Vol. XVI. No. 385. 



THE AGRICULTURAL NEWS. 



19^ 



would involve little additional labour to pit and rot 

 them. These stools contain a considerable amount 

 of saccharine matter, and would possibly form an 

 e.xcellent medium for bacteria. 



INTERESTING 



HORTICULTURAL 

 IN HAWAII. 



WORK 



ABSORPTION AND LOSS OF NITROGEN 



IN CONNEXION WITH SUGAR 



ESTATES. 



The International R'A'iew of the Science and Practice or 

 A'jiiculttire (JnnelQlC)) contains the following .summary of 

 work in .Java to determine to what extent nitrogenous 

 manures are made use of by sugar-cane. 



The question of the absorption and loss of nitrogen 

 in the soil after the application of nitrogenous manure is nf 

 prime importance in the cultivation of the sugarcane in Java, 

 where every year at least 50,000 tons of sulphate of 

 ammonia are used, costing about £G.3.5,000 for a cultivated 

 area of 246,954 acres. 



In a series of specimens from different districts under 

 sugar-cane, the loss of nitrogen occurring on mi.xing a solution 

 of sulphate of ammonia with the soil was determined. 



For the purpose of analysis 50 gms. of dry earth are 

 first mixed with 50c. c of water and the whole afterwards 

 with -dOcc. of a one-fifth normal solution of sulphate of 

 ammonia. The mixture is regularly sh-aken up for two days, 

 then filtered, and, by distillation, the amount (if ammonia 

 in 20c.c. of the filtrate is ascertained. Multiplying by 14 the 

 number of cubic centimetres of declnormal ammonia obtained 

 by distillation (it should be below the limit 20), the coeffi- 

 cient of absorptiu.T of nitrogen is ascertained. 



Analyses made, show that for the majority of soils with 

 a coefficient of absorption exceeding 140, no loss need be 

 feared. Some lands with a coefficient below 80 might 

 sustain a loss under particularly unfavourable circumstances, 

 .such as torrential rains or floods. 



Soils of coarse texture have a low coefficient of ab.sorp- 

 tion and a fairly considerable loss of nitrogen. On api)lying 

 a heavy dressing of manure, the lo.ss of nitrogen increa.ses. 



On determining the coefficient oi absorption by a given 

 soil, it may be ascertained to what extent manuring with 

 suljihate of ammonia may be effective without entailing 

 a considerable loss nitrogen 



Contrary to the nitrogen in sulphate of ammonia, that of 

 nitrates is not absorbed by the soil. It having been necessary, 

 owing to the present war, to replace sulphate of ammonia by 

 nitrates in sugarcane plantations, it was thought desirable 

 10 study the various soils utilized for sugar-cane growing 

 from the stand-point of absorption of the nitrogen from 

 nitrates. 



It was found that none of the soils analysed hnd any 

 high coefficiient of absorption On subjecting the same soils 

 with nitrate added, to leaching for three days, a considerable 

 quantity of nitrogen from the nitrate, it was found, had 

 been leached out. 



The conclusion drawn from the invesstigations is that 

 the use of nitrate of soda in tropical countries during or 

 before the rainy season is of no advantage. [Tiiese findings 

 have reference to heavy rains capable of washing the nitrate 

 out of the soil.] The employment of nitrate of potash on 

 permeable, highly irrigated soils, is also not to be recom- 

 mende<l. 



In Kurope, the action of nitrates is more rapid and effec- 

 tive than that of sulphate of ammonia. In the tropics, where 

 nitrification is so rapid, this ilitfereiice in the behaviour of 

 .sulphate of ammonia is unimportant. 



The Experiment Station Record, Vol. XXXV, 

 No. 6, gives an account of recent work at the Hawaii 

 Agricultural Experiment Station, in the following 

 words: — 



The station is co-operating in experiments in Florida and 

 in California with the view of extending the culture of litchi 

 (Litchi chiiiends). Some successful experiments in transport- 

 ing these shortlived seeds under refrigeration from Honolulu 

 to San Francisco, and thence by ordinary express and by 

 mail in moist sphagnum moss to Washington, D.C, and to 

 various localities in California are noted. All of this seed 

 germinated well, thus indicating that litchi seeds may be 

 transported where refrigeration for fruit is available. 



In the work with mangoes some preliminary studies have 

 been made on the flowers of certain varieties, and on methods 

 of pollination. Several mango seedlings less than nine 

 months old, which had been grafted by inarching, were- 

 found to be producing flower clusters above the point of 

 union, and in most cases the scion also was flowering. The 

 mango tree ordinarily does not flower until it is from five to 

 six years old. No cause is ascribed for these phenomena, 

 except the grafting. An instance of bud mutation is reported^ 

 in which a single branch of one of the trees bearing green 

 fruit produced a pink fruit rather smaller in si/.e than the 

 regular type, but otherwise resembling the variety. Bark 

 grafting the mango, which has previously been successfully 

 applied by the Porto Eico Experiment Station, has pri>ved 

 to be well adapted under Hawaiian conditions to the work of 

 top grafting established trees. The process is here described. 



In the work with avocados, the Macdonald, the parent 

 tree of many of the round, hard shelled winter .seedlings, has 

 attracted some attention by its remarkable keeping qualities. 

 The fruits were kept in the horticultural laboratory for six- 

 teen days without any refrigeration, being in a perfect state 

 of preservation at the end of this time. 



In the work of propagating the avocado, scion budding 

 has given satisfactory results. The scions are inserted in 

 a T-shaped incision similar to that made for .shield budding, 

 only much larger. After being tied in place the budded 

 scion is waxed with a firm grafting wax which will not run 

 when heated by the sun. This method is considered to be 

 advantageous as a means of propagating from old bearing 

 trees which frequently do not produce good bud wood unless 

 severely cut back. It may also be used to work branches of 

 considerable size. Observations of apparently multiple- 

 stemmed seedling avocados showed that such seedlings have 

 a single central stem, the other stems arising from buds on, 

 this stem beneath the surface of the ground, and in many 

 cases within the .<eed. 



The work of breeding papayas was resumed along lines 

 previousfy noted. A number of cro.s.ses and close pollinations 

 have been made to secure information on questions arising in 

 earlier work. 



In the citrus orchard many varieties are now in bearing 

 and making a satisfactory growth. I'mctically all of these vari- 

 eties have been introduced as a bud wood and work upon 

 home-grown stocks. 



In view of the claim by some manufacturers that a blend 

 of the oil of kukuri {Alturites moluccana), and of the Chir:i 

 wood o\\ (A. fordii) \i preferable to either one, some work 

 was undertaken by V. S. Holt in hybridizing these species 

 with the idea that the new forms might combine the desired 

 characters in a way superior to either of the parents. 

 A number of fruits from these cross pollinations have beea. 

 secured. 



