310 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



loss of the sales funds and no increase in the appropriation made 

 impossible some desirable extensions of the work. A number of 

 projects that have been in progress for several years were completed, 

 and the results are being prepared for publication. 



One of the nlajor investigations conducted by the station is the 

 improvement of Porto Rican soils. This problem has been ap- 

 proached from several different points. The use of leguminous 

 plants in restoring the fertility of orchard soils has been investi- 

 gated, and a bulletin giving some of the results obtained was issued 

 during the year. The station is continuing its investigations with 

 many kinds of leguminous plants, some of which occupy the soil for 

 but a few months, as in the case of cowpeas, or for many years, as 

 with certain tree species. The survey of the guano caves of the 

 islands was continued, and 103 were surveyed, mapped out, and esti- 

 mates made of the amount of available fertilizer. This work has 

 been supplemented by laboratory analyses and pot tests to determine 

 the availability of the fertilizer constituents. Some studies were 

 begun of the mother liquor from salt works as a possible source of 

 potash, and a survey of the phosphate deposits on Mona Island is 

 contemplated. The availability of the different phosphatic fertilizers 

 for various Porto Rican soils is now being studied. A beginning has 

 been made of a soil survey, combined with a series of field experi- 

 ments. All these will be extended as rapidly as funds are available. 



The technical investigations on the absorption of iron by the rice 

 plant and the selective absorption by plant roots were about con- 

 cluded. A study was made of colorimetric methods for the esti- 

 mation of iron in plant ash and the results will soon be ready for 

 publication. 



Cooperative experiments with the insular government have been 

 in progress for several years with fiber plants and a number of 

 cordage fiber plants were brought to maturity and given a pre- 

 liminary test. Before much further work is possible in this line a 

 decorticating machine is necessary to determine the economic value of 

 the different species. Hat weaving is an important minor industry, 

 hats valued at more than $500,000 having been exported during the 

 past year. The station is contributing to its development by the in- 

 troduction of the jipi japa palm (Carludovica palmata) from which 

 the true Panama hats are made. This plant is being propagated and 

 distributed as rapidly as possible. 



In horticulture, the station is paying especial attention to the pro- 

 pagation of the better varieties of mangoes and has begun some 

 shipping and storage experiments with the fruits. The fertilizer 

 experiments with coconuts have been carried on for a sufficient time 

 to show that green manures and commercial fertilizers can be very 

 profitably utilized with this crop. The first crop of station-grown 

 vanilla was sold last summer at $2.50 per pound. Cuttings of vanilla 

 are being distributed as rapidly as possible and as this plant is 

 adapted to the same conditions as coffee, the production of vanilla 

 should soon develop into an important industry. The work with 

 coffee, in which higher yielding coffees of good quality are obtained 

 by selection or otherwise, continues to be highly successful, and 

 planting of these varieties is becoming quite general over the island. 

 Fertilizer experiments have shown that a light application of readily 



