540 



THE FARMER'S MAGAZINE. 



NUTRITION OF PLANTS. 



RESEARCHES UPON THE INFLUENCE EXERCISED BY THE SOLUBLE NITROGEN OF MANURES, IN 

 THE PRODUCTION OF VEGETABLE MATTER. 



ACTION OF PHOSPHATE OF LIME UPON VEGETATION, WITH AND WITHOUT THE CONCURRENCE OF 



SALTPETRE. 



Translated from the French of BoussingauU, 

 By M. R. de LA Trehonnais. 



In a memoir read to the Academy, in its sitting of the 

 19th of November, 1855, I demonstrated how much 

 nitrates were favourable to vegetation. With the same 

 meteorical conditions, in soils of similar nature, helian- 

 thuses, put to the regime of nitrate of potash, have taken 

 a considerable development ; they have elaborated 9.30 

 grains of albumen, and produced 108 times as much 

 vegetable matter as was contained in the seed. Without 

 nitre, on the contrary, when the available nitrogenous 

 principles of the atmosphere have alone intervened, the 

 growth of the plant was more restricted. After three 

 months' cultivation, there was scarcely 0.465 grain of 

 albumen formed, and the dried helianthuses weighed only 

 three or four times as much as the seed. 



The experiments made upon alenese cresses have led 

 to similar and perhaps more certain results, because 

 in the comparative observations, the plants had both 

 had at their disposal in the ashes of dung added, much 

 more mineral substances than they could absorb. But 

 was this the case with the helianthuses ? We must in- 

 quire, for instance, if, on account of the rapidity of its 

 growth, the one which had a supply of nitrate, did really 

 meet in the soil a sufficient quantity of phosphate of 

 lime ; and in admitting that such had been the case, we 

 should still bejustified in asserting that the development 

 of the helianthus raised without nitrate would have been 

 more conspicuous, and that the carbon, the nitrogen, the 

 elements of water would have been assimilated in larger 

 proportions, if the plant had found in the soil as much 

 potash as the saltpetre had supplied to the other heli- 

 anthus. 



It was to clear up these doubts that I undertook 

 new researches. I was anxious, besides, to see a fresh 

 manifestation of certain facts which had unexpectedly 

 occurred in my former experiments— I mean the so de- 

 cided action of the soluble nitrogenous principles 

 Upon the formation of the immediate organs and prin- 

 ciples of vegetables— an action so manifest, that the 

 weight of the organism elaborated by a plant gives in 

 some measure the proportion of nitrogenous manure 

 which it has assimilated. This is so true, that a seed so 

 minute that the proportion of albumen should scarcely 

 be traceable— as in Miinuhis spcciosus, tobacco, &c. — 

 produces in a barren soil a plant the development of 

 which does not go beyond the appearance of the rudi- 

 mentary leaves, and which preserves this embryonic 

 form during whole months, awaiting the manure indis- 

 pensable to constitute the nitrogenous tissue, without 



which it could not grow, because it can be of no use. 

 It is this stationary condition, this persisting germina- 

 tion, that for the first time I had an opportunity to 

 observe, in 1854, upon several seeds, the weights of 

 which ranged between 1-1 7th and l-68th part of a mil- 

 ligrame=0.0155 grain. {Calandrinia umbellata, and 

 Campanula baldensis.) 



I have observed, besides, that extremely light seeds, 

 weighing from 2 to 3 milligrammes, like cresses, pro- 

 duce, when sown upon an absolutely barren soil, slight 

 and delicate plants — provided, however, with complete 

 organs ; but then, as it appears from all my experiments, 

 without any exception, after several months' existence 

 in the open air, and moreover in a confined atmosphere 

 the plant does not weigh much more than the seed 

 from which it sprung; as if the extension of its organism 

 was found limited by the quantity of nitrogenous 

 principles contained in the seed. 



Tims there are seeds which possess the nitrogenous 

 element just necessary, without the aid of manure, to give 

 birth to a plant excessively reduced in its dimensions, 

 but perfectly organized, which I have designated by 

 Vne nd.mt oi limit plant , because it represents a plant 

 constituted with the least possible matter : in it is very 

 nearly found the nitrogen of the seed ; and slight though 

 it be, this plant blooms and bears a fruit which would 

 want only a fertile soil to regenerate the normal plant. 



The object of the experiments which I am going to 

 describe was at first to ascertain the action of the phos- 

 phate of lime upon vegetation with and without the help 

 of saltpetre. 1 have followed the development of the 

 Helianthus argophyllns in the open air, sheltered from 

 the rain, in a soil formed of pulverized burnt clay 

 mixed with quartzy sand. The vehicle, like (he pot 

 which contained it, had been calcined after being 

 washed in distilled water. Three experiments, A. 



B. and C, were prepared. In the experiment A. 

 nothing was added to the soil. In the experi- 

 ment B. basic phosphate of lime, vegetable ashes, 

 and nitrate of potash were added. In the experiment 



C, the soil received phosphate of lime, vegetable ashes, 

 and a quantity of bicarbonate of potash, containing pre- 

 cisely the same alkali as in the nitrate used in the ex- 

 periment B. 



The phosphate of lime had been extracted from calcined 

 bones, in using agents as pure as possible, on account of 

 the presence of magnesia. Notwithstanding this precau- 

 tion, the phosphate precipilatcd by the potash was not free 



