I 



1154 EXPERIMENT] STATION RECORD. 



HOMjiCTJLTTJitE. 



Pineapple culture. Ill, Fertilizer experiments, H. K. Miller and A. W. 



Blair {Florida Sta. Bui. 83, pp. 405&37, pis. 8, dgms. 3).— This bulletin contains 

 the detailed plan and results of fertilizer experiments with pineapples, extendino 

 over a period of 5 years. 



The purpose of the experiment was ' to find out from what source or sources iris 

 best to obtain fertilizing materials for j ineapples; the proper quantity to use for the 

 best results as regards quantity, qualify, and shipping properties; best method of 

 applying; ratio of phosphoric acid, nitrogen, and potash; the effect of shading, and 

 to determine any other conditions which will prove of advantage to the industry." 



The experiment contained 96 separate plats, with as many variations and combina- 

 tions of the fertilizers commonly used for this crop. Each plat contained 100 plants 

 and occupied t Aq of an acre. All the plats were covered with a lath shed, furnish- 

 ing | shade. Preliminary to the work pineapples were analyzed with reference to 

 the fertilizer constituents contained to determine the proportion in which they exist 

 normally in the plant and fruit. The ratio of the constituents was found to be prac- 

 tically as follows: Phosphoric acid 0.8, nitrogen 1, and potash 2. The results secured 

 on the different sections of the plats are discussed in considerable detail and illustra- 

 tions given of the plants on many of the different plats. 



Acid phosphate was found to have an injurious effect upon pineapples which 

 could be corrected by the use of lime. It is thought that the acid phosphate itself 

 was not the cause of the injury, but rather the sulphate of iron and aluminum which 

 it contained, since acid phosphate derived from bone black did not have any inju- 

 rious effect on the plants. Since, however, acid phosphate is occasionally colored to 

 represent dissolved bone black, it is recommended that one not experienced in the 

 use of fertilizers should not use any form of acid phosphate whatever for pine- 

 apples, but rely upon bone meal or slag. 



On the whole the best results have been obtained by the use of about 3,750 lbs. per 

 acre of fertilizer, analyzing 4 per cent available phosphoric acid, 5 per cent nitrogen, 

 and 10 per cent potash, and this formula was perhaps best compounded by the use 

 of bone, blood, and high-grade sulphate. 



A number of fruits were analyzed to see if increasing amounts of fertilizer would 

 affect their composition. The results obtained are tabulated, but the data are not 

 considered sufficiently satisfactory to warrant conclusions. 



Among the recommendations and conclusions drawn from the whole work, it is 

 shown that as a source of phosphoric acid fine ground steamed bone, bone meal, and 

 slag have given the best results. If acid phosphate is used lime should be added 

 every year or two at the rate of 750 lbs. to the acre. "As sources of nitrogen, 

 dried blood, cotton-seed meal, and castor pomace may be used. Nitrate of soda may 

 be used for the first 6 months and possibly, to a limited extent, for the first year, 

 but after the first year it will probably be safer to eliminate it entirely. Consider- 

 able caution is required in its use. 



' ' Of the potash salts used, high and low grade sulphate have given the best results, 

 the latter seeming slightly the better. Muriate has given fair results, though the 

 sulphate undoubtedly gives better results. Kainit should not be used. High-grade 

 tobacco stems, though not used in this experiment, have been used by a number of 

 growers with good results. 



"For most of the east coast soils we would recommend 3,500 to 4,000 lbs. to the 

 acre annually of a fertilizer analyzing 4 per cent available phosphoric acid, 5 per 

 cent nitrogen, and 10 per cent potash, to be applied at the rate of four applications a 

 year for the first 18 months, and after this two applications a year; one in February 

 or March, as the conditions may require, and one soon after the removal of the sum- 

 mer crop." 



