304 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



introductions, and the plantings of this grass have been considerably 

 extended. At the Glenwood substation large yields of honohono 

 have been secured as a soiling crop for dairy cows, and the practica- 

 bility of the use of cane tops for silage has been fully demonstrated. 

 The silage kejDt well and was relished by cattle. 



The station continues to distribute valuable seeds and plants 

 throughout the islands, and during the year many thousands of 

 cuttings of hibiscus hybrids were sent out for planting as ornamental 

 hedges, a large proportion of them going to Fort Shafter and Scho- 

 field Barracks for the ornamentation of their grounds. Variety tests 

 of different agricultural and horticultural crops and experiments in 

 the best methods of handling them are in progress at the station, the 

 results of which will be disseminated widely through the extension 

 and demonstration service. 



As a result of preliminary investigations by several members of 

 the station staff, the practicability of the use of arsenite of soda for 

 the suppression of weeds, especially in pineapple and cane fields, has 

 been definitely established. 



PORTO RICO STATION. 



During the past fiscal year the activities of the station have been 

 continued along the principal lines enumerated in previous reports. 

 The new plant house erected from insular funds has been put in use 

 and valuable results have already been secured through this agency. 

 The analytical and plat work conducted by the chemist and assistant 

 chemist have been considerably extended. The experiments with 

 sugar cane on red clay soils that included the study of more than 300 

 plats have been brought to a close and the results are being prepared 

 for publication. As a result of the investigations of the station it is 

 now possible to give definite information regarding the fertilizing of 

 the cane crops on this type of soil. The survey of the island for 

 deposits of bat guanos has been continued, and more than 40 caves 

 have been explored. About 150 samples of bat guanos have been 

 analyzed in the laboratory. These samples run from 5 to 30 per cent 

 phosphoric acid and from 0.025 to 8 per cent nitrogen. Vegetation 

 experiments are in progress to determine the availability of this 

 phosphoric acid. The chemical work on lime-induced chlorosis has 

 been continued, the investigations including studies on the iron nutri- 

 tion of rice, selective absorption by the roots of plants, and the com- 

 position of the ash of rice at different stages of growth. 



The cooperative work in the fertilization of citrus orchards has 

 been brought to a close and the results published. It was found that 

 nitrogen was the limiting factor in all cases, with phosphoric acid 

 next in importance. For the lighter rolling lands on the northern 

 coast a complete fertilizer gave the best results. In a similar way 

 experiments have shown that nitrogen was the important lacking ele- 

 ment required for the more profitable production of coffee and cane. 

 Field experiments showed largely increased yields where fertilizers 

 have been properly used. In connection with the improvement of 

 the soil, extensive experiments have been conducted with leguminous 

 cover crops, and a number of introduced as well as some native spe- 

 cies have been found well adapted to the purpose. Some of the most 



