NA TURE 



465 



EXPERIMENTS ON THE GROWTH OF 

 WHEA T. 



The Rothamsled Experiments on the Growth of Wheat, 

 Barley, and the Mixed Herbage of Grass Land. By 

 William Fream, B.Sc. Lond., LL.D., Professor of 

 Natural History in the College of Agriculture, 

 Downton. (London: Horace Cox, Field Office, 1888.) 

 T^HE long series of reports which have emanated from 

 -i Rothamsted since 1847, and which lie buried to 

 most readers in the Journals of the Royal Agricultural 

 Society, as well as in those of our more purely learned 

 Societies, have long needed an editor. Back numbers of 

 serials are not particularly attractive to the modern reader. 

 The laborious papers by Sir John Lawes and his in- 

 defatigable colleague Dr. Gilbert would have run some 

 little danger of being buried alive had not an able editor 

 and exponent been found. Happily, Dr. Fream possessed 

 the necessary knowledge and discrimination for this task, 

 and, with the entire concurrence of the original investi- 

 gators, the upshot is a valuable digest of a certain section of 

 [the results obtained — namely, those relating to the cereals 

 and the grasses. The volume is adapted for reference 

 rather than for rapid reading, although the sections upon 

 the influence of climate on the cultivation of wheat, and 

 upon the home produce, imports, and consumption of 

 wheat, are less close in fibre, and may be scanned with 

 greater ease. The book is, in fact, rather for students 

 than for the omnivorous reader, but nevertheless appeals 

 to a very large constituency. All landlords, land agents, 

 land farmers, as well as agricultural students (now a 

 i numerous class), will welcome it as giving, in a compendious 

 form, and in digested condition, matter which is scattered 

 I through many periodicals. 



The results of continuous wheat and barley growing 

 year after year upon the same land — without manure of 

 lany kind, with annual dressings of dung, with annual 

 dressings of nitrogenous manures, with annual dressings 

 of mineral manures, and with annual dressings of mixed 

 nitrogenous and mineral manures — are all given. The 

 ijfact that wheat and barley have been grown for forty 

 years in succession without manure upon the same land, 

 I while the entire straw and grain have been removed, 

 is in itself striking, and still more singular is it that the 

 average produce during all these years is equal to the 

 average yield of Australia, and exceeds that of many of 

 the United States of America. It is also noteworthy that 

 the yield of the last crop comprised in these reports — 

 that of 1883 — is 13! bushels per acre, or within one- 

 fourth bushel of the average during the entire period of 

 forty years. With regard to manures, minerals alone 

 have added very slightly to the unmanured produce ; 

 whereas, manures containing nitric acid alone, or some 

 easily nitrifiable compound of nitrogen, have considerably 

 increased the crop. Manures consisting of potash, phos- 

 phoric acid, and nitrogen in the form of ammonia salts 

 or nitrates, are able to grow heavy crops of wheat con- 

 tinuously. It is clearly shown that such compounded 

 fertilizers, containing both the mineral and nitrogenous 

 constituents of plant food, can grow crops superior to 

 Vol. xxxviii. — No. 985. 



what are produced by annual dressings of fourteen tons 

 per acre of farmyard manure. Also the proportion of 

 the nitrogen applied which is made use of by the growing 

 crops is much higher in the case of the artificial fertilizers 

 than in the case of the farmyard manure. A larger pro- 

 portion, in fact, of the nitrogen applied is recovered by 

 the crop in the case of the artificial dressings. On the 

 other hand, the residuary effect of nitrogen applied in 

 combination with carbon (as in farmyard manure) is 

 much greater than in the case of applications of prepared 

 salts of ammonia or of nitric acid. 



The ease with which fertility can be kept up by 

 artificial applications forms, in the opinion of many 

 agriculturists, a reason for discarding the more cumbrous 

 method of keeping up the fertility of land by means of 

 live stock and the dung-cart. But it must be remembered 

 that no artificial manure accumulates fertility in a soil 

 like farmyard manure, and its nitrogen, being liberated 

 gradually, is available over a long series of years, and 

 especially so at those seasons of the year in which 

 vegetation is most in need of it. 



The grass experiments are of great interest. First, we 

 have the different quantities of hay produced by various 

 dressings of manurial substances ; but more remarkable 

 are the changes brought about in the species of grasses 

 predominating on various plots by the influence of 

 fertilizers applied during a long series of years. On 

 the plot, for example, to which ammonia salts have 

 been continuously applied for thirty years, the total 

 number of the species originally extant has been much 

 reduced, three-quarters of the produce being composed 

 of Fesluca ovina and Agrosiis vulgaris. The leguminous 

 herbage has disappeared. On the plot manured con- 

 tinuously with superphosphate, the number and relative 

 predominance of the plant species is much the same 

 as without manure, with a prevalence of Lathyrus 

 pratensis among the Leguminosas, and an increase of 

 Ranunculus repens, R. bulbosus, Achillea Millefolium, 

 and Rumex Acetosa. Again, when ammonia salts and 

 mixed mineral manures are applied, Poapratensis becomes 

 the prevailing grass. These examples must suffice to show 

 the great changes wrought by continuous applications, and 

 the principle of the survival of the fittest under regulated 

 alterations of the environment. 



Complicated and multifarious as are these experiments, 

 the general conclusions for the guidance of agriculturists 

 are reducible to a few simple deductions. Thus the 

 superior excellence of nitrate of soda as a fertilizer for 

 cereals and for grasses is distinctly shown. The necessity 

 of nitrogenous manures, such as nitrate of soda and 

 ammonia salts, as means of bringing out or developing 

 the effect of the so-called mineral manures, such as potash 

 and phosphates, is constantly proved. The comparatively 

 small value of many constituents of plants (owing to 

 their already existing in sufficient quantities in most 

 soils), such as soda, magnesia, and silica, is also placed 

 beyond doubt. The residual effect of farmyard manure, 

 and its consequent power of not only keeping up but 

 indefinitely increasing the fertility of a soil, are points 

 greatly in its favour ; while the slowness of its action, and 

 the very small proportion of its nitrogen which appears 

 to be recoverable at any particular time, are considerations 

 which weigh against it. The residual effect of mineral 



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