24 EEPOKT OF OFFICE OF HXPERIMENT STATIONS. 



that Egyptian cotton can be added to the types grown in Hawaii. 

 In experiments on the use of fertilizers for cotton, tlie value of phos- 

 phates in increasing production has befen clearly shown, increases of 

 two or three fold over check plats being obtained. 



Attention is being given to corn breeding, broom corn, etc. 

 Through the influence of the station there is considerable interest 

 in the growing of leguminous plants for cover crops and for forage. 

 Pigeon peas, cowpeas, and jack beans are being extensively gTown, 

 the i^igeon pea and jack bean doing exceedingly well. Cowpeas are 

 subject to attacks of j^lant lice, but where these pests have been 

 absent the crop has been one of the best. The success attained with 

 leguminous jjlants has led to the adoption of rotation of crops, espe- 

 cially where pineajoples are grown. An experiment with sugar cane 

 has also shown that rotation for this crop is profitable, at least under 

 some conditions. A fertilizer experiment on a plantation that has 

 been in taro for fully 200 years was begun, and an opportunity will 

 thus be given to determine the fertilizer requirements of this crop. 



The station chemist continued his pineapple investigations, the 

 studies including the effect of manganese on the plant, the process of 

 ripening of the fruit, and the utilization of the by-products from 

 the canneries. The injurious influence of manganese on pineapples 

 has been mentioned in previous reports. Studies were undertaken 

 to ascertain what crops, if any, could be grown in rotation with 

 pineapples or to replace them on manganiferous soils, but with little 

 promise of success. Where less quantities of manganese are found 

 in the soil, the addition of fertilizers composed of superphosphates, 

 sulphate of ammonia, and sulphate of potash will overcome the 

 injurious effect to a considerable extent. These investigations have 

 led to the discovery that the most serious drawback to pineapple 

 culture in Hawaii is a lack of proper aeration of the soil. The soils 

 contain large amounts of iron, and as a result they are easily puddled 

 after a rain or irrigation and air can not penetrate to the roots. Pre- 

 liminary experiments have shown the value of drainage in increasing 

 the aeration of the soil. A study of the ripening processes of the 

 pineapple has shown that the sugar content of the fruit is directly 

 influenced by the degree of ripeness when cut, there being no increase 

 after the cutting of the fruit, although a green fruit may turn yellow 

 and become soft. The large waste of materials about the pineapple 

 has led to investigations which have shown methods whereby they 

 can be profitably utilized. 



The horticultural investigations were continued along previous 

 lines, the attempt being made to induce a more general growing of 

 improved varieties of tropical fruits. Satisfactory progress was 

 made in propagating mangoes and avocados, and the method for 

 mango propagation described in the previous report of the station 



