174 Lime Requirements of New Zealand Soils 



Average per- 



Since the coarser fractions are those that tend naturally to make 

 soils open and friable, while the fine silt and especially the clay are 

 affected by the action of lime, one must conclude that-the response of 

 these soils to liming is in no way connected with the amehoration of 

 their texture, at any rate so far as the surface soil is concerned. 



7. Character of sub-soil. The soils of which the mechanical analyses 

 are tabulated above are samples drawn 6 in. deep, this being the depth 

 of soil usually stirred by the plough in routine work in these districts. 

 Up to the present time, I have not collected enough samples of the 

 sub-soil to make possible a useful comparison, though on my collecting 

 tours I made extensive notes of the character of the sub-soil and of 

 the miderl3ang formation. In general the soils of the Terrace Lands 

 overKe deep beds of a somewhat sandy clay, exceedingly dense in 

 texture, and almost completely impervious. These beds range from 

 3 ft. to 8 ft. in depth, and lie upon the old gravels mentioned on a 

 previous page. The soils of the River Flats are from 8 in. to 2 ft. in 

 depth and he upon very open loose gravels of recent deposition. There 

 is thus a fundamental difference in the nature of these two soil areas: 

 the soils of the River Flats are naturally exceedingly well drained and 

 ventilated ; those of the Terrace Lands tend to remain water-logged in 

 the wet weather, for they have no under-drainage, and their mechanical 

 constitution favouring the retention of water, they he wet till the 

 moisture is drawn off by the natural slope of the country. It is not 

 surprising therefore to learn from the practical farmer in this area that 

 draining is an essential prehminary to liming. 



Turning to the Canterbury Plains, we find here a great diversity of 

 sub-soils, from the open gravel beds typically seen in the Burnham 

 district to the sandy clay sub-soil met with on this College Farm. But 

 in comparing the retentivity for moisture of the soils of Southland and 

 Canterbury a new factor comes into operation, namely the annual 

 rainfall and other chmatic conditions. 



8. Meteorology. The principal items in the meteorological statistics 

 of Southland and Canterbury are shown in the accompanying Table XII, 

 which is abstracted from the Official Records. More complete informa- 



