As far as oxygen is coueerued this element is of impoxtaiice uot 

 only in the atmosphei'e, but also in the soil. Here it plays an 

 impoi'taufc part in the formation and transformation of most nuti-itive 

 compounds, and it is essijntial in the ground, because the roots of 

 plants breathe in the same Avay as the stems and branches breathe. 

 Oxygen is also required by many bacteria, which are important for 

 transforming certain foodstuffs into absorbable compounds, for 

 instance, tx'ansforiuing ammonia into nitric acid, in which fonu the 

 plants take most of their suppl}' of nitrogen, and also for transform- 

 ing decaying matter into absorbable substances. 



In a Jiard and compact soil the bacteria lef erred to do not thrive, 

 and tlieir well-being is only ensured by cultivation. 



If the gix)und is not properly ventilated suitable solutions cannot 

 be formed either for want of water or for want of air, and it is thus 

 obvious that a well aerated and permeable soil is of the greatest 

 importance to the plants. 



On uncultivated land the watei-, which is the main factor in all 

 plant life, cannot penetrate jn-operly. After heavy showers it just 

 runs off, and I believe that starvation of rubber trees is frequently 

 due to an insufficient supply of water. 



Cultivation helps to retain the water, and between old trees it 

 also helps to retain fallen leaves, which are often washed away if 

 the surface is too smooth. 



Cultivation is mostly done by changkolliug and amongst old 

 ti-ees this cannot very well be done othei'Avise, but young cleax'iugs 

 can almost always be treated cheaper and better by the use of 

 agricultui-al implements, ploughs and haiTowSj. 



In the coui-se of time sevei-al different kinds of harrows have 

 been tried on plantations, and at a certain pei'iod disc harrows 

 were much in favour. On the estate with which I am connected 

 we also tried some, but we did not find them satisfactory. In hai*d 

 soil the discs could not work, and where they worked they only 

 loosened a couple of inches of the soil, resulting in very bad wash. 



About two and a half years ago we commenced ploughing, and 

 on one of our sections 2,200 aci-es out of 2,800 have been treated. 



The fii-st ploughing was done by a small one-handled American 

 plough, '■' Cuzou," which did very good work, but since then a 

 bigger tyjje of a two-handled Danish plough, " Fi^ugde," ha.s 

 been introduced and is now used exclusively. It is quite an oixlinary 

 plough, but so strongly made, that it does not bieak when 

 encountering the usual obstacles in the ground. 



I know that some planters have tried ploughing and given 

 it up on account of the difficulty of teaching the bullocks to di-ag the 

 plough, but 1 may say that we have never expeiienced any trouble 



