276 



THE AGKIGULTUKAL NEWS 



September 8, 1917. 



THE HORSE BEAN AS A GREEN 

 DRESSING FOR CACAO. 



Interesting notes on some experiments with the Horse 

 Bean (Canavalia ensiformis) ab. to its value for growth under 

 cacao trees in Grenada have been furnished by the Superin- 

 tendent of Agriculture in that island. This bean has been 

 used as a green dressing in lime and cacao orchards in 

 several West Indian islands for many years, and also 

 as a green dressing for s^rable land, as may be seen by 

 reference to the Annual Reports of Experiment Stations; but 

 its use for this purpose appears to have been neglected in 

 Grenada. 



That the attention of Grenada cacao planters has now 

 been aroused to the possibilities of this bean as a suitable 

 green mulch for their plantations is evidenced by the fact 

 that between .5,000 and 6,000 BE), of cleaned seed has been 

 distributed by the Agricultural Department during the 

 eighteen months ended .June .30, 1917. 



The chief point in the experiments was to discover 

 whether the Canavalia, possessing as it does the valuable 

 properties of other leguminous plants, would thrive well 

 enough under the shade of cicao to justify its cultivation for 

 creendres-sing purposes, so as to maintain or restore the 

 fertility of land under cacao. 



These experiments as far as they have gone, serve 

 to support the idea that the Canavalia will furnish q, desir- 

 able leguminous green dressing for cacao land. 



The first of these experiments was conducted by the 

 proprietor of Tuilleries estate. An acre of land under cacao, 

 about .500 feet above sea-level, was sown with the beans in 

 May 1916. The beans were planted two in each hole at 

 a distance of 2 feet apart. The cacao trees on the plot are 

 about twenty years old, carefully pruned, with foliage fairly 

 thick. They stand from 10 to 14 feet apart. 



In October the bean plants were about 2 feet high, 

 flowering and bushing well, though, as was natural, there was 

 a noticeable degree of attenuation in the growth, caused by 

 the shade of the trees. Fourteen months after sowing the 

 bean plants continue to thrive, and have produced a fair yield 

 of seed. 



The second experiment has been carried out by the 

 managing attorney on Boulogne estate, on poor land. The 

 cacao trees on the 3 acres experimented with are about fifteen 

 years old, growing at an average distance of 10 feet apart. 

 They are well pruned, but only moderately vigorous; hence 

 the shade was less than in the first case. Three acres were 

 sown broadcast with Canavalia beans, about half of the plot 

 being sown in December 1916, and half in January this year. 

 In May this year the plants on the earlier-sown portion 

 were about 1 8 inches high, and thick enough almost to hide 

 the soil from view, and were beginning to flower. On the 

 later-sown portion the plants were about 12 inches high. 

 In .June the plants in both portions were of fine growth, 

 covering the soil completely. 



On July 5 a trial cutting of the plants on the first-sown 

 section was made. This indicated a yield of 4i tons of fre.sh 

 cut material per acre. It was also estimated that the weight 

 of stumps and roots left in the ground would be about :,--ton 

 per acre — a total weight therefore of 5J tons per acre of 

 vegetable matter. 



It has yet to be determined whether the beans will 

 ratoon well under the shade conditions of a cacao plantation. 

 A continuation of these experiments will yield valuable 

 and reliable information as to the suitability of the Canavalia 

 to be used as a green dressing, under conditions of very con- 

 siderable shade. 



AN EXPERIMENT IN STORING SEED- 

 CORN IN GRENADA. 



An instructive and succe.ssful experiment in .storing 

 locally grown seed-corn has been conducted in Grenada by 

 the Superintendent of Agriculture, Mr. J. C. iloore, who has 

 furnished this Office with a detailed report, of which the 

 following is a resume. 



It must be temembered that corn kept for sowing 

 purposes, and that stored for food purposes cannot be 

 subjected to the same treatment. In the latter case the corn 

 is dried at a considerable temperature, the process destroying 

 to a certain extent its germinating power. In the former case 

 the object is to preserve this power, at the same time 

 eliminating as much moisture from the seed as possible 

 without destroying its vitality. 



In October 1916, the Superintendent of Agriculture in 

 Grenada advised that an attempt be made to store locally 

 grown corn to provide a supply of seed for general distribu- 

 tion in May and June 1917. Accordingly, in November, 60 

 barrels of corn selected from peasants' crops were stored in 

 a room at the Botanic Station. This room is constructed 

 mainly of wood, with a shingled roof, having a capacity of 

 3,120 cubic feet, and is well ventilated, the windows and 

 ventilator openings being, however, .screened with 1-inch mesh 

 wire-netting. 



The ears of corn, tied together in pairs by one or two 

 of the segments of the ha.sk, left on for the [)urpo.se, were 

 hung across racks made of 6-inch boards placed edgeways in 

 tiers spaced so as to insure free circulation of air throughout 

 them, and to facilitate inspection; the total length of the 

 racks being 426 feet. This afforded ample space, as it was 

 calculated that 5 teet of rack could approximately hold the 

 ears contained in a barrel, when the ears were hung three 

 or four deep across them. 



Windows and ventilators were kept fully open, except 

 at night and during actual rainfall. A few weevils were 

 noticed on the corn immediately after hanging, having prob- 

 ably obtained a lodgment there before the purchase of the 

 corn. The only fumigation effected at this stage was by 

 the fumes of a smouldering wood-fire for about six hours at 

 a time on three occasions, at intervals of two weeks. 



Shelling began on January 5, 1917. After being 

 shelled, the corn was 'sunned' for two days, sifted in order to 

 remove dust and chaff, fumigated with hydrogen cyanide for 

 .sixteen hours, and immediately stored in a bin. Owing to 

 limited facilities this process took some time, being only 

 completed on February 1. 



The storage bin, 71 feet high and 4 feet square, was 

 constructed of boards closely fitted, one half of the top being 

 fitted with a movable cover. The inside of the bin was lined 

 with roofing paptr tacked on with overlapping edges, and 

 the outside tarred to secure tight joints. The bin was pro- 

 vided with a flue suitably perforated, running from the bottom 

 of one side half-way across the floor, then ri.sing vertically 

 through the centre of the bin to 18 inches from the top. The 

 lower portion of the flue was made large enough to hold 

 a gas generator, and fitted with a tight door. The cyanide 

 fumes were thus enabled to penetrate thoroughly the stored 

 corn. 



As the corn was put into the bin, muslin bags, each 

 containing 3 oz. of crude flake naphthalene were distributed 

 at regular intervals throughout the mass. This did not seem 

 to be efficacious in warding off insect attacks. 



Fumigations of cyanide were applied on February 13 

 and 23, and on March 8. Two further fumigations of 

 carbon bisulphide were applied on March 16 and on May 1-5. 

 When emptied on May 23, a large number of weevils 



