'Vol. Xn. No. 296 



THE AGRICULTURAL NEWS. 



28.'5 



A YEAR'S WORK IN HAWAII. 



It is seldom that the investigation work conducted at 

 the Experiment Station in Hawaii lacks originality and fails 

 to serve a useful purpose. The truth of this remark is seen 

 in the reiiort on the Agricultural Experiment Station, 1912. 

 The lengthy summary of investigations carried on during 

 the year begins by giving an account of various improve- 

 ments introduced in regard to the buildings and the ground.s. 



INdENIODS IMPROVEMENTS. 



Two interesting innovation.s have been, first, a glass house 

 •constructed on pillars standing in water, which prevents the 

 entrance of ants; and the second, the provision of an 

 arrangement for providing bottom heat in the main prop- 

 agating bed by means of circulating water w'lich is heated 

 by sunlight in an outside tank. In regard to the grounds, 

 a useful measure has been the retention of 2 acres of 

 particularly dry land for employment in the testing of 

 drought-resistant qualities of certain grasses, fodder plants 

 and cottons. 



DEMONSTRATION FARMS. 



The station runs demonstration farms in order to 

 convince the planter as to the most satisfactory methods of 

 cultivation. Amongst other things they are shown, prac- 

 tically, the proper planting distance for bananas in different 

 localities; whilst in another place, particularly suited to 

 dairying, an equipment has been secured for demonstrating 

 the proper way to manufacture butter. In this connexion 

 it is hoped, in time, to bring the various dairymen together 

 for the purpose of ultimately establishing among them 

 a co-operative Jairy association. 



In the same way, the cultivation of rubber has been 

 brought systematically before the eyes of the planters. 

 Attention in this respect has been given principally to the 

 use of intercrops between rubber, and to the planting of 

 Ceara cuttings from the most heavily yielding trees. Con- 

 siderable work is being done in connexion with tapping, 

 ■whilst in regard to the preparation of Ceara rubber, it 

 ha.s been found that the impurities in the coagulum are 

 reduced in percentage, in proportion as the pressure is 

 increased between the rollers of the mangling machines. 



WOIiK ON FRl!IT FLIES ANP MOSQUITOES. 



Not less interesting are the entomological investigations 

 •arried on during the year. Efforts have been chiefly directed 

 to the study of the Mediterranean fruit fly, mosquitoes and 

 certain parasites, such as the cotton boll worm, algaroba bean 

 ■weevils, and scale insects. Practical work in combating the 

 first named pest has been carried on under the auspices of 

 the Territorial Government. In regard to mosquitoes, it has 

 been discovered that the yellow fever mosquito was much 

 less common than (Stegoniyia) Acdes scutularis, although the 

 latter species was apparently introduced into Hawaii later 

 than the yellow fever insect. Much useful information has 

 been collected with reference to the situation under which 

 the larvae breed. 



RE(;ULAT1N>; UNIFOIJMITY IN FRUIT. 



Studies have been continued as regards method,s of 

 propagating the avocado and the mango, and it has been 

 found that these fruit.^ may be inarched or budded alnio.st 

 with as much facility as is known to be the case with 

 fruit.s of temperate climates. Hence the difticulties which 

 had hitherto made the propagation of superior varieties 

 of avocados and mangoes uncertain, are rapidly disappear- 

 ing. Similarly, good work appears to have been done in 

 regard to the regulation of uniformity in Papayas. As 

 regards bananas, the shipment of these fruits to the 

 chief market in California is hampered by quarantine 

 restrictions, but it is hoped that the steamship companies 

 will arrange to carry the fruit without packing. This would 

 render inspection more effective and convenient. 



PINE-APPLES AND MANGANESE. 



Reference has been mude from time to time in this 

 journal to the chemical investigations conducted in Hawaii. 

 It may be remembered that one of the chief lines of work 

 carried on by the chemical department has been a study 

 of the function and the distribution of manganese in soils. 

 The work of the Station on manganese soils is lieing 

 closely followed by pine- apple growers. It appears im- 

 possible by any method so far adopted to grow pine- 

 apples successfully on soils which contain more than 

 2 per cent, of manganese: not only do the leaves turn 

 decidedly yellow or even whitish, but the fruits are pink 

 rather than of the normal colour, and are too acid or other- 

 wise disagreeable in flavour. In selecting new areas for the 

 extension of the pine-apple industry, prospective growers have 

 had the manganese determinations made in order to avoid 

 the areas in which a high percentage of manganese is found. 



A POSSIBLE REMEDY. 



Evidence is accumulating of the importance of 

 a reasonable balance between lime and magnesia in the soils 

 of Hawaii. Since the chief injurious effect of manganese 

 seems to be in causing plants to absorb too much lime and 

 too little magnesia, a systematic set of experiments has been 

 planned to determine whether the effects of manganese can 

 be overcome by adding magnesia to such soils. The results 

 of this work will be awaited with interest. 



A NEW FERTILIZER. 



A further very useful piece of research has revealed the 

 fact that the pulp of sisal hemp (which is usually thrown 

 away after the extraction of the fibre) is a valuable fertilizer. 

 Sisal removes large quantities of mineral plant food from the 

 soil. Another striking discovery was the determination of 

 lactic acid as the normal vegetable acid of sisal. The 

 percentage of acid increases from the base to the tip of the 

 leaf. It might be worth while extracting it provided the 

 corroding action on machinery vrere overcome by using gun 

 metal in the place of iron. 



CHICLB GU.M IN RUBBER L.-ITEX. 



Amongst the miscellaneous chemical researches were 

 the studies which led to the conclusion that sulphate of 

 ammonia is the best nitrogenous manure for the taro crop, 

 and that which showed that the new rubber product from 

 Eiqjhorhia laurifolia can be coagulated only by using heat 

 or alcohol. An interesting fact is, that the dry matter of the 

 latex of this plant contains 14 to 17 per cent, of rubber and 

 about 60 per cent, of resin, which appears to be nearly if not. 

 quite identical with ohicle gum. 



