24 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



Some attention has been given to methods of grinding algaroba 

 pods in order that the hard seeds shoidd be crushed and their protein 

 not lost in feeding. Through the cooperation of a skilled mechanic 

 a machine has been devised that grinds these pods, and it is probable 

 that its use will greatly add to the available nutritive value of the 

 algaroba beans, which are used as stcx'k feed in large amount. 



On account of the presence of perennial weeds, various means for 

 their control have been investigated, and the use of carbon bisulphid 

 was found to successfully destroy herbaceous and shrubby weeds. 

 The application of a small portion of the chemical to the stems 

 3'esults in the death of the plant within a period varying from a 

 few hours to several weeks. 



In addition to these investigations, the station has in progress 

 rotation and cultural experiments with a large number of tropical 

 crops. 



PORTO RICO STATION. 



The experiment station in Porto Rico has made substantial prog- 

 ress with its work and investigations during the past year. "Wliile 

 the opportunity for work at a tropical experiment station is very 

 great, nearly every line of agriculture requiring investigation, the 

 Porto Rico Station has very properly concentrated its efforts on a 

 few definite lines. The agricultural conditions of Porto Rico are im- 

 proving, and as more modern methods are being adopted the planters 

 of the island are calling upon the station for more a,nd more assist- 

 ance. These are responded to as far as possible, and the station seeks 

 by every means to bring the results of its investigations before the 

 people. When the proposed agricultural college is established and 

 equipped much of this w'ork Avill be turned over to the new institu- 

 tion, relieving the station of a great deal of the elementary and 

 demonstration work and permitting more time to be devoted to in- 

 vestigations. Considerable cooperative work is being carried on 

 with various planters in testing new varieties of economic plants, 

 fertilizer tests with various crops and soils, shipping experiments 

 with tropical fruits, and similar work. Some of the leading results 

 of the past year's work are presented below. 



The physiologist has made an especial study of the so-called tired 

 or sick soils. These soils w'hile apparently fertile, so far as chemical 

 analysis will show, do not produce profitable crops. Studies were 

 made of a considerable number of coffee, pineapple, and cane soils, 

 and in all cases where there was trouble the soils were found to 

 contain a great excess of butyric acid. Associated wnth this acid 

 were a number of bacteria, which develop rapidly in soils when roots 

 or other organic matter containing sugar and starch are present. 

 Through the fermentative activity of these organisms butyric acid 



