127 



for mulching when about to flower. In this way there would 'only 

 be the preliminary expense of establishing the herbaceous perennial, 

 and the small expense afterwards of cutting it down. Quantities of 

 valuable food material would thus be brought up from the subsoil, and 

 deposited in the mulch on the surface to decay for the benefit of the 

 cocoa, coffee, or other plant. 



NOTES ON PHOSPHATE MANURES. 



BY 



H. H. Cousins. 



Apart from the material question of cost, I have always advocated 

 that planters would be well-advised to avoid the complete fertiliser 

 and the special manure of commerce and to purchase the special ingre- 

 dients required at current market rates. ^.^^ 



Our experience in the purchase of fertilisers for the Manurial Ex- 

 periments of the Board of Agriculture indicate that there is a saving 

 of quite 25 o/o in cost, apart from the special advant;iges arising from 

 adjusting a manurial mixture to the needs of particular soils and crops. 



My chief objection to the ordinary ' complete' manure of commerce 

 lies in the fact that there are three types of phosphatic fertilisers, each 

 peculiarly suited to a particular type of soil. It is quite possible to 

 use each of these forms of phosphoric acid without any reasonable pro- 

 bability of any benefit and a possibility of a depression in the result- 

 ing crop. For example : Basic Slag is frequently absolutely inopera- 

 tive on calcareous soils, while superphosphate may result in detriment 

 to the crop if applied to soils deficient in Carbonate of Lime. Again 

 there are some soils, representing the lighter lands of our fertile allu- 

 vial tracts in Jamaica, where Basic Slag would be inoperative, super- 

 phosphate injurious and an intermediate or mixed phosphate be the 

 form best adopted to the nature of the soil. 



To use a " complete manure," containing in the majority of cases 

 acid phosphates, indiscrimiuately on all our Jamaica soils is, to my 

 mind, a chemical absurdity. 



Before purchasing manures, planters would do well to consult 

 the chemist and avoid paying too high a price and the possibility of 

 getting an unsuitable mixture. 



On many soils in Jamaica Phosphates are quite unnecessary. 

 Analyses show that most of our good land is very rich indeed in this 

 ingredient and that when exhaustion takes place in course of time, fer- 

 tilisers supplying Nitrogen and Potash only should suffice to maintain 

 the standard of fertility in these cases. 



Appended ai-e some data as to phosphatic fertilisers recently im- 

 ported into Jamaica which may serve to guide planters as to a w ise 

 selection. 



