188G.] 



FARMERS' REGISTER. 



215 



Ihat the magnesian mixture in the soil may in- 

 deed, uiuler certain condilions yet unknown, not 

 he injurious to li'rtility: hut there still reumin mul- 

 liplieil (acts, and the results of ohservations, of 

 wliich our whole plain presents us with a new and 

 <rroat example, that nuuiy magnesian soils are un- 

 productive. 



Eut how docs magnesia occasion harrcnncss in 

 a soil? This prohlem is doubtless ofdiliicult solu- 

 tion, but very important, since it seems probable 

 that if we knew the causes which render magtie- 

 sia unproductive, it would pei'haps be possible to 

 remedy them; we shall attempt to point out some 

 data which perhaps may indicate the course. 



And first we will remark that the m;ignesian 

 mixture takes from the soil all its characteristics ol' 

 calcareous soil, deprives it of all the advantages 

 which always accompany the unadulterated mix- 

 ture of the calcareous principle, and gives it a cha- 

 racter peculiar to itself, which clistinguishcs it whe- 

 ther by its mode of acting on vegetation, or by the 

 vegetables which it spontaneously produces, to 

 the exclusion of those produced by the calcareous 

 soil. 



Still farther, it would seem, that magnesia takes 

 from the carbonate of lime the property which 

 eminently distinguishes lime and all its com- i 

 l)ounds; that of rendering hitmas soluhle, and that it 

 tends on the contrary to render hiinim insoluble, 

 in proportion as it is accumulated hi the soil by 

 cultivation. In fact, the great proportion of inso- 

 luble humus, which the analyses have found in the 

 soil which composes three-fourths of the cultivated 

 plain, although a part might have been owing lo 

 an accident, could not proceed irom spontaneous 

 vegetation in this soil which is almost always un- 

 der the plough, and which produces few plants. 

 It proceeds then from cultivation: but cultivation 

 does not furnish insoluble humus; the humus of the 

 manures, then, have passed into this state in the 

 soil. Now, it is not the lime, the action of which 

 consists in rendering humus soluble, that can have 

 produced a contraiy etfecl; neither is it the silex 

 nor alumine to Avhich it is attributable; it must 

 therefore be charged to the magnesia alone, ami 

 to this circumstance we may ascribe the unproduc- 

 tiveness of magnesian soils, in which manures, in- 

 stead of benefiting the plants cultivated on the 

 soil, pass into the state of insoluble humus. 



The carbonate of magnesia has, besides, the 

 property of retaining more water than all the other 

 earthy combinations. According to the experi- 

 ments of Schubler of IlofTwyl, it receives and re- 

 tains four and a half times its weight. It may 

 be possible that it communicates to the soil in 

 which it is found, the property of retaining a quan- 

 tity of water, which at first ^vould be injurious to 

 vegetation. This would explain the cause of the 

 rot among sheep on this soil; but this water, after 

 having injured vegetation, would not continue 

 in the soil, for it suffers much from drought in the 

 spring. 



In this state of affairs, and in a question so im- 

 portant, on which doubts are accumulated, and 

 facts and opinions are arrayed in opposition, it is a 

 great and noble agricultural problem, that the pro- 

 prietor has proposed for himself to subdue (his re- 

 bellious soil and force it to yield good crops; we 

 shall see hercaller that this object has been, in a 

 great measure, obtained. 



IV. After this long diacussion on the magne- 



sian soil of the plain, we come to the soil of the 

 plateau: this kind of soil composes a great part of 

 the arrondissemcnt ol"Montargis, especially in the 

 south and south-east portion; it covers besides al- 

 most the whole extent of the arrondissenient of 

 Gien on this side and beyond the Loire. This 

 soil has received the name oi' terre de Solagne; the 

 only differences which characterize the parts slop- 

 ing towards the Seine and those which slope to 

 the Loire, are the chalk flints in the basin of the 

 Seine and the fragments of different varieties of 

 silicious rocks in the portion of the plateau which 

 slopes to the Loire. 



The soil ot'lheplatcau of Barres offersevery where 

 a pure clayey sand, which contains in great quan- 

 tity the chalk flints ol' the basin of the Seine, and 

 varies little. Yet it is dry or wet according to the 

 sub-soil on which it rests; when it is based inmie- 

 diately on the calcareous rock of the plain it is dry; 

 and it becomes wet when its sub-soil is tlie reddish 

 silicio-argilaceous stratum which does not allow 

 the water to pass tliroiigh, and consequently pre- 

 serves the moisture of the surface. 



This soil, compared to that of the plain, is not of 

 difficult cultivation. Rye, potatoes, and buckwheat, 

 grow well enough upon it; with manures, artificial 

 meadows succeed; and trees of every kind, leafy 

 (feuillus) nnd resinous, shoot up vigorously. On 

 the whole, this portion of soil which touches the 

 calcareous /j/a/eait, on which besides it rests, is su- 

 perior in quality to the parts of the plateau which 

 are more distant from it. It is even of more easy 

 cultivation, and oilers especially more resources 

 than the magnesian soil; nevertheless, it contains' 

 no calcareous parts, heath, broom, and wild sorrel, 

 which every calcareous mixture puts to flight, 

 are met with on this soil in all parts of the 20(> 

 arpents of it which are lef^t untillcd. 



V. I'he rest of the soil, under the pliugh, oF 

 which the property in composed, presents a gentle 

 slope, on which the owner's house is situated. 

 This slope forms the passage from the plateau to 

 the plain, going along the valley; it offers 150 ar- 

 pents of pretty good soil, suitable for all produc- 

 tions, for wheat, artificial grasses, trees, and espe- 

 cially for oaks; this soil is due to a mixture of the 

 soil ol the plateau and of the plain, but the mixture 

 is not uniform. 



VI. Lastly, it remains for us to speak of the 

 little valley which separates the two parts of the 

 property. 



This narrow valley receives the waters of the 

 plain and the plateau; it contains a great number 

 of springs, which are doubtless the filtered waters 

 of the two plateaux which have no visible springs. 

 It is very remarkable that the springs come almost 

 all of them fi'om the side of the calcareous plain, 

 the silicio-arffilaceous plateau with its impermea- 

 ble sub-soil, has scarcely admitted any filtration, 

 so its side furnishes few or no springs in the valley. 



A great part of the bottom of the basin is 

 marshy, requires draining and seems to us very 

 susceptible of being drained; one part is in pretty 

 good pasture, another in tolerable meadows, and 

 tlie rest in marsh, which is mown for litter. 



The calcareous rock shows It-self from time to 

 time at the bottom of the valley. The upper stra- 

 tum o^ the soil, belongs rather to the magnesian 

 soil of the plain than to the silicious soil of the 

 plateau. It is firm in all the parts which the inte- 

 rior waters have not diluted. Works judiciously 



