A FORTNIGHTLY REVIEW 



OF THE 



IMPERIAL DEPARTMENT OF AGRICULTURE FOR THE WEST INDIES. 



UKK 



HEW 



Vol. XIV. No. 354. 



BARBADOS, NOVEMBER 20, 1915. 



Price Id. 



CONTENTS. 



Page. 



Page. 



I- . Shelf 375 



I i iera1 ive < Iredil Si i 



ties in England, Need 



_ for ."77 



Colour and Poison in the 



Lima Bean 373 



i Notes 



Wesl Indian Cotton ... .'.74 

 Departmental Reports ... 381 

 I diseases of Plants: — 



Nen Light .if tin- Witch- 



Br i Disease ..t' 



1 "in 382 



Foresl Soils and Nitrogen .'Ki'.i 



Gleanings " ... : :.si » 



' ' Population in 



i i ovi n ( lolonies and Pro 



tectorates :'.7. s 



Insei V 



The Control of Am- 

 which Take A.waj 



1 'in. 'ii Seed :\7* 



Items ol Local Interest ... 383 



Lime i 'nil n a1 ion 372 



Manui i.il Experiments in 



Boxes 371 



Market Reports 



Notes and Comments ... 

 ( Grange TradeDifficultj , < ><u 

 ! its and Pigeon Peaa 



for Export 



I 'eppei . Impro\ ing the 



Chile 



Pine-apples for ('ana. In... 

 Plant Br< edihg in Maiy- 



land 



Pi-ess, A Continuous ... 

 Rubber and Coco nuts in 



t he St raits Settlements 

 Rubber Track, and Wai 



i londil ions 



Soil Analysis 



Soil, Temperature of, 



Under Different < !ondi- 



i s 



Sour < trass, Varieties of .. 

 Industry: 



The 1914 .lava Sugai 



Cro 



I he I i-ansfusion of Sap... 

 Vanilla Supports in St. 



\' in. .nt 



384 

 37C 

 376 



:;,si 

 :;7'.i 



376 



■ "■71 



:;7'.t 

 :;,si 



::7I 

 :;7." 



381 



Forest Soils and Nitrogen. 



'HE usual practice is to classify soils crudely 

 Laccording to their chemical and physical 



Li iposition, bul we can often gel a better 



idea of their constitution and requirements l.\ consid 

 ering them in relation to tin- kind nt' crops they bear. 

 In tin' tropics this is particularly so where r wide 

 nt' soils occurs between the two extremes ol 

 desert ami dense forest. Speaking generally, it is not 

 'I,, soil particles S" much as tin- heat and the rainfall 

 as will as the aspect, including physical conformations, 



that determine the most important features of a soil's 

 fertility, because these factors decide what plants can 

 grow there, [fthe rainfall is heavy, the natural cover- 

 ing will be forest, ami as a result of vegetable decay 

 the underlying soil will be rich in humus, and will 

 exhibit certain well-marked bacterial characteristics. 

 This soil is the natural medium of growth for such 

 trees as cacao and rubber, and becomes ultimate!) 

 what; we have conic to call an orchard soil. On the 

 other hand, soils which are more exposed to wind and 

 sun, and which receive a lighter rainfall, tire inhabited 

 naturally by .a hardier type of vegetation, and these 

 are the soils which are ultimately brought under the 

 plough. Such soils ,is thi.se In ■< j uoi it lv exhibit greater 

 alkalinity and greater extremes of texture between 

 'heaviness' and 'lightness', and in the matter of colour, 

 than orchard soils, while the bacterial activity is also 

 different in many respects. 



It is our present object to consider what takes 

 place in an orchard sod that makes it different from 

 an arable soil, especially m respect of nitrogen supply. 



The form in which cacao and other orchard crops 

 obtain their nitrogen from the sod has been the subject 

 of speculation for some time. Knowing that the 

 supplies of free mineral bases such as lime, are 

 deficient in such soils, it has been suggested' that 

 ammonia formed in the process of ammonification may 

 function as a base lor the neutralization of nitric acid 

 formed during the later stages of nitrification, it is 

 well to bear in mind, however, that nitrification may 

 not be active in all on-hard soils: and that, moreover, 

 nitrifying organisms will not tolerate free ammonia." 

 Where nitric acid is absent it ma\ be supposed that the 



ami iia would combine with other acid radicles like 



Carbon dioxide or some of the organic acids, the 



