THE SOIL 



ii 



served. In this way so to put it a good manager can make 

 up for. a deficient rainfall and can do much to ensure good 

 growth and healthy conditions for the trees on the estate which 

 is under his charge. 



There are, perhaps, four classes into which soil may be 

 roughly divided. First, there are the light, sandy or gravelly 

 soils; second, there are loam soils; third, clay soils; and 

 fourth, humus soils, that is, soils largely composed of decaying 

 vegetable matter. 



Light, sandy or gravelly soils have sometimes a good stiff 

 sub-soil, and thus trees are enabled to establish themselves and 

 to resist the effects of drought. If, however, the light surface- 

 soil is of considerable depth it will be exceedingly difficult to 

 establish young trees, and the trees, even if established, will 

 always surfer severely in times of drought. In such cases 

 manuring with chemicals is of little service. The best plan 

 to follow is to stiffen the soil with an abundance of green 

 manure as frequently as possible till it assumes a good texture. 

 The term " loam " is one very often misapplied. Loam 

 consists of a good mixture of sand and clay. It is a sort of 

 intermediate soil, being neither sand nor clay, but a thorough 

 intermixture of both. It is better than either for the purposes 

 of most cultivations, including rubber, being neither too porous 

 nor too tenacious of moisture. 



By the term " humus soil " is meant a dark soil, largely 

 composed of decayed matter of vegetable origin. Such soil 

 is exceedingly fertile and full of bacterial activity. 



While most soils are composed of particles varying largely 

 in shape and size, in clayey soil very minute particles pre- 

 dominate. In droughts, as already stated, soils which are 

 largely composed of sand or gravel are the most readily affected. 

 In such coarse soils the sum total surface of the grains of which 

 the soil is composed, and the wideness of the interspaces, pro- 

 vides them with but very limited powers of drawing up sub-soil 

 water to the roots of the trees. It may be generally stated 

 that the greater the proportion of very small particles in soils, 

 the larger is the amount of water that can be retained and 

 drawn up. Clayey soils, therefore, naturally retain much 

 more water than a coarser soil is able to hold on to. This, 

 however, is not always an advantage, because the water retained 



