20 FARMERS' BULLETIN. 



picul of cured seeds harvested. These 37 kilos of plant food that are an- 

 nually taken from each hectare may be roughly subdivided as follows : 

 18 kilos of nitrogen, 

 10 kilos of potash, 

 9 kilos of phosphoric acid. 



On this basis, after the plantation is in full bearing, we would have to 

 make good with standard fertilizers each year for each hectare about "220 

 kilos of nitrate of soda, or, if the plantation was shaded with leguminous 

 trees, only one-half that amount, or 110 kilos. Of potash salts, say the 

 sulphate, only one-half that amount, or 55 kilos, if the plantation was un- 

 shaded. If, however, it was shaded, as the leguminous trees are all heavy 

 feeders of potash, we would have to double the amount and use 110 kilos. 



In any case, as fixed nitrogen always represents a cost quite double that 

 of potash, from an economical standpoint the planter is still the gainer 

 who supplies potash to the shade trees. There still remains phosphoric 

 acid, which, in the form of the best superphosphate of lime, would re- 

 quire 55 kilos for unshaded orchards, and about 70 if dap-dap, Pionciana, 

 or any leguminous tree was grown in the orchard. These three ingre- 

 dients may be thoroughly incorr>orated and used as a top dressing and 

 lightly harrowed in about each tree. 



If the commercial nitrates can not be readily obtained, then recourse 

 must be had to the sparing use of farm manures. Until the bearing age 

 these may be used freely, but after that with caution and discrimination. 

 Although I have seen trees here that have been bearing continuously for 

 twenty-two years, I have been unable to find so much as one that to the 

 knowledge of the oldest resident has ever been fertilized in any way, yet, 

 notwithstanding our lack of knowledge of local conditions, it seems per- 

 fectly safe to predicate that liberal manuring with stable manure or 

 highly ammoniated fertilizers would insure a rank, succulent growth 

 that is always prejudicial to the best and heaviest fruit production. In 

 this I am opposed to Professor Hart, 1 who seems to think that stable ma- 

 nures are those only that may be used with a free hand. 



We have many safe ways of applying nitrogen through the medium of 

 various catch crops of pulse or beans, with the cejtainty that we can never 

 overload the soil with more than the adjacent tree roots can take up and 

 thoroughly assimilate. When the time comes that the orchard so shades 

 the ground that crops can no longer be grown between the rows, then, in 

 preference to stable manures I would recommend cotton-seed cake or 

 "poonac," the latter being always obtainable in this Archipelago. 



While the most desirable form in which potash can be applied is in the 

 form of the sulphate, excellent results have been had with the use of 

 Kainit or Stassfurth salts, and as a still more available substitute, wood 

 ashes is suggested. When forest lands are near, the underbrush may be 



1 "Cacao," p. 16. 



