Vol. XVIII. No. 446. 



THE AGRICULTURAL NEWS. 



165 



wjuld be iateresting if experiments on these lines were made 

 in these islands, and the results reported, the two plants in 

 question being neither of them poisonous. It would bi 

 advisable, however, to hn cautious in experiments with 

 cassava leaves, on account of the hydrocyanic contents of 

 the plant. 



LIME CULTIVATION IN DOMINICA. 



c;heex DUEssixi; and di'.st muli.'hes. 

 As an addendum to the series of articles which 

 have been reproduced in recent issues of this Journal 

 from the Report on the Agricultural Department, 

 Dominica, lately issued, the following remarks are 

 taken from another portion of the report, which give 

 further information on green dressings best suited for 

 use in connexion with lime trees: — 



Gn-en t/n'ssings. During recent years over thirty 

 species of green dressings have been grown with a view to 

 finding which are besl suited as nurse plants in young lime 

 cultivations. There are many kinds of green drf-ssings, and 

 all pos ss a value under certain circumstances, but tho ideal 

 nurse plant and soil enricher for young limes should be a 

 biennial, with a bush like habit, which would give a good 

 cover, grow to a height of 4 or 5 feet, w th a life of eighteen 

 months or two years, or even longer. T^j possess seedi of 

 a fair size, with good germinating pnver, which could be 

 easily col'ected, is nnoil er desirable quality. 



At present this Heal plant has not been found. The 

 most useful grown in the E.x;periment Station have been the 

 Tephrosias, particularly T. nndida, which has afforded a 

 good cover for a peri d of two years. The several species 

 of Indigofera have also cinsiderable possibilities in tliis 

 direction. In both cases mentioned above, the see Is are 

 small, and difficult to collect and clean. The Tephrosias are 

 als»> very uncertain as regards germination. The pigeon pea 

 (Ca/aiuia indiciis) has its uses in this direction, but it is not 

 sufficiently dense-headed to prevent I he grass from growing 

 below, though it weak> ns the ia'.ter consiJerably. 



For covering the ground, several species of Mucuna 

 (Stizolobium) and other peas and beans have been found 

 snitable, but the tendency of this class of plant to climb 

 and cover the young lime trees is a drawback in Dominica. 

 Besides, lime plants rec[uire more than aground cover. They 

 need shelter, and this is aff rded by the Tephro.sias and 

 Indigoferas, which attain a height of from 5 to 6 feet or more. 

 The combination of groun'l cover and shelter is a great help 

 to the limes at a critical period of their existence, that is, 

 when between the age of two and five years. 



For a ground cover, the horse bean (Ca/uwdin 

 eifii/oriiiis) has proved very useful- It has been fnund to do 

 best when sown with the rains in May. It then grows 

 vigorous'y through the wet season, giving a fairly good cover 

 until November If sown at later periods of the year, 

 it commences to flower and fruit early, which causes the 

 foliage to remain thin and unsatisfactory. It can be grown 

 at any season for the production of seeds. As a cover plant, 

 the best results are obtained by sowing with the rains. 

 The same remarks apply in the case of Tephrosias. The 

 best results, both of germination and growth, are obtained 

 by spring sowings. 



It is generally held that the growing of green dressings 

 amongst young limes on estates is too costly. To prepare 

 the surface of the soil for the seeds does cost considerably 

 more than an ordinary weeding, but if a nood gr jwth of 

 Tephrosia follows, the planter is relieved of weeding for a 



period of eighteen months, during which time the soil is 

 protected and enriched, and the plants nursed and kept in 

 a healthy and growing condition. 



Lime trees at the Experiment Station, with Tephrosia 

 as a nurse plant, arc at four years from planting, from 12 to 

 14 feet in height, and are bearing heavily. Other trees of 

 the same age, grown without green dressings, are only half 

 the size, and not likely to fruit for some time. 



It is clear thit great advantages follow the use of 

 leguminous plants with a bush-like habit in young lime 

 cultivations. 



Trials with new tireen dressings during the year were 

 few. Seeds of the sunn hemp { Crolahiria j iincca) were received 

 from St. Kitts. This plant grows and seeds well, but it is 

 too short-lived to possess any considerable value in orchard 

 cultivation. Towards the end of the year seeds of 

 Crotalari'i usamar^iensis and Centroseiiia Plunieii were 

 received from Java, and are now under trial. 



Since the foregoing was written, Mr. Jones, the 

 Curator of the Botanic Gardens, Dominica,has furnished 

 a note on the possible advantages of employing dust 

 mulches in the cultivation of lime trees. This, as 

 bearing on the whole question, is now reproduced below: 



T/h' dusf mulch. Anothe- form of mulching, which 

 appears to be unknown to lime p'anters, is the dust mulch. 

 By this is meant the working or stirring of 2 

 or 3 inches of surface soil in arable cultivation. By 

 this means the capillarity of the soil is broken, and the 

 evaporation of water considerably retarded, much to the 

 benefit of the plants growing upon it. 



In orchard cultivations the spreading over the surface 

 of a thin layer of soil, such as is obtained in making or 

 scraping drains, has the same effect, and this saving of water 

 enables the trees to p.iss through considerable periols of 

 drought with less sutTering than in cases in which no 

 mitigating work is undertaken. 



Some surprise may ba expressed as to any reference of 

 the need of a dust mulch in a rainy country like Dominica, 

 but, as lately experienced, very severe droughts may ojcur 

 along the leeward coast, which is the main producing 

 area of the island. Plants which are accustomed to an ample 

 rainfall sutler severely during prolonged periods of dry weather, 

 and any method which tends to mitigate such conditions, and 

 which can be put into effect easily is worthy of considera 

 tion, 



Experience recently gained in the Experiment Station 

 shows that planters are well advised to carry oit such 

 instalmonts of draining as are necessary during the early 

 and dry part of the yeir, and bef 're the ground becomes very 

 hard. The loose soil thrown out and spread over the land 

 acts as a dust mulcli, and proves effective during droughts. 

 Lime plants, both young and establish^'d, treated in this wayi 

 show none of the signs of suffering exhibited by trees grow- 

 ing on land without this treatment. 



It will be seen that properly laid out fields receive each 

 year a top dressing as part of the annual routine work of 

 cleaning the drains. This connexion between a good system 

 of drainage and dust mulching is important in dry situations. 

 Undrained areas lack this treatment, and the trees suffer 

 considerably. In the latter case it is advised that the 

 system of drainage by the instalment plan, as recommended in 

 the note on drainage, should be carried out. 



This matter of dust mulching while of interest on 

 the leeward coast of Dominica is of far greater importance, 

 and capable of a wider application in other islands in th ; 

 West Indies in which limes are grown under much drier, 

 conditions of climate. 



