there is no rea.son why 

 the next six inches below should not do the 

 same, provided they can be brought to the sur- 

 face and kept in good tilth. With the thorough 

 drain system this presents no difficulty, and it 

 can be satisfactorily accomplished wdth the open 

 drains I have recommended. With those drains, 

 a depth of plowing of ten inches, when the 

 stubble is broken up for com, will give to the 

 land that cannot be manured, all the substances 

 which the cane requires from the earth but one; 

 it will not give a sufficiency of nitrogen. I 

 stated last year that nitrogen or ammonia could 

 only he supplied in large quantities by manure, 

 and I was not then aw are that any but animal 

 manure could effect that object. Further expe- 

 rience and observation have eati,sfied me that it is 

 supplied in great abundance by a process which 

 has long been followed without any clear con- 

 ceptions of its mode of action : I mean that of 

 covering the land with peas as early in the sum- 

 mer as the com crops will pennit. One of the 

 advantages of peas as a gTeen crop, is, that they 

 take from the land none of the alkalies which 

 the cane requires, while their powerful system 

 of roots has a tendency to accelerate the disinte- 

 gration of the soil. But their principal action 

 consi.sts in shading the land, thus preventing the 

 escape of ammonia which the rain water de- 

 po.sits in it, and hastening by shade and humidi- 

 ty the decay going on at the surface and the for- 

 mation of nitre which ever follows it in warm 

 climates. The leaves and seed of the pea are 

 richer in nitrogen than any other vegetable sub- 

 stance, and the result of their decay is the for- 

 mation of additional quantities of nitric acid. — 

 The nitre and nitric acid thus formed, as well as 

 the ammonia retained in the soil, yield to the 

 following crop of cane the nitrogen they con- 

 tain. The method now generally adopted of 

 plowing in the field trash, restores to the rattoons, 

 in a state fit for as.similation, most of the alkalies 

 which the plants took up in their growth ; and 

 should more ammonia be wanted, by setting fire 

 to the field trash after a rain, the top part of it is 

 converted into charcoal, which has the power of 

 absorbing ninety times its volume of ammonia. 

 To facilitate this operation, cane ought not to be 

 planted ^less than six feet apart. What pre- 

 cedes, and with it such fi-equent movings of the 

 soil as perpetually keep the young plants in an 

 atmosphere of carbonic acid, is the method pur- 

 sued in Loui.siana by all successful planters, and 

 the only material improvements I would suggest 

 to them are those of tliorough draining and sub- 

 soil-plowing. 

 There are, however, cheap mineral manures 



