Vol. XIV. No. 352. 



THE AGRICULTURAL NEWS. 



347 



with success. It maybe pointed out, however, that when on 



the ground, the weevil a . diffi il 



on account of its prol ration. Rotation oi 



crops should certainly be practised, md all old 



should be pulled up and burnt, oi | I in the i I pens, in 



order that the larvae may havi unit] of completing 



their life history. 



Tliis pesl is und 01 to be reckoned with 



seriously and it mat) prove very diffi mtrol. Cowpeas 

 mature in i comparatively short time, and thus escape serious 

 damage. 



(To be contim 



LOCUSTS IN DEMERARA. 



In the Agricultural M 19,191 in article 



ired "ii the subject oi in I rinidad, a severe 



outbreak of which occurred in the San Fernando district List 

 MayandJune. Papers that have recently come to hand 

 indicate that a plague has now broken out in Demerara. 

 According t>i the Daily Argosy of October 2, Mr. G. E. 

 Bodkin, Government Economic Biologist, has paid a visit 

 to the Corentyne * loast, Berbice, with the object of investiga 

 ting and controlling the outbreak. It appears from the 

 report that great difficulty was experienced in carrying out 

 the necessary measuri ng to the indifference and laziness 



and, to some extent, the suspicion of the coolie inhabitants. 

 When after some difficulty a gang had been procured it 

 is ible to begin to collect the locusts in kerosene tins, 

 and to burn them in deep pits with kerosene oil. 



Towards the end of the report are reproduced the 

 following notes extracted from the Bulletin oj the Depart 

 of Agriculture, Trinidad and Tahago, on the subject of 

 locusts Mights in that colony. — 



'From time to time large flights of this locust come over 

 to Trinidad from the mainland of Venezula. Its particular 

 food-plants appear to be banana leaves, coco-nut palm leaves, 

 Indian corn, cassava, peas and sugar-cane. Cacao was not 

 touched. 



'Control measures consist in digging up the eggs, and also 

 in the destruction of the young hoppers by driving them into 

 trenches and there burning them with kerosene oil. The 

 as ■ ot atsenicals Is also advocated.' 



Mr. Bodkin goes on to say that the Trinidad locusts 

 present infinitely greater danger to cultivators than the 

 species occurring at the present time in Berbice. The name 

 of the species is not given, but it is apparently < j u i t e distinct 

 from Schistocerca paranensis, the form which occurs in 

 Trinidad. The latter is said to be smaller, and it moves in 

 vast swarms according to the habits of a true migratory 

 locust. The species of locust thai damaged cultivations in 

 1 886 was, as far as can be ascertained from the incomplete 

 records in the British Guiana museums, Acridium vicarium. 

 The sudden appearance of Schistocerca paranensis in 1 lemerara 

 is well within the bounds of pos ibility. 



In Zanzibar the principal crop is cloves. The average 

 yield per annum from a plantation of 3,000 trees of about 

 sixty years old, owned and managed by Europeans, is 8 lb. 

 per tree: ninety-eight trei planted to the acre: the 



price varies according to the size of the crop. The price 

 of recent years has varied from Rs. 8-8-0 to 1 I ">-0 per 

 frasla of 301b. The Governmi i duty oi 22 per cent, 



on all cloves exported. Coi inks next in importance to 



clove. It is estimated thai there are about 45,000 acres 

 under coco-nuts in the two islands. 



FIXATION OF NITROGEN IN INDIAN 



SOILS. 



The 'punt 1m of nitrogen -ays Dr. biutchinsoti 

 (Bacteriologist to the [mperial Di pa at ol Agricul- 

 ture in India), which leaves that in the form of 

 agricultural products is tnfinitel) gi atei tl in the 



■ nut returned to the soil eithei 



manure or leguminous plants. It is very impo 

 therefore to encourage the activities of Azotobacter and 

 Clostridium organisms which are capable ol ni 

 fixation from the atmosphere while living a free life in 

 the soil. The following conclusion- were arrived at 

 by Mr. J. H. Walton, B.A., B.Sc, Supernumerary 

 Bacteriologist, in regard to azotobacter and nitrogen 

 fixation in Indian soils, and the paper to which 

 refer is published in the Memoirs of the Department, 

 (Bacteriological Series. Vol. 1, No. 4). 



The nitrogen-fixing power of Azotobacter in cultures 



inoculated with I'nsa soil compares \er\ favourably with that 

 observed by other investigators. 



There is a well marked seasonal variation in the 

 nitrogen fixation in cultures inoculated with soil. 



Pure cultures of Azotobacter isolated from different 

 soils vary in nitrogen-living powerand in morphological and 



cultural characters. These i 'phological and cultural - h 



ters are constant in any particular variety. 



Black pigment occurred only in impure cultures. 



Nitrogen fixation in soil is increased by cultivation and 

 the addition of suitable carbohydrate material. We may 

 conclude that proper soil management shculd include the 

 provision of conditions favourable to the physiological 

 activity of Azotobacter, namely aeration, the presence of 

 lime, and the presence of available carbohydrate food. The 

 increased nitrogen fixation observed as resulting from the 

 addition of humus, and the experimental demonstrati 

 Koch that cellulose may be acted on by micro-organisms in 

 the soil so as to make it available as carbohydrate food for 

 Azotobacter, emphasize the importance of such agricultural 

 operations as tend to maintain the supply of organic 

 in the soil. 



The study of the physiological effect of rations from 

 single plant sources up in cows subjected to the strain of 

 reproduction, carried on by the Departments of Agricultural 

 Chemistry and Animal Husbandry lor the past seven years, 

 has narrowed itself down to a detailed study of the corn and 

 wheat plants on reproduction. In all of the work 

 a chemically balanced ration from the wheat plant and its 

 products has never produced normal calves, while a 

 from the corn plant has always produced vigorous offspring. 



In view of theories held bv various investigators it was 

 thought possible that the injurious effects of the 

 restricted to the wheat plant might be due to the prepond- 

 erance in the mineral matter of acids over alkalies or to the 

 large amount of magnesium compared with calcium. Ho 

 it' has been impossible to correct tic ol 



by the addition of various alkaline salts. It has also been 

 found that disturbing the balance of mineral matter in the 

 corn ration by the addition bi various salts, or even rendering 

 the ration acid by the use of mineral acid-, did not lead to 



injurious results. (Wisconsin Bulletin, No. 250.) 



