542 



THE FARMER'S MAGAZINE. 



Experiment C. : Vegetation of the Helianthuses under 



the influence of the phosphate of lime, ashes, and 



bicarbonate of potash. 



We have just seen that the introduction of saltpetre, 

 combined with phosphate of lime in the soil, determined 

 a considerable development of organic matter, and the 

 assimilation of more than 130 grains of carbon. The 

 Helianthuses grown in these conditions presented nearly 

 the same aspect, and the same vigour as those which had 

 been cultivated in the open ground. A complete manure, 

 in which the plants found all they wanted, was then 

 formed from the combination of nitre with the phosphate 

 and the ashes. 



The experiment C was undertaken to ascertain what 

 share of influence upon vegetable production must be 

 attributed to the phosphate of lime. To that effect, the 

 saltpetre was suppressed ; but as this suppression did 

 away with a considerable quantity of alkaline matter, 

 the nitre which had been used in the experiment B was 

 replaced by its equivalent of bicarbonate of potash — a 

 salt much less alkaline than the carbonate. It is, be- 

 sides, the bicarbonate that is found in the dung and the 

 urine which herbivorous animals drop upon their pas- 

 ture. 



The constitution of the soil, in the two experiments 

 B and C, was as follows : 



Exper. B. Exper. C. 

 Grains. Grains. 



Earthenware 9-300 9-300 



Broken bricks 6-200 6-200 



Uuartzy sand 159030 159-030 



174-530 174-530 



Phosphate of lime 155 000 155-000 



Ashes 7-750 7-750 



Nitrate of potash 21*7 gr. 

 and bicarbonate 



of potash 19-530 gr.. 



Containing : 



Potash 10-1060 10-1060 



Soluble nitrogen 30535 — 



Everything in both soils was then equal on either side, 

 with the exception of the soluble nitrogen of the nitric 

 acid, which was wanting in the experiment C. 



On the 5th of July, two seeds of helianthus, weigh- 

 ing 1'6585 grains, were sown. 



On the 20th of August, the first normal leaves were 

 withered. 



Length. Width. 



2nd normal leaves. . 316 Sths of inch. . 1000 8th of inch 

 4th „ .. 2-84 „ .. 1-000 



5th „ .. 1-58 „ .. 0-632 



These leaves were of a very pale greeOu 

 Each of the plants bore a bud — height 43 and 44 

 eighths of an inch, the diameter of the stems 0*316 

 eighth of an inch. 



On the 30th of September the plants had not 

 changed their appearance since the 20th. Both had a 

 yellow flower, extremely small, but well formed. Just 

 as in the experiment A, in which nothing had been put 

 in the soil, limit plants were obtained. 



Grains. 



The two dried-up plants weighed 7*7190 



The seeds 1-6585 



Organic matter developed 6 0605 



As in the experiment A, the plants remained pretty 

 strong up to a couple of months. Afterwards, the 

 leaves withered towards the lower end of the stem, and 

 the strength of vegetation rapidly decreased. 



Analysis showed in the dried-up Plants and in the Remains 

 left in the Soil : — Grains. 



Nitrogen 0-08990 



Found in the seeds 0-04805 



Nitrogen acquired in three months of vegetation in 



the open air 0-04185 



CARBON FIXED DURING VEGETATION. 



The organic matter weighed 6'0605 grains. Admitting 

 0-40 for the proportion of carbon, we find 2-4242 

 grains for the weight of that substance, or 913-24 cubic 

 eighths of an inch of carbonic acid gas. 



Vegetation having lasted 86 days, the plants must 

 have assimilated, every 24 hours, on an average, the 

 carbon of 10-2334 cubic eighths of an inch of carbonic 

 acid gas. It is within 3-16 eighths of an inch of what 

 the helianthuses had assimilated in the experiment A. 



I shall resume here the facts elicited by the three 

 experiments : 



Carbonic Acid 

 Weight of Gas decom- 



the dried Pro- Vegetable posed by the 

 duce, the Matter Plants every 



Seed being 1. formed. 24 Hours. 



Cubic Sths of 

 Grains. Grains. an Inch. 



Experiment A — 

 The soil having 



had nothing.. 3-6 4-4175 7-742 

 Experiment B— 

 The soil having 

 received phos- 

 phate, ashes, 

 nitrate of pot- 

 ash 198-3 237-2205 568-30 



Experiment C — 

 The soil having 

 received phos- 

 phate, ashes, 

 bicarbonate of 

 potash 4-6 5-0605 1080 



ABSORBED BY THE PLANTS IN EIGHTY-SIX DAYS OF 

 VEGETATION. 



Carbon. Nitrogen. 



Grains. Grains. 



Experiment A — 



Soil having had nothing . . 17670 003565 



Experiment B — 



Soil having received phos- 

 phate, ashes, nitrate of 



potash 130-8820 2*58230 



Experiment C— 



Soil having received phos- 

 phate, ashes, bicarbonate 

 of potash 2-4180 0-04185 



The influence of nitrous manure upon the develop- 

 ment of vegetable organism is now proved in the 

 clearest manner. The helianthuses grown in a soil 

 treated with saltpetre and phosphate, reached the same 

 growth as they would have done in a fertile soil. They 

 assimilated 130-82 grains of carbon. Seeds containing 

 only 0-2945 grains of albumen, produced, owing to the 

 effect of saltpetre, plants in which there were more 

 than 15"5 grains of that substance. 



In a soil destitute of any nitrous matter, with or 

 without the presence of phosphate of lime and alkaline 

 salts, the helianthuses did not grow much beyond five 

 inches. In acting upon the carbonic acid of the air 

 scattered in or dissolved in water, they did not even 

 assimilate 3 grains of carbon ; and the nitrous principles 

 of the atmosphere which intervened in these circum- 

 stances did not impart to the plants more than 00465 

 grains of nitrogen. These results prove that, in order 

 to help actively vegetable production, Basic phosphate 

 of lime and alkaline salts must be associated to a sub- 

 stance containing some soluble nitrogen. Farmyard 

 manure, especially, generally offers this kind of asso- 

 ciation. 



In these experiments, when saltpetre was not used, 

 the 0-033 and 0-04G5 grain of nitrogen acquired by the 

 plants after three months' vegetation, very probably came 

 from the ammoniacal vapours arising from the nitrous 



