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A FORTNIGHTLY REVIEW 



0? THE 



IMPERIAL DEPARTMENT OF AGRICULTURE FOR THE WEST INDIES. 



BOT 

 GA 



Vol. XI. No. 267. 



BARBADOS. JULY 20, 1912. 



PsiCB Id. 



CONTENTS. 



I^liiiciill mo ill .S(. Vin- 

 cuiil, 1910-11 



Black Blis,'ht in Grenadji 



C;iiii|ilior fimu Dried Cam- 

 phor Loaves 



Cliloio-is, I'Jxperiineiitsini 



Uocton Notes : — 



West Indian Cotton ... 



Diiininica, Exjinits from 



Dominica, Victoria ftlus- 

 eum 



Fungus Notes : — 



A Bud Disease of tlie 

 Coco-nut Palm in 

 Mexico 



Fiintumia Kubbor in 

 Southern Nigeria ... 



Gleanings 



Guayiile Kublier Plant, 

 oil from 



Insect Notes : — 



A New Pest of Cow- 

 peas 



The Brown Hard-back 



The Cane Fly in Marti- 



nique 



IVIaiina Plant 



Pagb. 

 ,.. 240 



.. 238 



Pagk. 



Market Reports ... . 

 239 I Milk. Pastourizationof . 

 233 Mulberry and the West 



Indies 239 



229 I Natuie Teaching and Hy- 

 233 ' gione in British Gui- 

 ana Schools 232 



2;i0 Notes and Comments ... 232 

 228 Oil-yioldin'4 f'lant, A 



"Little known 229 



233 Oils, Vo<;etable, Work 



Doahng with 231 



Porto Rito University 



Agricultural College 237 

 Rock Phosphate, Avail- 

 ability of 231 



Rubber-Growing in Su- 

 matra 233 



Rulibor < liitput of Malay.i 230 

 Soil Fertility, Theories 



Concorning, 11 225 



Students' Corner 237 



Sugar Industry : — 



Suuar Manufacture in 



Java, 1910 227 



Vanilla Preparation in 



Sevoholles 228 



238 



23.T 

 236 



232 



234 

 234 



234 



227 



Theories Concerning Soil Fertility. 



IL 



'HE last article on this subject, contained in 

 'the previous issue of the Aijricultural Neivs, 

 [s,a.\-e an account of the theories concerning 

 soil fertility that have been advanced by Whitney and 

 others, of the United States Department of Agri- 

 culture. Before proceedincr to an .n -count of Russell's 

 criticism of these;* it will be convenient to give 

 broadly his summary of the hypotheses presented 



♦ .'sVieine Pi ogress. Vol. VI, N... 21, !■. 142. 



in that article. They are concerned with the following 

 matters: (1) soils result from the breaking-up of rock- 

 forming minerals, the extent of the decomposition that 

 lakes place being very small: (2) the result is that 

 all normal soils possess a similar chemical composition 

 and contain a soil solution of the same constitution; 

 (.S) but as this solution is the nutrient solution for 

 plants, the amounts of plant food provided in all soils 

 are very similar; (4) this soil solution is distributed 

 over the soil particles, and the way in which certain 

 properties of the particles allow it to travel over them, 

 through the soil, is of the greatest importance in rela- 

 tion to the productivity of soils; (5) some other circum- 

 stance must also be active, in many cases, in regulating 

 this productivity, for some soils which are themselves 

 infertile give watery extracts in which plants cannot 

 grow, so that a toxin must be present in such soils; 

 (fj) the origin of such toxins may be the normal 

 decomposition of organic matter in the soil, but some 

 are probably given off by the roots of plants; lastl}' 

 (7) manures are not mere sources of plant food, but act 

 favourably in the soil in a complex way depending on 

 their power to alter the distribution of the soil solution 

 or to prevent the action of some of the toxins, and 

 jirobably in other ways as well. 



It had been long recognized that the fertility of 

 soils depends in a very intimate way on their physical 

 condition, but the first papers-'-of Whitney were 

 instrumental in putting forward clear and definite ideas 

 in the subject; while other investigations showed the 

 connexion between the properties of soils and those of 

 the particles composing thein. The ultimate result was 

 that the mechanical analysis of soils reached its present 



tUnited States Weather Bureau, Bulletin No. 4; United 

 States Department of Agriculture, Division of Soils, Bulletin 

 No. 13. 



