52 ELEMENTS OF AGfllCULTUKE. 
more impenetrable to the roots of plants. A medium con¬ 
sistency agrees best with vegetation. This may be ol> 
tained by hauling upon the l&nd a quantity of humus ; bu. 
as this method would be too costly, particular substances 
are made use of (that we shall describe hereafter), called 
ameliorators (mineral manures). 
73. If too close a texture is injurious to vegetation, too 
loose a one is not less so, and very sandy land is of little 
or no value. In a blowing sand, plants can not take the 
fixity that they require, and are forced to fall. 
74. All soils are not of equal depth; they vary from 
half an inch to many feet. 
75. Deep soils possess over others important advantages. 
They retain moisture better in seasons of drought, without 
becoming too wet in rainy weather. When equally rich, 
they furnish plants with a greater mass of food than other 
soils. Longnrooted plants, such as lucerne, and tap-rooted 
plants,* such as beets, parsnips, carrots, etc., thrive best 
in soils of great depth. 
QUESTIONS. 
1. Are the physical properties of the soil of any consequence to the 
cultivator? 
2. What ought first to be looked to by a farmer wishing to lease or pur¬ 
chase a farm ? 
3. Why should we seek to know the texture and depth of a soil ? 
4. What is meant by the consistence of a soil ? 
5. What are the defects of too much closeness ? 
What is the best consistence ? 
7. Will humus bring it about ? 
8. What are the inconveniences of sandy soils ? 
9. Are all soils of the same depth ? 
10. What advantages do deep soils possess over others ? 
11. Which are the plants that thrive best in a deep soil ? 
* Tap-roots are those that descend perpendicularly, to a certain depth, ia 
the soil. 
