496 The Supplement to the 



WEED SUPPRESSORS. 



April 29th. 



Dkar Sir, — We have had quite a number of 

 climbern and twiners recommended for suppres- 

 sing weed : — 



(1) Passiflora foetida, (2) Mikanea Scandens, 

 (S) Ipomaea ymosa, (4) Venonia Zeylanica, (5) 

 Commclina Nudiflora. 



None of these, however, exert any specially 

 beneficial action on the soil, while serving as 

 weed suppressors. 



I am inclined to add to the above list Mucuna 

 utilu (commonly known as the velvet bean) and 

 would recommend that it, or even our local M. 

 pruriens, be tried for the same purpose. It is a 

 rank grower, even on sandy soils, and an excel- 

 lent restorative crop, while it also smothers 

 weed c and is itself a useful fodder. I may men- 

 tion chat the velvet bean thrives well in the 

 lowcountry. 



To prevent misapprehension it is as well to 

 state that the reputation of Commelina Nudiflora 

 as a weed suppressor is an entirely spurious 

 one. The "wee modest" plant of our paddy 

 fields (the Sinhalese " girapala" with its brilli- 

 ant blue flowers, has probably got confused 

 with some robust climber.— Yours truly, 



C. D. 



P. S.— The following extract from the West 

 Indian Agricultural News of March 6th, which I 

 have seen since writing the above, will speak 

 for itself :— 



Very favourable reports on the results of culti- 

 vating the velvet bean (Mucuna Utilis) for green 

 dressing purposes, and as a forage crop for 

 cattle, come from South Africa, more particu- 

 larly from Rhodesia. In the South African 

 Colonies the crop is stated to have been grown 

 with great success for some years past ; it has 

 given good results even on dry lands, and does 

 not appear to suffer much from drought. 

 A light sandy soil is best suited for the velvet 

 bean, and on this it grows so thickly and 

 forms such a large mass of vegetation, that 

 all weeds are choked out. Being a legumipous 

 crop, this plant is naturally of high value 

 for improving the soil. In experiments 

 carried out at Barbados in 1900, the velvet bean 

 came second out of thirty varieties of legu- 

 minous plants tested for the weight of produce 

 yielded. In from two to three months a crop 

 of vines was produced, the weight of which 

 amounted to 12,343 lb. per acre. The velvet 

 bean is largely grown as a cover crop in orange 

 orchards in Florida. 



FIGHTING THE DROUGHT. 



April 26th. 



Dear Sir, — The recent drought in the Chilaw- 

 Puttalam District, and its effect upon coconuts 

 and other cultivations, has set a good many 

 minds athinking as to the best course to be 

 adopted under similar conditions in the future. 

 The great trouble in that district (and parti- 

 cularly on the boi ders of the Deduruoya) is the 

 low level to which the water tablo sinks. 



Prof. Whiting, one of the foremost authorities 

 on questions connected with the soil, refers to 

 a case that came within his own experience. 



Tropical Agriculturist 



where the water table, during a severe drought, 

 fell to 40 feet below the surface ; and yet he 

 saw tobacco growing and thriving in spite of the 

 fact that no rain had fallen since the tobacco 

 was planted. Of course, proper cultivation had 

 been going on all the time, with the result that 

 when the loose top layer of soil was scraped 

 away, a moist layer was found beneath it. The 

 Professor is inclined to attribute this condition 

 — so much to be desired in drought-stricken 

 areas— in a great measure to the special meteo- 

 rological conditions that prevailed in the re- 

 gion with its dry air, hot climate and strong 

 winds which rapidly carry away moisture from 

 the surface. 



It would, therefore, appear advisable in 

 similarly situated areas, subject to severe 

 droughts, to take action immediately rain 

 falls, by working the top layer of soil 

 with a view to getting it into a oose and dry 

 condition, so that the moisture below it might 

 be conserved. 



It will thus bo seen that a humid atmos- 

 phere under such conditions is a disadvantage, 

 rather than an advantage, inasmuch as it would 

 favour evaporation of moisture from the soil, 

 whereas a dry atmosphere would rapidly carry 

 away the moisture from the surface layer, and 

 reduce further evaporation from below to a 

 minimum. 



Strange as it may sound, though crops suffer 

 if they do not get rain, they are actually better 

 off if they get no rain during the growing 

 season, but tho means of being supplied 

 with moisture when necessary. The most per- 

 fect condition for cultivation, according to a 

 competent authority, is an arid climate with 

 water available for purposes of irrigation. If 

 this is so, we could wish for nothing better 

 that the North-Central Province, with its irri- 

 gation works restored ! One would like to have 

 the opinion of an expert like Mr. Strange on a 

 question of this nature. 



With rain at tolerably frequent intervals there 

 is a natural inclination for the cultivator to 

 believe that his crops are getting all the 

 moisture they need, and there is also the ten- 

 dency to neglect surface tillage for the pro- 

 duction of a " dry mulch." Such a mulch 

 would, of course, be destroyed at every fall of 

 rain, but must be constantly renewed if the 

 water in the soil is to be saved for the use of 

 the plant. 



The moral of the tale for the cultivator, whose 

 land lies within a drought-stricken area, is to put 

 all available hands to cultivate it just after rain, 

 so as to prevent the moisture from being carried 

 away, as it surely will afterwards. Cultivation 

 should consist of surface tillage which should 

 be kept up during the dry weather that fol- 

 lows, so as to preserve a loose top layer of 

 soil or, as the Americans call it a " soil blan- 

 ket." Occasional deep ploughing or digging to 

 loosen the soil below and allow rain water to 

 sink in, and frequent shallow cultivation should 

 be the rule, but judgment, prompt action 

 and perseverance are required in anticipating 

 what is coming, beginning operations at the 

 proper time and keeping it up. — ¥ ours truly, 

 DELTA. 



