239 



the hill side, or l)roug]it l)y the floods which frequently occur. It 

 is therefore of an alluvial character, of good depth and of a fine 

 loamy texture, the very best medium one would think for a trial 

 of this nature ; actually however, it was not at all suitable. 



To begin with, it had been for years under a rank, semi- 

 aquatic vegetation of wild grasses and of Pandanus (Screw- 

 pine), with a few stunted Eubber trees. The large sago-palms 

 growing near-by, mark the land for what it really is namely 

 an undrained, almost uiidrainable swamp : its structure, a 

 peaty bottom overlaid with the rich silt brought by floods. 

 Such is the land with tlie exception of the small plot of 

 1 V of an acre referred to above, a gentle slope at the foot hill, 

 well above flood level. Here is no drift or alluvial soil but the 

 ordinary coarse yellow sandy clay, characteristic of Singapore hill- 

 sides. 'This small plot had been for some years under cultivation 

 and sundry annual crops had been raised off' it in 1917 by Pro- 

 fessor Baker (see Gardens Bulletin July Ith 1918). Xoav, it is 

 off this small plot of rather poor and thin material, tliat the crops 

 of Lima beans were grown hy the writer, the results of which were 

 given in the Bulletin of 4th July 1919, and on it are still to be seen 

 beds of Lima beans of healthy growth, with abundant crops on 

 them. One bed, in particular, sown on 31st July 1918, shows at 

 date of writing, quite a fair crop of young pods. What, then, is 

 the explanation of the unsatisfactory return of the ensemble of 

 the crop? How is it that the promising results previously oljtain- 

 ed, as shown in Bulletin Xo. 4 of 1919, now fail? 



In the writer's opinion, this failure is due to the host of 

 diseases l)rought about by fungi and insect pests which are 

 bound, in the natural course of tilings, sooner or later to attack 

 and destroy plants grown under adverse conditions in an uncon- 

 genial soil. And here, for the sake of clearness, one may be per- 

 mitted a slight digression. In some countries, Burmah for in- 

 stance, we hear of the Lima bean being grown on alluvial 

 deposits formed along the river banks, by the silt of periodical 

 inundations, a condition resembling somewhat that under which 

 the Economic Gardens are placed. But there is this difference be- 

 tween the case of periodical seasonal floods and the case of occa- 

 sional floods which last only a few hours over undrained land. In 

 the one case, the parasitic fauna and flora is killed by the prolonged 

 sojourn of the waters on the land, moreover the steady withdrawal 

 of the river water to a much lower level as the floods subside, 

 allows of perfect drainage of the alluvial deposit left on the land. 

 Thus a perfectly new soil is formed, perfect in nutritive elements 

 for plant life, perfect in physical texture, and above all, a soil 

 purged of fungoid and. insect pests — a clean soil which, with a 

 minimum of tillage, will bear such wonderful crops of tobacco and 

 indigo as one sees, for instance, on the ])anks of the Mekong. 



In the other case, new soil is brought on the land, carrying 

 with it seeds of parasitic vegetation and spores of new fungi whioh 

 find a congenial home in the rank vegetation, a vegetation which 

 thrives all the more for a short immersion, and as the land drains 



