19 



have already stated in another of my publications, the primary 

 means for bringing this about is by means of subsoil drainage. 

 It is not my intention here to lay down again in detail the principles 

 on which such drainage should be carried out. The matter has been 

 very fully dealt with from a scientific point of view in Dr. Watt's 

 " Pests and Blights of the Tea Plant," (pp. 66 94), and with the general 

 principle he lays down there I am in perfect agreement. It may be 

 well, however, to insist that drains are not intended to be channels into 

 which the water runs from the surface. Every drop which does so 

 is so much evidence of the unsuitability of the drains, and all should 

 run through the soil and not over it to get into them. In land with 

 a stiff subsoil such as I am now considering the drains should be at 

 least 3 feet deep (often far more than this if they are in sand over- 

 lying clay for then they must go down to the clay), as narrow as 

 possible, banked upon each side if on flat land, or on the upper side if 

 running across a slope, and never with a fall of more than one in three 

 hundred. Such drains as these tend to form a deep soil. There is a 

 simple channel for the water to run away, and they absolutely prevent 

 if properly made, the rise of the ground water above their own level. 



Subsoil drains form the fundamental method of deepening a soil, 

 and of making it penetrable to plant roots to a greater depth, There 

 are other means which taken together have a similar effect, but none 

 of these nor all together can replace a rational drainage system. 



VERY DEEP CULTIVATION. 



Very deep cultivation is one of these methods. The whole 

 question of very deep cultivation and its value has been so much 

 discussed in recent years that it may be well to consider here its 

 meaning and purpose and so ascertain where and where not it is 

 profitable to cairy out extremely deep hoeing. 



Deep cultivation where applied in tea culture appears to have 

 three objects in view (i) the production of a layer of loose soil on 

 the surface which will retain the moisture during the very dry 

 season from November to March, and which will do this better the 

 thicker the loose layer is ; (2) the prevention of the formation of 

 trunk roots branching in any direction from the bush above the 

 depth to which the cultivation penetrates ; (3) the prevention of the 

 formation of a hard pan. 



