THE FARMER'S MAGAZINE. 



317 



or ammoDiacal fixed salts, susceptible of being converted 

 into carbonate volatile on contact v?ith the calcareous 

 matter vehich the earth in common contains, the defi- 

 ciency occasioned by volatilization of the ammonia will 

 become considerable. These fixed salts by their nature 

 will remain on the surface of the meadow without sus- 

 taining the least loss, until the rain causes them to 

 penetrate into the soil after having dissolved them. 



It therefore appears to me that nitrification has the 

 effect of giving |to the fertilizing azotous principles of 

 the compost a stability they would not have possessed 

 if they assumed or preserved the constitution of 

 ammonia. 



If we consider that the nitrates form at most only 

 1 -200th of the compost, we are led to ask if it would 

 not be more economic to apply directly to the meadows 

 the Peruvian saltpetre, rather than obtain the nitrate 

 acid in an enormous mass of materials, the transport of 

 which exacts from the teams a great expense of power. 

 The American nitrate of soda, costing 50 francs per 100 

 kilogrammes, by adding to it 500 grammes, having a 

 value of 25 to 100 kilogrammes of any kind 

 of earth, we shall obtain in the form of nitric acid, but 

 in that formation, the equivalent of a quintal (I cwt) of 

 the richest compost. 



That we may derive, even in Europe, great advantages 

 in the form of improvements from the Peruvian salt- 

 petre mixed with the slime of rivers or the scourings of 

 ditches, employed generally in the dressing of meadows, 

 is incontestible : the experiments of M. Kuhlmann and 

 Mr. Pusey leave no doubt upon that point. In the 

 meantime, a simple addition of saltpetre to mould can- 

 not constitute a true compost, the efficacy of which de- 

 pends also on phosphates and other substances, alkaline 

 and calcareous, brought by the materials of which it is 

 composed. 



Nitrification, wherever it manifests itself, follows at 

 first a progressive course, the rapidity of which in the 

 compost I should have wished to state, but I have been 

 prevented by the difficulty of deducting samples repre- 

 senting even approximately the mean constitution of so 

 considerable a mass composed of elements so different 

 and so unequally distributed. I have limited myself to 

 making the investigation on a well-manured soil, that 

 of the kitchen-garden of Liebfrauenburg, sufficiently 

 homogenous when we have separated from it the straw 

 and stones. 



Ten kilogrammes of earth well damped were laidpris- 

 matically on a sand-stone flag, and sheltered by a glass - 

 covering. When it was judged necessary, it was 

 sprinkled with distilled water free from ammonia. 



The day on which I began the experiment the earth 

 had been perfectly mixed, and we had taken from it 500 

 grammes in which we had dosed the nitric acid. We 

 had dosed several similar parcels between the 6th August 

 and the 2nd October. The following are the results 

 of these doses, the litre of dry and subsided earth 

 weighing 1 kilo. 300 : 



NITRATES EXPRESSED BY NITRATE OP POTASH DOSED IN 

 DRY EARTH. 



In 500 Grammes. Per cubic metre- 

 Grammes. Grammes. 



5th August, 1857 0.0048 .... 12.5 



17th „ , 0.0314 .... 81.6 



2nd Sept., ,, .... 0.0898 .... 233.5 



17th „ „ _... 0.1078 .... 280.3 



2ud Oct., „ .... 0.1033 268.6 



From the 5th August to the 17th September, in 43 

 days the production of nitre made rapid progress. The 

 quantity of saltpetre rose from 12.05 grammes, when the 

 little nitre-bed was established, to 280.03 grammes. 

 From the 17 th September to the 2nd October, the nitri- 

 fication remnined stiationary. 



At first sisjht the equivalent of 200 grammes of nitrate 

 of potash diffused in a cubic metre of earth will appear 

 a very feeble dose of azotous manure. But, in reality, 

 the earth is only the excipient of the fertilizing principles ; 

 it is therefore in the water by which it is penetrated that, 

 most generally at least, reside the agents destined to in- 

 terpose in culture. Now, 100 parts of the soil of Lieb- 

 frauenberg absorb, when completely saturated and with- 

 out changing its volume, 12 parts of water, say 546 

 kilogrammes per cubic metre. Every litre of water 

 absorbed will contain therefore the equivalent of 0.512 

 grammes of nitrate of potash. Arable land is still suffi- 

 ciently moistened when it retains no more than half the 

 water it is capable of absorbing : being then more accessible 

 to the air, it becomes more favourable to vegetation. In 

 that state every litre of water will contain 1.024 grammes 

 of nitrate, representing 0.172 grammes of ammonia, 



141 grammes of assimilable azote, the germ of about 



1 gramme of the proteons matter, the dry vegetable meat 

 that the plant is capable of organizing. 



I have already said that the compost owes not its 

 fertilizing properties to saltpetre alone. I have thought 

 that in order to complete the investigation it would be 

 proper to seek for the azote and the carbon, the phos- 

 phoric acid and the ammonia, as I had already done 

 with the vegetable earth, for these are the actual or 

 approximate elements of fecundity. 



The compost of the mai-ket-gardeners of Paris, which 

 I have more closely examined, is the result of the slow 

 decomposition of dung operated in the beds, established 

 to determine that vegetation as precarious as vigorous, 

 which is the true type of the most intense culture that it 

 is possible for man to practice. 



In order to form a hot-bed, we cover the soil with a 

 dressing of horse-dung, of 1 m. 40 wide, and m. 30 

 thick : we then water and press it strongly. Upon this 

 basis we depose the bed of earth from 0.15 to 0.18 

 deep, more or less, completed by previous preparation, 

 in which the plants develope themselves. 



When we take away the hot-bed, the dung that con- 

 stitutes the base is converted into an incomplete compost. 

 This is a new earth, very porous, which we leave to 

 acquire age by laying in heaps. There it subsides, be- 

 comes more dense, more homogeneous, more earthy ; it 

 is in this state that we form of it the upper stratum, the 

 cultivable soil of a new hot-bed. 



The compost obtained in one year not being employed 

 entirely in the formation of the hot-beds of the succeed- 

 ing year, there always remains an excess that the mar- 

 ket-gardeners sell for top-dressing the lawns of pleasure- 

 grounds. 



I have examined two specimens of compost, one hav- 

 ing been exposed on a heap for four or five months 

 belonging to a market gardener ; the other a new com- 

 post taken from a hot-bed of a garden belonging to M . 

 Vilmorin. The first was dosed with dry matter the 

 equivalent of 1.071 grams, of nitrate of potash per kilo- 

 gramme ; in the second, the equivalent of 0.940 grams, 

 of the same salt. With the magnifying-glass we per- 

 ceived in these composts fragments of quartz, very 

 limpid and colourless, small calcareous nodules, detritus 

 of vegetables more or less marred, having a brown tint 

 acquired from the peat. The compost has otherwise 

 much analogy with vegetable earth, as it is easy to satisfy 

 ourselves by comparing its composition with those of 

 different earths. 



1st. The mould of a kitchen-garden at Bischwiller, 

 near Haguenan : soil sandy, strongly manured. 



2nd. The light mould of the kitchen-garden of Lieb- 

 frauenberg. 



3rd. A very argillaceous earth, very strong, from 

 Bechelbronn, taken in autumn in a soil where wheat had 

 been hqrvpstpd. 



z 2 



