174 



THE TROPICAL AGRICULtURlST. 



[Sept. t, 18B6, 



myself on behalf of the Planters' Association, and 

 tne results are to be found on page 15 of my 

 official report. These analyses, however, deal only 

 with the organic constituents, and give the pro- 

 portions of oil, albuminous compounds, mucilage, 

 fibre, Ac, and do not afford information respecting 

 tlie chemical composition of tne mineral portion 

 or ash of the cake. I have therefore obtained a 

 fair average sample direct from India and hope 

 the particulars of tiie analyses may be of interest 

 to the readers of the 2\ A.: — 



In 100 parts of white castor cake : — 

 Waler 7-94 



InOrgauic matter (containing Nitro- 

 gen 7'5o) 85-17 



Jlineral matter* G-89 



• 10000 



It will be noticed from these results that while 

 castor cake is very rich in nitrogen, containing in- 

 deed twice as much of this valuable constituent 

 as ordinary bone dust, and five times as much as 

 would be found in 100 lb. of parchment coffee ; so 

 that the application of 100 lb. of this cake should 

 supply as much nitrogen as could be removed by 

 500 lb. of parchment coffee. Further, the mineral 

 portion (trSlI) is twice as much as I found in well- 

 prepared parchment coffee from the neighbourhood 

 of BaduUa (see page 110 of my report) which con- 

 tained 3'30 per cent of ash or mineral matter ; so 

 that as regards these constituents castor should 

 be well adapted to supply a very large portion of 

 the mineral constituents of coffee even supposing 

 the soil did not do so as is usually the case. 



Thus, in every 100 parts of cake I find 2-G8 of 

 phosphoric acid as against -^G in 100 parts of the 

 coffee and 1'35 of potash, against 1'34 in coffee 

 (which is practically the same), soda -07 against 

 •0(5, and, lastlj', \>0 of lime against 'Hi in coff'ee. 

 Castor cake yields an ash specially rich in phos- 

 phates of potash, lime and soda, and these exist 

 moreover in a form readily available as plant food 

 as fast as the cake becomes decomposed in the soil. 

 For comparison with the leaves of the coff'ee tree, 

 I may mention that in every 100 parts of partially 

 dried healthy leaves I found by analysis : — 

 Water ... ... ... 975 



Organic matter (coutaiuing Nitro- 

 gen 2-67) ... ... 82-65 



Mineral matter f ... ... 7-60 



7 09 



From these results it will be seen that coffee leaves, 

 are really far more exhausting to the land than 

 the parchment coffee, and if the tree can produce 

 plenty of leaf naturally, no manure should be 

 necessary in order to produce the coff'ee bean or 

 seed which in this case is certainly not an ex- 

 hausting crop. Planters know from sad experience 

 tlie baneful effect of wind and wash which strips 

 off' the leaves and hurries them off down to the 

 nearest stream. 



It is well however to remember that these leaves 

 if gathered green and made into composts with a 

 little lime, will furnish an excellent natural manure 

 as will readily be seen if the results of the above 

 analysis are compared with those of castor cake. 

 These leaves contained 2-67 of nitrogen or nearly 

 .^ of that in castor, while the lime 1-69 and potash 

 2-08 are both in considerable excess of that found 

 in the cake. In phosphoric acid however the leaves 

 are much poorer, there being only -35 against 2-08 

 in white castor which is certainly a most useful 

 cake for supplying phosphates as well as very 

 rich itt nitrogen. 



In looking out for valuable manuring materials 

 planters should therefore look well to the chemical 

 comjjosition of the sevenil substitutes for the grand 

 and universal manure namely farmyard-dung 

 which has been the only one employed to any 

 extent in ages past and which, as 

 general character, may be taken as a 

 to the planter abroad as well as to 

 at home. 



We must examine the composition 

 or mineral portion as well as the 

 nitrogen yielded by cakes and manures, for, as we 

 have seen in the case of white castor cake, every 

 100 lb. of the cake supplies 2-08 of phosphoric 

 acid which is equal to 5-85 lb. of phosphate of 

 lime or as much as would be found in 1,000 lb. 

 of parchment coffee. JOHN HUGHES, r.c.s. 



regards its 



safe guide 



the farmer 



of the ash 

 amount of 



The T. a. — I have always looked upon the Tropical 

 Afiriculturist as a " standard work," and as such 

 it is a book of reference to be placed on the 

 planter's book-shelf.— P^/H/er. 



Nitrification in Soils. — Dr. Taylor, Editor 

 of Science Gossij), in writing to the Melbourne Arf/iis 

 makes the following remarks on this important 

 subject : — 



Among agriculturists possessed of genuine scien- 

 tific tastes, there are few subjects regarded 

 with more interest than tiie relation of free nitro- 

 gen to soils. The discovery that nitrifictation in 

 soils was due to organisms whose activity can be 

 arrested by chloroform, so that no nitrification takes 

 place when their vitality is thus suspended, has 

 made the inquiry more interesting than ever. The 

 French chemists have always distinguished them- 

 selves in researches relating to this subject, as 

 everybody knows who has studied Professor Ville's 

 work on artificial manures. Recently the attention 

 of the French Academy has been directed to it. 

 Messrs. Bertholet and Andre have been at work 

 upon it for many years past. Lat(^ly they have 

 been concerned in finding out some means of in- 

 dicating the proportion of nilrificatory organisms in 

 different soils, and they conclude that some idea of 

 their abundance may be formed by a quantitative 

 analysis of the carbon entering into the constitu- 

 tion ' of their tisi^ues. It is inferred generally that 

 the analysis of the ammonia present in the soils 

 should be made without any dessicatlon, and that 

 arable land (when watered) tends continually to 

 liberate the anrmonia of the annnoniacal salta con- 

 tained in it. 



