752 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



During the year the agronomist visited Japan for the purpose of 

 studying (he rire iiuhistry and ahoiit mO varieties of Japanese rice 

 Avere obtained for introduction into Hawaii. Four of these are con- 

 sidered particuhirly vahuible, and it is hoped that from these there 

 may be developed a sui)ply of rice suited to the re(iuirements of the 

 Japanese popuhition of the ishinds. Extensive fertilizer experi- 

 ments with rice have been carried on, and it has been demonstrated 

 that the proper time to apply fertilizers for rice is before planting 

 and not with the irrigation water during the growth of the plant, as 

 has been the practice. The rice plant was found to take up its plant 

 food early in its growth and the stooling or tillering was greatly 

 increased by the early application of the fertilizers. It has also 

 been found that ammonium sulphate is a better source of nitrogen 

 for rice in Hawaii than sodium nitrate; in fact, there appears to be 

 some evidence that the rice plant, especially when submerged, does 

 not use the nitrates directly. 



Attention is being given to corn breeding, and selection experi- 

 ments are in progress to obtain the best varieties for Hawaiian 

 conditions. 



Through the influence of the station there is considerable interest 

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

 IMgeon peas, cowpeas, and jack beans are being extensively grown, 

 the pigeon pea and jack bean doing exceedingly well. Cowpeas are 

 subject to attacks of plant lice, but where these pests have been 

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

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

 cialh' wdiere pineapples are grown. An experiment with sugar cane 

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

 some conditions. 



The station chemist has 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. Further experiments have 

 shown that where manganese is present in considerable quantity the 

 cultivation of pineapples should be discontinued and less susceptible 

 crops grown in their stead. Where less quantities of manganese are 

 found in the soil the addition of fertilizers composed of superphos- 

 phates, 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 pine- 

 apple 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. Preliminary experiments have shown the value of drainage 

 in increasing the aeration of the soil. A study of the ripening proc- 

 esses 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 

 pipeapple has led to investigations which have shown methods 

 w^hereby they can be profitabW utilized. 



The horticulturist has about perfected methods for the propaga- 

 tion of the mango and avocado, and attempts are being made to secure 



