. 146 



-tent of nitrogen and this can bnW attain a high standard where the 

 .deposit is protected from the action of rain and of excessive moisture. 

 Samples below 2 ^ of Nitrogen could scarcely be handled economically 

 in Jamaica for local sale. For export a minimum of at least 6 9^ of 

 Nitrogen would be necessary to cover expenses and make the sales re- 

 munerative to the owner of the deposit 



Sample 29 represents a deposit that has been freely washed by rain. 

 It contains no more nitrogen than an average Jamaica soil, while the 

 Phosphoric Acid is not sufficiently high to warrant its use as a source 

 «f Phosphates. No. 31 (from St. Thomas) represents a large deposit of 

 high class Bat-guano that has been found to be an excellent fertiliser 

 for sugar cane. This was valued at £4 per ton to the buyer allowing 

 for 25 Yo latitude. 



Samples 32-35 are the successive layers of a large cave deposit in St. 

 Catherine of which No. 32 is the upper and richer layer. The amount 

 of moisture in these deposits is, for export, excessive and should be re- 

 duced to 10 ^ by drying the material in the sun. A saving of 25 96 

 in the bulk of the material could then be effected. Owners of caves 

 are warned not to base their calculations upon the analysis of the top- 

 layer only, since a gradational loss in nitrogenous materials is to be 

 expected as the deeper layers of the deposit are drawn upon. In the 

 case mentioned above the owner decided not to ship the deposit but to 

 seek a local market for it. 



Bat-Guano is, as the average figures show, a fairly well balanced 

 manure. The better samples are principally nitrogenous in character. 

 Considering the richness of many Jamaican soils in Phosphoric Acid, a 

 good grade of Bat-Gruano should prove an excellent fertiliser for Sugar 

 Cane or Bananas ; on some soils it would be well to fortify it with Potash 

 salts. In valuing a Bat Guano, I would suggest 9s. for each per cent. 

 .of Nitr 'gen per ton, 3s. for each per cent of Phosphoric Acid and 4s. 

 for each per cent, of Potash per ton. 



Thus sample 32 would be valued as follows : 



Nitrogen 8-8 per cent at 9s. = 79s. Od 



Phosphoric Acid 2-2 per cent at 3s. = 6s. 6d. 



Potash 5 per cent at 4s. ^ 2s. 



Total 87s. 6d 



The "aveiagt" of all the samples iiives the following valuation 

 Nitrogen 4*5 per cent ut Ws. = 4Us. 6d. 



Phosphoric Acid 5'3 per cent ut 3s. = 16s. 



Potash 1-3 per cent at 4s. = 5s. 



Value per Ton 61s. 6d 



This estimate is based upon the current unit values of fertilisers deli- 

 vered free ai Kingston. I have deducted 25 per cent from the valua-^ 

 tion of the Nitrogen to allow for 'latitude' or variability in the samples 

 and for the inert properties of some of the nitrogenous constituents. 

 These values represent what, in my opinion, a planter would be 

 justified in paying for a Bat-Guano for use on his estate. 



