AGRICULTURAL BULLETIN 



OF THE 



STRAITS 



AND 



FEDERATED MALAY STATES. 



No. 11.] NOVEMBER, 1909. [Vol. IX 



PEAT SOILS. (Continued.) 



In Warming's Oecology of plants he deals in chapter 84 with the 

 formations in acid soils, but his observations are only made on those 

 of cold climates. Formations like those of our so-called peat- 

 formations occurring in the tropics seem to be rare, and no records 

 have been made of them. 



The action of these soils on plants is, however, practically the 

 same as in the temperate swamps, the main difference being that 

 in the tropics the soil is composed of branches and trunks of large 

 trees, while in temperate regions it is composed of smaller plants, 

 bog-mosses, grasses and heaths. In the temperate regions a 

 specially adapted flora has been produced to meet the demands of 

 the peculiar soil, but in our limited areas, which seem to be of very 

 modern age, there cannot be said to be a xerophytic flora developed 

 from this soil formation as yet. 



The factors which go to make these soils xerophytic, although 

 one would naturally expect them to be hygrophytic, are given as 

 follows : — 



One of the factors is an increase in Transpiration, that is to say 

 the plants exhale a greater quantity of water than they can afford, 

 and even marsh plants specially adapted to grow in such localities 

 may be forced to reduce their transpiration. Wei soil is cold, and 

 therefore physiologically dry. We have na record of the temperature of 

 these peat soils here, but this factor may affect the growth of rubber 

 in such spots. Respiration is obstructed ( the soil being poor in 

 oxygen ), and the roots functional activity depressed. This is a 

 serious factor, and that this is of the greatest importance to plants 

 is shown by the occurrence of aerating roots to trees in the wet, 

 swampy peat woods of the peninsula. Many of those who have had 

 to walk through such spots must have noticed the knees or projecting 

 roots of certain trees rising a foot or more above ground in the from 

 of cones. They are most abundant in the mangrove mud where the 



