and Magazine of the Ceylon Agricultural Society. 38d 



little to teach us in regard to methods to be 

 employed in rearing forest trees in the tropics. 

 Bacteria which are largely responsible for the 

 continuous supply of plant food to the roots 

 cannot exist in a dry baked soil and the roots 

 themselves cannot live under these conditions. 



MALAYA SOILS AND DEAINAGE. 



The soils in Malaya are physically excel- 

 lent in their structure, though not chemi- 

 cally very rich, and possess the requisite 

 amount of plant food for para rubber cul- 

 tivation. Many places require little or no 

 artificial aids to get rid of excess of water — 

 the structure allowing water to percolate freely 

 while not being too loose to partially retain it. 

 Drainage is a factor, the importance of which 

 the planter has learnt by experience. If the 

 soil is water-logged and consequently not 

 sufficiently aerated rubber roots will not grow 

 vigorously. He has still to learn the advantages 

 of protecting his soil from sun and rain or 

 rather the disadvantages of exposing it to these 

 inimical influences. His drains are made chiefly 

 to decrease the loss of surface soil after rain 

 but if he will cover his land with a beneficial 

 weed the only drains that will be necessary will 

 be those on flat land which prevent the land 

 becoming waterlogged. Nearly all the expenses 

 of draining are thus saved and a sum of from 

 $1/- to $4/- per acre in order to permanently 

 establish a protective plant which will 

 obviate the necessity for drains on sloping 

 land and at the same time 



ENCOURAGE THE ROOT GROWTH 



of his rubber trees, can readily be afforded, 

 especially as it raeansa cessation of all expense 

 in regard to weeding or attending to drains. 



Millions of dollars have been spent on keeping 

 the land on which rubber is growing exposed 

 and probably three quarters of the labour force 

 have been used in carrying this out. Hundreds 

 of thousands of tons of top soil, which can never 

 be replaced and the value of which as plant food 

 is immense have been washed off clean weeded 

 estates. Is this expenditure of money and labour 

 and sacrifice of top soil necessary in order to get 

 the most rapid and vigorous growth of rubber 

 trees ? This is a problem which any planter can 

 solve himself. Let him the next time he is 

 opening a clearing 



SOW OR PLANT A SELECTED GREEN MANURE 



Crotalaria, Mimosa (sensitive plant) Vigna, 

 Desmodium, &c, or even Passiflora foetida 

 (passion flower) directly the burning is finished 

 and see that it is established so that the ground- 

 is never exposed to the sun and the rich top 

 soil which is left behind when jungle is burnt 

 is not immediately washed off. Let him plant 

 his rubber in this and compare its height and 

 girth and general vigour with the growth of 

 rubber trees of equal age in his clean weeded 

 clearings and I have no doubt that he will be 

 convinced that the labour and money spent on 

 clean weeding is not a sound commercial invest- 

 ment. If he establishes his selected plant at 

 once, there is no fear of lalang that bugbear of 

 the rubber, getting admission. 



During the past three years I have been 

 making observations as to rubber which for 

 various reasons has been allowed to remain in 

 weeds or has had other plants growing with it 

 which tend to protect the soil from sun and 



rain. In cases where the weed is lalang the 

 benefit of the protection of the soil is to a great 

 extent counteracted by the damage done by this, 

 the worst of all the weeds of Malaya. 



LALANG 



forms a close mat of roots which absorb a great 

 deal of rain and dew, the leaves of the plant 

 do not protect the soil nearly as well as almost 

 any other plant, being all arranged vertically 

 and thus giving as little shade as possible. I 

 have found the surface temperature in lalang to 

 be some 8 to 10 degrees higher than in other 

 weeds, sensitive, plant, passion flower, &c, on 

 similar soil. Even where lalang is the weed, the 

 hindrance to rapid growth of the rubber is not 

 so marked as believers in clean weeding would 

 expect. No serious planter would allow if he 

 could avoid it the invasion of lalang ; but looked 

 at purely from a commercial aspect, the position 

 in regard to lalang on many estates is that the 

 rubber trees have been checked in their growth 

 compared with weeded trees about £ ; that is 

 to say a live year old tree is only equal to a four 

 year old tree which has been tended, but the 

 cost of the weeding during the three years of 

 the tended tree has been from $30 to $60 per 

 acre, and it is a question whether the hastening 

 by a year of the tree's growth is worth the cost 

 paid for it. With other weeds the advantage of 

 covering the soil usually balances the dis- 

 advantage caused by the weeds taking moisture 

 and plant food from the soil at the expenses, 

 the rubber roots. To take exact instances, 



AN ESTATE IN PERAK 



planted in rubber was owing to want of 

 funds abandoned for five years and allowed 

 to grow up in belukar. When cleared up only 

 8 per cent, of the trees were missing and the 

 remainder showed excellent growth and are to- 

 day at eleven years old giving 4 lb, of dry rubber 

 per tree per year though they have been tapped 

 some years. There are many thousands of acres 

 of rubber in the Malay States and the Colony 

 under Tapioca the cropping of which takes more 

 plant food out of the soil than almost any known 

 cultivation aud even with this tax upon the soil 

 the rubber trees benefiting from the shading of 

 their roots are growing not very much less 

 vigorously than their neighbours with no com- 

 petitors but with their root areas exposed to 

 sun and rain. 



To put it briefly the policy of scrape, clean, 

 expose, let in sun and rain should be 



EXCHANGED FOR THE POLICY OF PROTECT, COVER, 

 RETAIN, 



prevent the baking of the sun and the washing of 

 the rain. Without any detriment to the rubber 

 this method of cultivation reduces more than 

 considerably the cost of bringing a rubber estate 

 into bearing. 



This question was dealt with in my annual 

 report for 1907 published in this Bulletin for 

 September of that year and has been further dis- 

 cussed at length in my report for this year about 

 to be published. It is of so much practical 

 importance that no excuse is needed for its 

 reiteration in order to urge the planter to give 

 the whole matter serious consideration and — 

 what is still better— to carefully try the effect of 

 green manure or cover plants as against the 

 more usual method of bare soil. — Straits Agri- 

 cultural Bulletin, for Sept. 



