MARL. 



GOl 



smallest proportion of incrgaDic matter in the pro- 

 duction of plants. And since Liebig concedes 

 that until the leaves are formed, the plant de- 

 rives its carbonic acid from an artificial atmos- 

 phere senerated by the contact of humus in the 

 soil with the air. it would not be safe to denounce 

 this theory in the present state of science, as ab- 

 surd. It is admitted too on all sides that plants 

 do assimilate carbon from the atmosphere, and it 

 seems established thatammonia descends in rain 

 water. However true this may be, and though 

 Liebisf's theory ■was establi.'^hed as perfecth' so 

 in all its parts. I should think it most prudent to 

 hold on still to what experience and rational de- 

 duction have taught us of the influence of vese- 

 table mould on crops, in the hope tliat farther 

 discoveries might harmonize old facts and new 

 truths, especially as none of us would set about 

 improving the atmosphere, or desire to add more 

 carbonic acid or nitroiren to it, since any material 

 increase of these elements would render it fatal 

 to animal life. Indeed, no scientific discoveries 

 or force of logic can ever. I am convinced, for an | 

 instant shake your confidence or that of any I 

 practical farmer, in vegetable mould and com- 

 post manure ; or lead you to doubt that the 

 amount of your crop, if properly tilled under fair 1 

 seasons, depended in all other respects ■«-holly j 

 and solely on the quality of your land. Whether I 

 the soil furnishes 1 part or 99 parts in a hundred j 

 — you have too often seen plants on the same ! 

 acre subject to the same identical atmospheric ! 

 influences throughout, varj-iug Worn good to ; 

 worthless, accordins: to the soil, to question tlie ; 

 important fact that by improving your laud you ' 

 improve your crop in the same ratio precisely. ' 

 and that by exhaasiing it jou equally deteriorate i 

 the crop. i 



In fact, depth of soil, by -which we mean depth ! 

 of decaj-ed vegetable mould mixed with sand, j 

 clay, &c.. has been with you, as with all the ' 

 world heretofore, a criterion, and a never failing j 

 one. of the value of land, and so it ^^^ll forever | 

 continue to be, I venture to assert. If then, as I 

 I believe, and you will probably agree, plants . 

 derive their most important constituents of all I 

 kinds from the soil and from vesetable mould, the [ 

 value of lime in the soil is by no means limited ! 

 to its action on the mineral or inorganic consti- ' 

 tuents of it, but extends to the production also of • 

 those organic elements which preponderate so ; 

 immensely in all vegetation. ' 



But your inquiry- of me was in reference to ' 

 marl. I must therefore, remind you again that j 

 all \vhich has been said of lime is true of marl. ■ 

 If it is slower than lime in its early operations, ' 

 that is more than compensated by many advan- 

 tages which it possesses. This is becoming so 

 well understood that, wherever the same quan- 

 tity of lime can be placed on land as cheaply in 

 the tbrm of marl, it is rapidly superseding the ' 

 use of it in all other forms. Marl contains, be- 

 sides carbonate of lime, otlier valuable constitu- ; 

 ents. Its silex and alumina, though fine in qual- 

 ity, are not of much consequence, since they are ' 

 never thus applied in sufficient quantities to af- 

 fect the soil materially. But some marls — those 

 in Virginia, for instance — contain sometimes 

 sulphate of lime and the valuable green sand of ' 

 which I have spoken. As the sulphate of lime • 

 exists there in Eocene marl, it may be discov- 

 ered in our formation. 1 have .seen green sand 

 in specimens from several localities in this State. ' 

 A deposit of green sand, such as is found and | 

 used to an immense extent in Xew-Jersey, i 

 would be more valuable in your County than I 



the richest gold mine in the world. There is 

 none of it at Shell Bluff. ^ have already spoken 

 of phosphate of lime. In marl from Ashlev 

 River, in this State, which belongs to the same 

 formation as our marls, 5 per cent, of this phos- 

 phate has been discovered. From some crude 

 experiments of my own, I am inclined to believe 

 it exists in some of the marls at Shell Bluff, and 

 j probably in yours — to what extent I would not 

 I undertake to say. But .t per cent, of it would 

 I give you the equivalent of 9 bushels of ground 

 1 bone.s.in every hundred bushels of marl. Which 

 alone would be worth more than the whole cost 

 I of applying that quantity of marl, thon^'h the 

 ! expense of it might be five dollars. We can- 

 I not, however, expect to find it in such quantity 

 j in all the marls we use. Those will probably 

 I be richest in it in which are found remains of 

 I bones and teeth. In the shell marls on tlie 

 I Rhine, recent analysis has detected an important 

 I proportion of azote, derived, it is supposed, from 

 I animal matter. This is the most powerful, as 

 I you know, of all manures. There is every rea- 

 I son to believe that a scrutiny equally rigid would 

 disclose a valuable proportion of it in our shell 

 marls here. 

 1 The duration of marl in the soil is undoubt- 

 j edly greater than that of lime. The question of 

 I the duration of calcareous earth applied to lands 

 j is one of great importance itself, and about 

 I which yon will, no doubt, desire to be satisfied 

 before attempting to use it I have mentioned 

 already that the ancients regarded marl as pro- 

 ducing its efiects from 10 to SO years. Lord 

 Kames states an instance of their being observ- 

 able for 120 years, and Mr. Ruifin another of 60 

 years. Few or no records of such experiments 

 have been handed down from generation to gen- 

 eration. In diose countries where lime and 

 marl have been used most extensively and for the 

 longest period, it is impossible to say how long 

 the land produced before they were applied at 

 ail, in comparison with its production now. Of 

 late years, more accurate accounts have been 

 kept. The peculiar effects first observed to fol- 

 low the application of lime have been thought 

 to disappear or materially diminish at various 

 periods, reaching from 4 to 40 years, according 

 to the amount applied and other circumstances. 

 It is supposed by vrriters and farmers abroad 

 that about 3i bushels of it are consumed per an- 

 num by the crop, and that in general ilie influ- 

 ence of any quantity will cease in from V2 to 20 

 years. But these conclusions are not to be re- 

 lied on. It is certain that no crop will take off 

 so large an amount as 8 J bushels, and the loss 

 from other causes is altogether indefinite. — 

 While though, at the end of 20 years, tlie same 

 precise effects as at first may no longer be ob- 

 servable, it by no means follows that tliis may 

 not be owing to the want of proper application's 

 of other manures that would excite tlie lime 

 again to its original action. Mr. Ruffin thinks 

 that marl, once placed on land, will endure as 

 long as the clay and sand in it Though we 

 might not indulge fully in this belief, I am of 

 opinion that it wjU last for a period which may 

 be called indefinite, from its remoteness — par- 

 ticularly when crops are srrow n such as \ve cul- 

 tivate. Irish potatoes consume more lime than 

 any other crop, perhaps : nine tons, which are 

 sometimes erown upon an acre, though not with 

 us. ab^;tract about 266 lbs. or say 3^ bushels — but 

 260 lbs. are contained in the tops, which we 

 never take from the land. A thousand bushels 

 of turnips, tops and all, consume about 2 bushels 



