228 



THE FARMER'S MAGAZINE. 



INQUIRY RESPECTING THE QUANTITY OF NITRATES CON- 

 TAINED IN THE SOIL AND IN THE WATERS. 



[translated from the FRENCH OF THE "JOURNAL d'aGRICULTURE PRATICIUE."] 



In a former paper I endeavoured to demonstrate that 

 saltpetre acts directly upon the development of plants. 

 I mentioned the experiments made upon the employ- 

 ment of nitrate of soda of Peru in extensive farming, 

 and called to mind that nitrates had been detected, for a 

 great length of time, in arable lands possessed of a high 

 degree of fertility, by Bowles, Praust, and Einhoff, in 

 the waters of brooks, rivers, and springs ; in meteoric 

 waters by Bergmann and Berzelius ; and, more recently, 

 by the remarkable labours of Messrs. Bineau, Henri 

 St. Claire Deville, Brandes, Liebig, Bence Jones, and 

 Barral. 



In the researches I have had the honour to lay before 

 the Academy, I proposed to myself to extend the inves- 

 tigations of my predecessors, by determining what, at a 

 given moment, is the quantity of nitrates contained in a 

 hectare of arable land, a hectare of meadow, a hectare of 

 forest land, and a cubic metre of river and of spring- 

 water. 



The nitrates have been found in forty samples of 

 earth ; but, before presentin;; the result of these dis- 

 coveries, I must first make known the circumstance 

 which has induced me to undertake the work. 



I had had occasion to observe that the plants brought 

 from the kitchen-garden of the ancient monastery of 

 Liebfrauenberg contained considerable quantities of 

 nitrates. Beet-roots, which I had cultivated in 1854 at 

 the request of M. Peligot, contained also so large a 

 proportion, that it became nearly impossible to ex- 

 tract the sugar from them. 



Each year the kitchen-garden received in autumn a 

 heavy manuring with rotten stable-dung. The soil is 

 light, being a disintegration of the sandstone of the 

 Vosges, and other motley kinds. The water is not re- 

 tained in it, because the porosity of the earth descends to 

 a considerable depth. 



On the 9th of August, 1856, after fourteen days of 

 drought, accompanied with great heat, we took some 

 vegetable earth from a bed, and to one kilogramme of 

 that earth, dried in the sun, we applied the equivalent 

 of 0.211 grammes of nitrate of potash. The litre of dry 

 earth, weighing 1.500 kilos., we have 516.05 grs. of 

 nitrate to the cubic metre ; so that on the 9th of Au- 

 gust we might estimate the saltpetre contained in a hec- 

 tare of the kitchen-garden at 1.055 kilos., taking 0.33 

 inch as the mean depth of the vegetable mould. 



Such a proportion of nitrate, in a soil very 

 heavily manured, has nothing surprising in it ; 

 in fact, to incorporate a soil well mellowed with 

 stable-dung in an advanced state of decompo- 

 sition, with either ashes or marl — to dig it thoroughly, 

 so as to mix and let in the air to the whole mass 

 •^to form trenches to prevent stagnant water from 

 accumulating, is, in fact, equivalent to manuring, 

 and prepares a field to yield abundant harvests. Well, 

 a little reflection will show us that this is exactly 

 the process we adopt when we form aa artificial nitre- 

 bed. The only difference lies in that, in a moist cli- 

 mate, the nitre-bed ought to be sheltered, in order to 

 preserve in the earths salts so soluble as nitrates ; and 

 that, however little continuous it may be, the rain does 

 not fail to draw, or at least to penetrate into, the ad- 

 jacent subsoil. Thus, from the 9th to the 29th of 



August, it rained every day at Liebfrauenberg, and they 

 measured in the udometer 0,053 in. of water. The 

 29th of August, immediately after the rain had ceased, 

 we collected earth in the same bed from which we had 

 taken it on the 9th : after drying, 1 kilo, of this earth 

 yielded 0.0087 grammes of nitrate; consequently, in 1 

 cubic metre, the equivalent of 0.13 kilos, of nitrate of 

 potash, or 45 kilos, per hectare : the greatest part of 

 the saltpetre had, therefore, disappeared from the sur- 

 face of the earth. 



In the month of September it rained fifteen times, 

 and there fell 0.108 in. of water. On the 10th October,- 

 after fourteen days' drought, the soil of the kitchen- 

 garden, under the influence of a continued wind, had 

 lost its excess of moisture, and had become dry enough 

 to require watering. From earth taken from the foot 

 of a wall breast-high, after having been dried, was ob- 

 tained 0.298 grammes of nitre per kilo., or 447 grs. per 

 cubic metre, or 1.490 kilos, per hectare, which rather 

 surpasses that obtained by the dose on the 9th of Au- 

 gust. The alternations of drought and moisture the 

 soil had undergone, explain the enormous variations 

 that we have noticed in the proportions of nitrates 

 found in the soil. As to the great quantity of these 

 salts, it proceeds, beyond a doubt, from the prodigality 

 with which we manure, at all times, a kitchen-garden— 

 the true type of intense culture. It is proper, there- 

 fore, to apply doses of saltpetre to soils which never 

 receive manure, such as forest-lands, or which are only 

 slightly manured, as lands tilled under a normal culti- 

 vation. 



I have examined seven samples of forest-soil. The 

 earth taken on the 27th October in a forest of pines 

 near Ferreste, in the Upper Rhine, furnished no indica- 

 tions of nitrates. 



The earth of a pine-forest, situated on the summit of 

 a mountain of the Vosges, and in such a position as to 

 be watered only by the rains, contained, on the 4th of 

 September, the proportion of 7 grammes of nitrate of 

 potash per cubic metre. 



Sand taken on the 15 th October, in the forest of 

 Fontainebleau, contained per cubic metre the equivalent 

 of 3.27 grammes of nitrate of potash. 



In a heath soil collected on the 15th August, in the 

 forest of Hatten (a short distance from the Rhine), we 

 found the equivalent of 12 grammes of nitrate. 



In meadow-lands, taken in September and October 

 on the banks of the Saiier, in a valley of the Vosges, 

 and a pasturage situated near Roedersdorf (Upper 

 Rhine), the proportion of nitrate of potash has varied 

 from 1 to 11 grammes per cubic metre of earth. 



Of nineteen samples of arable earths, of good quality, 

 taken in September and October in the valleys of the 

 Rhine, the Loire, the Marne, and the Seine, four 

 yielded no nitre. The lands which contained the least 

 were taken from a field of maize at Hoerdt (Lower 

 Rhine), from the vineyard of Liebfrauenberg, and from 

 a field of beetroots on the banks of the Saiier. The 

 cubic metre of earth did not contain, respectively, more 

 than 0.8 grammes, 1.28 grs., and 1.35 grs. in equiva- 

 lent of nitrate of potash. 



I had not waited for this last result, in seeking nitrates 

 in the calcareous amendements which are applied to the 



