230 AGRICULTURAL REPORT. [11444, 445 



of calcareous marls, containing other useful ingredients) would be quite super- 

 fluous and useless. It must be remembered, however, that the reverse is not 

 necessarily true, viz : that the light color of a soil is a sign of the absence of 

 lime ; it is so only when at the same time, a copious supply of vegetable matter 

 is present in the soil. 



In addition to the qualities just named, it has been observed that calcareous 

 soils are less subject, as a general, thing to injury by excess of wet, or drou.h, 

 than land otherwise similarly constituted, but poor in lime. This may be 

 referable, to some extent, to the favorable influence of lime on the production of 

 humus, which, as mentioned before, is a safeguard against both these causes of 

 injury. 



There are, however, over and above the points mentioned, a great many 

 special cases in which the application of lime to soils may serve as a correction, 

 or to fit it for special purposes of different kinds. Taking all this into consid- 

 eration, the importance to an agricultural State, of an abundant supply even of 

 pure lime in an available from, becomes obvious enough. 



444. Difference between Lime and Marls. — With reference to the large majority 

 of the marls of this State, the case assumes yet another aspect, and that of the 

 highest importance. They are not merely mixtures of carbonate of lime with 

 clay (silicate of alumina), but they contain, besides, considerable amounts of 

 most or all ifie other ingredients required by. plants, and foremost among these, 

 of Potash; also Soda, Magnes a, Phosphoric and Sulphuric Acids. When, 

 therefore, we apply these marls to land, we not only stimulate the latter, but we 

 add to its capital stock of fertility ; and in a great many cases, we can thus fully 

 replace all the drain of nutritive matter which the increased activity of vegeta- 

 tion may withdraw. We can thus, in fact, sustain the fertility of our soil 

 ■without resorting to any other means than mailing, and from time to time, 

 plowing down a green crop. For, knowing the composition of the crop 

 we have raised, and hence being able to calculate precisely how much of the 

 mineral nutriment of vegetables has been withdrawn from our field; knowing 

 also, the composition of the marl we may have at our command : we can return 

 to the soil all it has lost ; and if we do so conscientiously, the soil will improve 

 in the course of time, instead of deteriorating, as is commonly the case. It is 

 not to be understood, by this, that this replacement will be made perfectly by 

 adding simply the amounts of marl which would be calculated from the analysis 

 made, as corresponding to the loss sustained by the land in cropping ; for only 

 a portion of the ingredients obtained in analysis can be considered in an availa- 

 ble condition, and we must therefore add a large excess over the calculated 

 amount. Yet we are thus enabled to proportion our dressings, in a great degree,, 

 both to the quantity and quality of the ingredients withdrawn on one side, and 

 to be furnished on the other. 



445. Different Condition of Ingredients in Soils and Marls. — In comparing 

 the analyses of some of the rich soils analyzed with those of the marls, it will 

 be seen that the former contain more potash, for instance, than some of the latter, 

 which are nevertheless recommended as fertilizers. The question may then be 

 asked, why, if it be profitable to apply these marls, it would not be equally so 

 to employ those soils in a similar manner ? 



The reason is, that in most soils the greater part of the nutritive ingredients 

 are in a condition in which they are not immediately available to plants, and 

 only I ecome so by the long continued action of the atmosphere, or of stimulants ; 

 whereas the marls usually contain their potash, for instance, in the state of 

 greensand grains, which very readily give it up to the roots of plants. Or, in 

 the case of clay mails in which greensand is not demonstrably present, the case 

 is still the same as when we apply a strong dressing of lime to soils rich in 

 potash, etc. We thus render available a considerable amount of nutritive 

 ingredients, in the course of a few years (f 368, ff.), by the powerful action of 

 lime on the undecomposed minerals of the soil. If such is the effect of lime 



