Vol. XVI. Xo. .395. 



THE AGRICULTURAL NEWS 



189 



SOIL AERATION AND THE GROWTH OF 



SAL SEEDLINGS. 



A series of papers is being-r published in the 

 Indian Forest Records on the < neology of Sal {Shorea 

 ■rohusta). Part III deals with soil areation and water 

 culture. In summarizing the results of the investi- 

 gation. Mr. R. S. Hole, F/J.H., F.L S., says:— 



The present experiments have confirmed the results 

 previously obtained regardint; the very injurious eifect of bad 

 aeration on the growth of Sal seedling.s in the local forest soil. 



When water is long held in contact ■With this soil, which 

 is the case under conditions of bad aeration, it becomes heavily 

 charged with carbon dioxide and impoverished as regards its 

 supply of oxygLMi. 



The bad growth of Sal seedlings in this soil is correlated 

 with an accumulation of carbon dioxide in the soil .solution 

 and a low oxygen content, and this possibly explains the evil 

 effects of bad aeration. Further work, however, is required 

 to prove this and also to decide the relative importance of 

 carbon dioxide and oxygen, respectively. 



Liming this soil, immediately before sowing, has an injuri- 

 ous effect on Sal seedlings, and during tlie rains, soil wlucli has 

 been thus limed appears to contain more carbon dioxide and 

 less oxygen than the unlreated soil. It seems pn.ssible that 

 this may be clue to accelerated bacterial activity. This 

 point, however, requires further investigation. 



As carbon dio.xide is rapidly dissipated and a deficiency 

 of oxygen made good under the ordinary conditions of water- 

 cultures, it is not easy to prove the effect of varying quanti- 

 ties of these gases on plants grown in such cultures. For 

 the same reason, artificial aeration of such cultures may not 

 show any beneficial result. 



As Sal seedlings caa be successfully grown in water- 

 cultures, the injurious etTect of bad aeration is not due to 

 water as such. This probably explains the fact that Sal cm 

 grow in practically saturated soil on the banks of rivers or 

 even of stagnant lakes, in which the water is kept well aerated 

 by exposure to the air or the presence of green aquatic plants. 



Suggestion of Anti-Mosquito Measures in 



Antigua. — The prevention of malarial and filarial diseases 

 in Antigua and the Leeward Islands generally has not received 

 much attention hitherto. In order to induce the co n|icration 

 of employers of labour throughnut the island in a cnmpiv- 

 hensive scheme of mosquito destruction, the author of a recent 

 paper [Dr. W. M. McDonald] proposes the establishment of 

 an experimental area in which various anti-mosquito mea.sures 

 may be tried, a record being kept of their relative cost and 

 efficiency, and of the return of malaria in this area. The 

 utilization of natural enemies is a measure which has 

 to be applied with a due regard to the many methods 

 by which mosquitoes may escape attack. . It was observed 

 in this connexi'in that while small fish occurred in great 

 numbers in the open water of certain ponds, mosquito 

 larvae were also very numerous among the grass and vegeta- 

 tion round their edges. The latter must therefore be kept 

 clear if the fish are to be of use • 'iling is likely lu prove 

 the most practical method of dealing with the majority of 

 breeding places in the island, while draining is also to be 

 tried. (From the Review of Applied Entomology, Series H, 

 Medical and Veterinary, February 1917.) 



EXPERIMENT STATION IN THE 

 ARGENTINE. 



The new members of the staff of the Experiment Station 

 in the Tucuman Province in the Argentine have already taken 

 up their duties, and the Experiment Station which is now 

 well organized, both for research and technical consulting 

 work, is rapidly approaching the maximum of usefulness and 

 value for the Province. 



The principal function of the Station is that of investiga- 

 ting the most important agricultural and industrial problems; 

 to discover the best varieties of plants already cultivated, and 

 introduce new crops; to try . to incre ise the production per 

 acre, and improve as well as cheapen the methods of culti- 

 vation; to help by means ui the investigation of prob- 

 lems and difficulties, the industries of the Province; to 

 discover new industries by means of scientific experiment- 

 ation, and encourage them; and to study the insect and 

 fungus pests of the Province with a view to exterminating 

 'ir controlling them. 



The reports giving an account of the investigations 

 carried out by the different departments will be published, as 

 is usual, in the Eevista Iniustri<d y Agricohi dr. Tucuman, 

 the official organ of the Station, and in order that the 

 Province may be able to take as much advantage as po.ssible 

 of the results of the experiments and investigations, the 

 practical conclusions of the work in each case will be p'lblished 

 in the form of circulars, which will be distributed amongst all 

 interested. 



The second important function of the Station is that of 

 giving advice and help to agriculturists and others in their 

 struggle against the difficulties and problems which they 

 encounter in their work. Naturally, the Station cannot 

 promise to solve all the problems presented for study, but, 

 in a large percentage of the difHculties which are met with 

 in the agricultural and industrial life of the Province, the 

 advice and technical help of the. Station will undoubtedly 

 be of much service. 



It is hoped, therefcjre, that the agriculturists and 

 manufacturers of the Province will co-operate with the 

 Experiment Station in studying carefully their problems, and 

 that they will follow the recommendations and advice given 

 as a result of the investigations. 



Finally, in order to give more publicity to the reports 

 of the Station, it has been resolved to distribute the Ee»ista 

 gratuitously all over the Province. It is hoped by this means 

 to increase the usefulness both of the magazine and of the 

 Station itself in the Province of Tucuman. 



Forests of Porto Rico. —A recent Bulletin com- 

 prises a report of a survey of forest problems in Porto Rico, 

 conducted by the Forest Service in co-operation with the 

 Government of Porto Rico. It also revises and brings up to 

 date two previous Bulletins of the Forest Service dealing 

 with the forests and forest conditions of Porto Itico. A 

 general account is given of the phy.sical and economic features 

 of Porto llico, together with a discussion of the condition 

 and distribution of forests, forest formations, forest influences, 

 commercial aspects, forest industries, products and problems, 

 and suggestions relative to an insular forest policy. 



.Appended to the P.uUetin is a descriptive account of 

 Trees of Porto Rico, by W. D. Bru.sh, L. S Murphy, and 

 0. D. Mell. Each species is described with reference to its 

 nomenclature, distinguishing characteristics, wood structure, 

 and economic uses. A bibliography of consulted literature is 

 also appended. (Ej-periment Station Record, Vol. .Y.XXVI, 

 No. .3.) 



