15 Oct., 1919.] 



Pear Growing in Victoria. 



587 



It may be said by some that scientific pruning and manuring are the 

 chief essentials for regular bearing, but, without discrediting the im- 

 portance of these in any way, it must be recognized that the ideal soil 

 conditions enumerated, and produced mainly through good drainage, are 

 really the governing factors of maximum effects from other orchard 

 operations. 



"A proper condition of soil-tilth is necessary to enable the oxygen 

 from atmosphere and rain water to penetrate freely through the soil, 

 and this is not possible if a water-logged condition exists, as such soil is 

 sealed against the air. In a well-drained soil, however, this surplus 

 water passes away by filtration and gives place to air in addition to the 

 moisture films surrounding the soil particles. As air is so important in 

 promoting growth, it will be seen how necessary it is to rid the soil of 

 any obstruction to its free passage and consequent aeration of the soil. 



It is impossible to maintain a good soil-tilth unless the land is 

 properly drained, as " wet " land becomes hard, lumpy, and dried out 

 in summer time, when a good state of soil-tilth is so essential to moisture 



Plate 19. 



1. — Soil grains and air space surrounded by moisture films (magnified). 



2. — A. Airspace. B. Water film. C Soil grains with water film i magnified). 



conservation and the promotion of free root action. This adverse condi- 

 tion of the soil will persist in undrained land, despite the efforts of the 

 grower by cultivation, &c., to alter it. (See plate 18a.) 



Increased and More Regular Moisture Supply. 



An erroneous and rather common idea is that drawing off surplus 

 water from the soil is the only benefit of drainage. It does much more 

 than that. In fact, it actually provides more moisture in the summer 

 time, when the trees require it most, for during the warm season un- 

 drained land becomes dried out and unable, through its harsh and lumpy 

 condition, to hold moisture like the soil in drained land with its better 

 physical condition. This explains the saying that, " The better the 

 drainage the surer the water supply," a statement opposed to commop 

 idea of drainage results. Thus we can claim for well drained land, pro- 

 vided the drainage is accompanied by surface cultivation, a regular 

 moisture supply instead of an oversupply or lack, as the case may be, in 

 undrained land. 



