320 



THE FARMER'S MAGAZINE. 



ON COMPOST AND VEGETABLE EARTH. 



[tUANSLATED -from the " JOURNAL d'aGRICULTURE PRATIQUE."] 



{Continued.) 



In the preparation of compost, nitrification is not the 

 main object, and the measures we adopt are frequently 

 very unfavourable. Thus, when local circumstances 

 allow it, we overload with urine, night-soil, blood, &c., 

 and that only a short time before the compost is spread 

 over the meadows. This is a most defective plan in 

 regard to the success of nitrification. Practice teaches 

 us that in the quantity of animal matters intermixed, 

 there is a limit which cannot be exceeded with impunity, 

 and the very conclusive experiments communicated to 

 the Academy by M. Peloaze prove that if these matters 

 predominate, not only will they be unfavourable to ni- 

 trification, but that they even destroy the nitre already 

 formed, by transforming the nitric acid into ammonia. 

 The saltpetre works, therefore, suspend the use of them 

 many months before the time fixed for the lixiviate. 

 During this last period the moistening of the earths is 

 only affected with water. 



A short time after I had presented to the Academy 

 my researches into the quantity of nitrates contained in 

 the earth and the waters, an English agriculturist of the 

 first character advised the cultivators to establish arti- 

 ficial nitre-beds. I will not go so far as that. Although 

 my conviction of the utility of saltpetre in the fertiliza- 

 tion of the soil is very profound, I shall limit myself 

 to proposing that in the compounding of composts, whether 

 for the farm, the kitchen-garden, or the flower-garden, 

 we follow, so far as circumstances will permit, the pre- 

 scriptions recommended for the establishment and 

 management of a nitre-bed. For this object I have 

 placed at the end of my memoir an extract, which I shall 

 not repeat here, from the instruction, so remarkable, for 

 which we are indebted to the former stewards-general of 

 gunpowder and saltpetre. 



Let us now examine the utility of the nitrification 

 accomplished in the compost. 



The efficacious matter contained in a pulverulent 

 manure, spi-ead over a high meadow, will penetrate into 

 the soil only after having been dissolved by rain or dew, 

 and if these media are wanting they will remain ex- 

 posed to the winds and sun. Let us admit that the 

 fertilizing azotous elements are carbonate of ammonia, 

 or ammoniacal fixed salts, susceptible of being converted 

 into carbonate volatile on contact with the calcareous 

 matter which 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 (1 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 eflBcacy 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 difliculty of deducting samples repre- 

 senting even approximately the mean constitution of so 

 considerable a mass composed of e)i ^ents so different 

 and so unequally distributed. I have imited 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 laid pris- 

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

 covering. When it was judged necessary, it was 

 sprinkled with distilled water free from ammonia. 



The day on (vhich 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 OF 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 



2nd Oct., „ .... 0.1033 .... 268.6 



