10 
Beport of the Director op the 
Cultivation. 
The effect of cultivation may be looked for in two directions. 1. 
The direct influence upon the plant through changes of habit induced 
by root pruning. 2. By its effect upon the root pasturage of the 
plant, induced by the physical changes produced thereby. This latter 
view is one to which I shall here give prominence. 
The following propositions are justified by our accumulative data: 
The water of the soil may be considered from two points of view ; 
one, water of percolation, the other, water of capillarity; the water 
of percolation meaning that which passes downward by gravity, the 
water of capillarity meaning the water which is held and distributed 
by capillary action. During the growing season, evaporation is in 
excess of the rainfall with reference to bare soil or with reference to 
transpiration from plant growth. Consequently the direction of move- 
ment of the soil water in this climate is upward rather than downward. 
The upward movement of the water being in excess of the downward 
movement during the growing season, the tendency of plant food is 
therefore toward the surface, and the water of the drainage does not 
necessarily represent the amount or character of the soil fertility 
available for crops. The water of the rainfall rarely penetrates to the 
drains, as it is not sufficient to saturate the soil above the drains. 
The drainage water is hence water of displacement, and its composi- 
tion consequently becomes but a measure of the soluble salts which 
have escaped the upward movement. 
Evaporation is a surface phenomenon. Any process which obstructs 
the outlet of capillary attraction to the surface, retards evaporation- 
This obstruction may be anything which breaks capillary connection, 
whether it be straw or manure in layers beneath the surface, or 
whether it be recently turned sod, or whether it be a mulch of fine 
particles upon the surface. 
Cultivation, as the term is ordinarily understood, or inter cultural 
tillage as it is preferably to be called, pulverizes the upper soil and, 
effecting a soil mulch, protects the capillary outlets from surface 
exposure, and thus conserves the water to the soil. 
The extent of the conservation of water through the prevention of 
evaporation by cultivation, as measured by the lysimeters in 1885, 
from May to September inclusive, with the rainfall of 14 . 42 inches, 
as between bare soil and cultivated soil, was about 1 . 4 inches, and as 
between cultivated land and sod land about 2 . 25 inches. In other 
words, we may arrive at a just appreciation of the effect of the process 
of cultivation upon modifying the physical character of the soil by the 
