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36 



The Weekly Florists^ Review* 



August 20, 1908. 



such elaborated food as they may re- 

 quire. 



Such tubercles may be found on the 

 roots of beans, peas, or, in fact, on al- 

 most any of the leguminous plants. 



Whether the bacteria can take nitro- 

 gen from the air may well be doubted, 

 but it is a pretty well established fact 

 that they can extract nitrogen from com- 

 binations that are beyond the power of 

 higher plants. So firmly has the belief 

 in this association been established that 

 it has become the practice to inoculate 

 the soil with the proper bacteria when 

 legumes are to be grown on soil where 

 their natural symbionts are lacking. 



This inoculation is often made by the 

 transfer of some soil from a fertile field 

 to the new location. One can obtain on 

 the market pure cultures of bacteria suit- 

 able for various crops, and sow with the 



it. Among our cultivated plants which 

 depend more or less upon the heip of the 

 root fungus, we may mention some of the 

 orchids, gerardias, polygalas, some eri- 

 caceous species and many others. If you 

 will examine some of these plants, or, to 

 be more exact, if you will place a thin 

 section of their root on the stage of a 

 microscope having a magnifying power 

 of about 900 diameters, you will be able 

 to trace the mycelium of the fungus in- 

 vesting with its anastomosing fibers the 

 outside of the root and penetrating 

 through the epidermal cells of the host. 



The Work of Ferments. 



In speaking of the ferments Ave are 

 prone to infer that the work is all done 

 by the micro-organisms already referred 

 to, but it seems that still more important 

 in the economy of plant as well as ani- 



'>*?■' 



Scene of this Week's Convention of the ^. A. F. 



(Cataract and International Hotels, at NlaRararFalls.) 



seed. That the use of these cultures is 

 not uniformly successful does not dis- 

 prove the theory, but rather indicates 

 that the preparations are at fault or 

 that they are not properly applied. 



Qover as a Fertilizer. 



Long before those relationships were 

 known, tlie fact was realized that if a 

 good crop of clover could be grown upon 

 a field it could safely be relied upon to 

 grow a good crop of corn or wheat the 

 succeeding year, and this notwithstand- 

 ing the fact that the clover had been cut 

 and removed in the form of hay, the ex- 

 tensive root system of the clover, with 

 its stored nitrogen, being sufficient for 

 the succeeding crop. 



The action of fungi of the unicellular 

 type in breaking down organic com- 

 pounds has long been recognized, and put 

 to use in many industries — witness the 

 jeasts and other ferments of this class — 

 but their mutual relationships with the 

 higher plants are subjects of quite re- 

 cent inquiries. To recur to the stat<»ment 

 in regard to the fungus and the beech, 

 we find that in this case we have a 

 fungus of a higher and much more com- 

 plex organization, a fungus which, in- 

 stead of b(>ing a microscopic unicellular 

 plant or a collection of similar cells, is 

 really a structure having organs highly 

 diflferentiated and making in some stages 

 of its growth a conspicuous object to the 

 naked eye. Here, too, it is believed that 

 a symbiotic relationship is maintained, 

 and that the mycorrhiza, in return for 

 the nitrogen secreted for the higher 

 plant, takes its pay in starch or sugar 

 which it is unable to make for itself. 



Investigation shows many cases of 

 symbiosis between plants containing 

 chlorophyl and those which are without 



mal life are the unorganized ferments 

 or enzymes. It now seems likely that 

 these enzymes may have an important 

 bearing on the fertilizer question. Just 

 what tlie nature of these substances may 

 be, at the present time we do not know, 

 as it is difficult to collect them in a pure 

 state. That they are highly nitrogenous, 

 however, is generally believed. But it is 

 their action which concerns us most. It 

 is said that these ferments bring about 

 changes by their mere presence, or at 

 least without loss of their own- sub- 

 starito. That is what is called catalytic 

 action, just as the presence of certain 

 metals in a solution will precipitate other 

 metals. 



These enzymes exist in all parts of 

 the active tissues of the plant, and are 

 found in abundance upon the growing 

 point of roots. They evidently have the 

 power of reducing the starches, fats and 

 ))roteids to 'forms which can be directly 

 assimilated and used- in the building up 

 of tissues. In fact, it appears that it is 

 to the work of those enzymes that the 

 bacteria and other simple forms of vege- 

 table life owe their power of rendering 

 up in such a remarkable degree the nitro- 

 gen contained in albuminoids and other 

 compounds. The enzymes have been 

 studied principally as they appear within 

 the plant body. They are not themselves 

 organized, and arc products, not parts, 

 of the vegetable cell. They can bring 

 about their characteristic changes as well 

 outside as inside the body; and an inter- 

 esting question is how far these sub- 

 stances may extend outside the plant 

 body, and if it is not possible that in 

 some genera of plants the work of col- 

 lecting nitrogen from the soil is due di- 

 rectly to them without the intervention 

 of the fungus. 



Physical Condition of Soil. 



In discussing the fertility of the soil, 

 there are other factors than the presence 

 of chemical elements necessary for plant 

 food. The food must be accessible, there 

 must be a supply of water for solvent 

 purposes, and there must be a sufficient 

 amount of heat to encourage the action 

 of the dissolving agencies. The physical 

 condition of the soil plays a very impor- 

 tant part in determining the fertility of 

 the soil. Air and water are not usually 

 spoken of as fertilizers, but they, never- 

 theless, are vital to the success of the 

 plant. The soil must be of such charac- 

 ter that the air can circulate among the 

 particles and come in contact with the 

 rootlets. The soil must also be in such 

 condition that it will hold a certain 

 amount of water, and it must be of such 

 consistency that the root hairs can visit 

 every little grain of earth in search of 

 nutriment. . 



The soil must not be so fine as to ob- 

 struct the free passage of air and water,' 

 nor so coarse as to allow either to flow 

 through in currents. What we need is a 

 happy medium, where the spaces between 

 the soil particles are such that a mere 

 film of water encirdes every one, or what 

 is called hygroscopicKholding of moisture. 

 In this condition l^e soil is capable of. 

 absorbing and hold^g the greatest pos- 

 sible amount of iij^rtrients in a readily 

 accessible manner, ^jn this condition, too, 

 •it will maintain a ^ore equable tempera- 

 ture and become f?a more comfortable 

 home for nutrifying^^ bacteria. This phys- . 

 ■ ical condition of the soil is brought 

 about by tillage, and it is frequently the 

 case that proper hauv^ling of the soil 

 makes all the aitference between success 

 and failure. 



Reasons for Loss of Fertility. 



So much for some of the factors which ' 

 we have to consider in increasing the 

 fertility of our fields, and now let us 

 consider briefly some of the causes of 

 loss of fertility. We are apt to attribute 

 loss of fertility entirely to absence of 

 available plant food. That such is not 

 always the case will be evident to anyone 

 who has had long experience in garden- 

 ing operations. 



In the originally fertile farm lands of 

 central New York, where a rotation of 

 corn and wheat and clover, or wheat, 

 clover and grass, or something of that 

 kind, was pursued for long years, we 

 heard complaints of lessening fertility. 

 The land would no longer grow clover, 

 or, as the farmers expressed it, the land 

 was * ' clover sick. ' ' This land still grows 

 a fair crop of corn or potatoes or the 

 grasses, but clover must be given a rest; 

 and is uncertain. 



After a few years' rest, probably, the 

 clover grows again. There are failures 

 of other crops, it is true, failures which 

 are often, and perhaps justly, attributed 

 to exhaustion of the soil, or at least of 

 certain of the elements. The theory is 

 that the land must be rested or a rota- 

 tion pursued which will allow of a recov- 

 ery or a renewal of the missing element. 

 It is such occurrences which have been re- 

 sponsible for our systems of rotation of 

 crops. 



Is the Soil Exhausted, or Poisoned ? 



The unsatisfactory part of this ex-, 

 haustion theory is that, no matter how 

 much fertilizer we may supply, we can- 

 not get certain crops to succeed them-, 

 selves annually through a long series of 

 years and give satisfactory returns, while 

 certain other crops can be grown annu- 

 ally on the same plot for a generation 



