Vol. IX. No. 223. 



THE AGRICULTURAL NEWS. 



3f)l 



The Trade of Gambia 1 909. 



Information concerning the trade of this colony is 

 given in the Gamhia Government Gttie^^efor August 3, 

 1910. This shows that the e.xports of the chief 

 products during 1909 had the following \alues: ground 

 nuts £323.231, hides £.S,.")20, palm kernels £3,52(i, wax 

 £2,180, rubber £1,5.50. 



The crop of ground nuts was a record om-, the 

 quantity exported being .>i,i>44 tons, as compared 

 with 31,961 tons in 1908. The cmmencement of this 

 trade was on account of the demand for ground nuts 

 in the United Kingdom and the Uniti-d States; but the 

 product is now almost entirely ex|)orted to France. 

 Attempts are being made, however, to increa.se the 

 trade with the United Kingdom. 



production of butyric acid, .so that p irlial disinfection 

 by sunlight, or by carbon bisuljihide is the remedy 

 recommended for sick soib. 



The 'Sick' Soils of Porto Rico 



It has long been known that cirtain soils, t\en 

 when they are in receipt of a ph-ntiful supply of manure, 

 gradually lose their power to produce good crops. The 

 terms ' sick' and ' tired' have been used to describe 

 a condition for which satisfactory ex])lanati(jns have 

 onlv been found recenth". It has been demonstrated 

 tiiat apparent soil sickness is dne either to the presence 

 of pests, such as eel-worms, on the roots, or to the 

 existence of conditions in the soil itself which are 

 inimical to the growth of plants. It is the latter state, 

 i.nlv, that can be ileicribed correctly as soil sickness. 



The circumstances of soils in w hich these conditions 

 have arisen receive attention in t'ircuiar No. 12 of the 

 Porto Rico Agi-icultural Experiment Station, entitled 

 (hi the Sirk' Soils of Porto Rico. It is pointed our, 

 first of all. in this publication, that sick soils cannot 

 be made fertile by ai)plications of manure: this is 

 t;he chief characteristic which .serves ti> distinguisli them 

 from 'worn out' or exhausted soils. A predisjio.sing 

 cause of sickness is the continual ajjjjlication of organic 

 manures that have not been previously rotted; common 

 examples of such manures are, as is stated in the Cir- 

 cular, tankage, dried bl 1, eottoii seed meal and fresh 



pen manure. The use of these, yeai- after year, on the 

 same soil, causes an increase of certain fungi and bac- 

 teria in it, which feed on the organic matter, and by 

 fermentation, convert it into formic, acetic, butyric, or 

 other injurious acids. It is in heavy, badlyaerated s.iils 

 that these are specially found, and their numbers are 

 naturally greatest near the surface of dead and living 

 roots. S'ot only the harmful acids mentioned .ire ]iro- 

 duced, but jmisons of a different naturf . such as sulphur- 

 etted hydrogen, and other, more complex, bodies. 



It is a curious fact that the investigations with 

 sick soils in Poito Rico showed that little damage was 

 suffered by them through the action of denitrifying 

 organisms. The harm was found to be caused by an 

 unwonted increase in the numbers of the butyric 

 organism {Clostridium pastorianum). This is a nitro- 

 gen gatherer: but the good that it might do through 

 the possession of this property, when it is present m 

 any ninnbers, is more than counterbalanced by its 



The Requisites in Paper-Making Material. 



In an article, dealing with the ijuestion of suitable 

 tibres for paper-making, which nppeared in the Paper 

 Trade Review for March 11. 1910, a list of tests is 

 given which should be applied to fibrous material, and 

 to the conditions surrounding its production, in order 

 that the suitability for the purpose may be determined. 

 These refer to products that are being raised or em- 

 ployed in the special connexion, and one of the most 

 important among them is that the material cannot be 

 employed in any other economic direction. It must be 

 reproduced naturally, and not easily exhausted through 

 regular collection. As regards its production, little 

 cultivation must be needed, and the time it takes to 

 attain maturity must have a suitable relation to the 

 rate of its required sup})ly; in addition, its habit must 

 be gregarious, and it must occur sufhciently abundantly 

 to enable the cutting and collection of it to be effected 

 chea])ly. As regards the last matter, it is evident that 

 it must grow in a locality where laliour is cheap. 



Finally, as regards the retpusites more closely 

 connected with manufacture, the total quantity avail- 

 able, within economic collecting distance from the mill, 

 must be sufficient to produce at least 2-5.000 tons of 

 pulp annually, and the material should contain at 

 least 30 per cent, of cellulose. 



Catch Crops in Lime Cultivation. 



Varying results ha\e been i>btained. under difFer- 

 inc- conditions, when the employment of catch crops 

 during the first two or three years of the growth of lime 

 trees has been attempted. It is interesting to note, in 

 this connexion, the results that have been obtained at 

 the Onderneeming School Farm, British Guiana; these 

 are described in the annual report on that institution for 

 1909-10. The original purpose of the experiment was 

 to afford a demonstration as to the comparative ease 

 with which permanent cultivations of limes may be 

 established, without the entailment of any serious inter- 

 ference with the crops of ground provisions that are 

 being raised on the land. 



In the exjierinient, lime seedlings were planted, 

 three years ago, in a .small 2-acre held, plantains and 

 cassava being grown at the same time. Entirely satis- 

 factorv results were obtained, for the yield from the 

 food ero]>s was good, and the lime trees made vigorous 

 growth; so that on the discontinuation of the raising of 

 the catch cro]is, a lime field has been obtained which 

 presents a model appearance. 



In continuation of the object-lesson, other areas 

 are being treated in the same way, the catch crops 

 being corn, jilantaiiis, eddos, tanias and similar plants, 

 while, where the soil is sandy <md less fertile, cocoa- 

 nuts have been planted at proper distances, and sweet 

 potatos are being raised at yjresent, as well. 



