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JOUBNAL OF HOBTJCTJLTURE AND COTTAGE GABDENER. 



[ July 23, 18W. 



formation to the horticulturist, although hardly knowing in what 

 manneT to treat the subject, for the simple reason that the horticnl- 

 tnrist was far in advance of any theory that could be laid down to 

 regulate his proceedings. The agriculturist, on the other band., was 

 far behind the horticulturist in practice, though well aware of some 

 of the great principles which should guide him in the application of 

 manures. It was within the agriculturist's power to increase the crop 

 in an average season by the judicious application of farmyard manure, 

 and in the event of tho supply of dung running short, he could apply 

 artificial manures in certain proportions which experience had shown 

 would produce a particular effect on the crop. The farmer, by experi- 

 ment, had learnt precisely what to do in order to attain his object — 

 when to give a supply of manure, and when to withhold it, and he also 

 knew what particular hinds of manure were useful at certain stages of 

 growth, and when to withhold them. A gardener, as a rule [no, no], 

 could command any amount of stable manure, whilst the agriculturist 

 was not in such a favourable position, being often compelled by the 

 force of circumstances to eke out his deficiency by using certain arti- 

 ficial manures, generally expensive even when applied in the best 

 manner. Dr. Voelcker then. said he would arrange his remarks under 

 the following heads : — First, The nature of the organic and mineral 

 food of plants ; secondly, the properties of ordinary stable manure and 

 artificial mauares ; thirdly, the time of application ; and fourthly, the 

 fertilising combination and the special uses and effects of manures. 



In the first place, in reference to nitrogen, he considered a supply 

 of it necessary to growing plants. This was one of the questions 

 upon which there is a good deal of dispute among scientific men. 

 Nitrogen was not absorbed by plants directly from the atmosphere, 

 which, however, contains small quantities of ammonia, which are 

 absorbed by a porous soil or by rain, rain carrying with it at the same 

 time small quantities of nitric acid. He would, therefore, to insure 

 the healthy and luxuriant growth of garden plants, make use of 

 nitrogenous manures. Then the question would arise, In what form 

 was tbis nitrogenous food best supplied to plants ? He would supply 

 it in the Bhape of ordinary dung, in which it is to be found as a 

 nitrogenous substance in a progressive state of decomposition, partly 

 as ammonia, and partly in the form of nitric acid. Mineral manure, 

 ■which could only he derived from the soil, was not only essential to 

 the existence of plants, hut absolutely necessary for the luxuriant 

 development of every kind of produce. In this sense lime was as im- 

 portant as potash, sulphuric acid as phosphoric, soluble silica as any 

 other mineral composition which entered into plants. There were 

 certain matters spread throughout the soil that occurred in very small 

 quantities, while others were of more abundant distribution. The 

 alkalies, potash more especially, on some descriptions of land were more 

 Bparsely distributed than the corresponding soda or magnesia. Then, 

 as to the combinations on which plants feed, nitrogen is always present 

 in great variety, so that if in one form it fails to exert its beneficial 

 influence, it will be sure to do it in another, and this is of great prac- 

 tical advantage. Sulphate of ammonia and nitrate of soda are 

 especially useful to the growing plant ; but if applied at the wrong 

 time they are very dangerous. Experiments had been carried on in 

 Germany during the last four or five years with plants which ordinarily 

 grow on arable land, and which had been successfully cultivated in 

 various solutions, but if the solution was too strong the development of 

 the plants was greatly interfered with. Great care should be exer- 

 cised in using manures which are quick in their action, and he ques- 

 tioned whether they should be used at all, but he would recommend 

 good top-dressings. If good results were to be secured from the appli- 

 cation of phosphoric acid, potash, ammonia, and nitrates for horti- 

 cultural purposes, these ought to be mixed with a large mass of soil, 

 and used iu the form of a compost. He was of opinion that manure 

 could not be applied too early in autumn, and if thoroughly mixed 

 with the soil it entered into a great variety of combinations favourable 

 to the growth of plants. All soils possessed the remarkable property of 

 fixing some of the more fertilising ingredients of manure, provided 

 sufficient rain fell to enable the ground to do so. With regard to the 

 -effects of certain manures upon plants, he found that these affected 

 not only plants, but also particular parts of plants. No doubt the 

 application of phosphate manures had done much to bring root cropB 

 to that perfection in which they were seen at shows. If the regular 

 Bupply of phosphates were withheld, he believed root crops would 

 return to their original fibrous condition. By the application of 

 strong forcing manures, containing mineral matters as well as nitrogen, 

 to which element their forcing action was mainly due, leaf-growth 

 would be obtained at the expense of well-ripsned wood and fruit. 

 Other manures promoted early maturity, which was of especial import- 

 ance to fruit-growers, and to this result a combination of phosphatic 

 manures with potash contributed. Potash and phosphate of lime, as 

 in mixtures of the latter and wood ashes, gave, perhaps, a better 

 crop of fruit than any kind of manure. The best form in which 

 phosphate of lime could be applied for the purpose of growing fruit 

 was that of bones partially deprived of their nitrogenous matters, of 

 which they contain too much to be useful for fruit-growing in great 

 perfection, more especially Grapes. Better fruit was often produced 

 by using only half tho quantity of manure. An artificial manure con- 

 taining a good proportion of potash was often of great use, provided the 

 potash was not in too large quantity, when it retarded rather than 

 forwarded the development of plants. If land were of a sandy nature 

 a limited mixture of salts of ammonia would he found very useful. 



fei some experiments which he had recently tried, he had increased th& 

 produce of a crop of Potatoes by the following dressing — viz., 4 cwt. 

 of superphosphate, 2 cwt. of potash, and 2 cwt. of ammonia, costing 

 33s. per acre. The produce amounted to between 12 and 13 tons, 

 while an unmanured portion only produced 6 tous per acre. This 

 showed what could be done by a proper selection of manure. He had 

 also tried another experiment, using only superphosphate and potash, 

 omitting the ammonia, and the result was that the crop fell short by 

 3 or 4 tons, thus showing the great service rendered by the ammonia. 

 He believed that there was a great field open for investigation with 

 reference to the supply of manure to fruits. Within the last few years 

 several fruit-growers had dressed their Gooseberry bushes with artificial 

 manures, and with great success. In pot-culture they should not apply 

 any strong quick-acting manures, but they should prepare a compost, 

 and use it with discrimination. 



The Chairman said he believed there were some gentlemen present 

 who took rather a different view from that of Dr. Voelcker, especially 

 upon the source of the supply of nitrogen to plants, and he would, 

 therefore, invite discussion upon the subject. 



The Rev. C. P. Peach remarked, that of the various constituents 

 contained in plants, nitrogen rarely existed to the extent of more than 

 2£ per cent. In grain, analysis gave ns *2h per cent., and in the caseof 

 Potatoes about 0.7 per cent., and this after the materials had been partly 

 deprived of their hydrogen and oxygen. He thought it was going too 

 far to say that nitrogen was of more value in a plant that any other 

 substance ; the carbon, for instance, amounted to 50 per cent, of the 

 whole. Nitrate of soda and ammonia formed the only two useful in- 

 gredients of the chemicals sold for manuring purposes. Ammonia 

 had very great power in dissolving carbonaceous matters and rendering 

 them available for the food of the plants, which, when growing, took 

 their carbon principally from the soil, and he was inclined to think 

 that in this lay the great value of ammoniacal substances. It was 

 commonly stated that a plant could obtain the hydrogen which it 

 required from water, but his opinion wa3, that it was obtained more 

 easily from ammonia. Silica was one of the most insoluble substances, 

 but plants took it up by the roots, its solution being facilitated by 

 alkaline salts, and hence the value of nitrate of soda. He thought 

 silica was more valuable than nitrogen to the plant. He considered 

 that, though temporarily guano might be of great service, its effects 

 were not permanent. Nitrogenous matters were important as facili- 

 tating the formation of diastase, which as a solvent of starch was of 

 the highest importance in plant nutrition, and on this account, rather 

 than for any direct value, nitrogen was important. 



Dr. Gilbert remarked that Mr. Peach's statements concerning the 

 per-centage of nitrogen in various crops was irrelevant. It was a 

 question which had been under discussion for the last thirty years, 

 and most elaborate experiments had been made. Boussingault and 

 Ville had come to the conclusion that free nitrogen is not absorbed by 

 plants, and the latter was at the present time making quite a sensa- 

 tion in France by his advocacy of nitrogenous manures. Mr. Lowes' 

 and himself had worked for several years to determine this question, 

 and their conclusions were, that if nitrogenous substances were with- 

 held, and only free nitrogen had access to the plant, no increase in the 

 quantity of nitrogen in the plant took place ; but when a small quan- 

 tity of ammonia was given, it showed its effects in less than twenty- 

 four hours. Mr. Peach had stated that the small quantity of carbonic 

 acid contained in the atmosphere was insufficient for the proper deve- 

 lopment of plants, but he considered there was an ample supplyin 

 water and the air. The presence of an increased per-centage of silica 

 did not strengthen straw, as he had found that in almost all cases 

 the best standing crop was that in which the lowest proportion of silica 

 was found. In approving of the manner in which Dr. Voelcker had 

 brought the subject forward, Dr. Gilbert stated that horticulturists 

 would have to carry out many experiments before they would be able 

 to get at the principles which had been so long arrived at in agricul- 

 ture. The horticulturist had a far larger field for experiment than 

 the agriculturist, in the vast number of his products and the wonderful 

 control he had to exercise over the growth of plants. At present they 

 had arrived at some useful results — results, perhaps, not quite con** 

 elusive, for they must not look to obtain from a few years' experiments 

 the conclusions which they would eventually succeed in arriving at. 



Major R. Trevor Clarke fully concurred in Dr. Voelcker's views 

 with regard to manures applied in a solid form being more beneficial 

 than those in a liquid state. One of their most clever Rose-growers, 

 who was present (the Rev. Reynolds Hole), was well aware of their 

 superiority. Great development in root crops and fruit was mainly 

 due to the use of manures rich in phosphates, and he thought there 

 was a very good field open for physiologists to experiment in ; for in- 

 stance, in causing plants to revert to their original state, or to develope 

 into new races. 



Mr. D. T. Fish said that if the gardener desired a good crop of 

 Roses he must have rich manure. The farmer was content with one 

 crop where the gardener required three, and therefore it was necessary 

 that the gardener should use a much greater quantity of stable manure. 

 The time of applying it had also a very great effect upon the crop, 

 and he had found that those farmers who left the manure upon the 

 top of the ground in winter had the best crops. Soluble manures 

 were certainly those which accomplished tho greatest good. He be- 

 lieved that the atmosphere contained sufficient material for the food 

 of plants without much aid from the soil, and he should account for 



