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soil is tarned into a slushy bog, on which the operations of plough- 
ing and digging are carried on under great difficulties and with little 
if any good results. During the hot, dry summer months, on the 
other hand, these quagmires dry up and turn as hard as bricks. 
What few roots the plants have been able to preserve from rotting 
during the winter months in turn dry up and perish in the baked 
soil in which the plant has been thus placed. 
Draining may be said to sweeten the soil by checking the 
formation of the sour products of fermentation and rotting of the 
organic matter it contains; it also removes the excess of saline 
matters in the soil, and prevents alkaline salts from rising from 
below. It equalises the temperature of the soil, and prevents any 
possible chill to the plant. It restores to health plants suffering 
from attacks from fungus diseases. It brings warmth to the roots 
in the winter time and keeps them cool during the summer months. 
It deepens the layer of soil the roots of plants feed in. It favours 
the absorption and the circulation of air and moisture, and thus helps 
to pulverise the soil and unlock its fertilismg elements, which are 
made available for the rootlets. Drainage of cold, damp ground 
favouring a higher temperature in the soil, hastens the growth 
of plants, and thus often brings on maturity of the fruit several 
days earlier. 
Drainage is effected by several methods, viz., open drains or 
underground drains. Open drains again comprise arterial and 
surface drains. 
Arterial Drainage embraces a comprehensive scheme for 
draining a large patch of country. This work is generally under- 
taken by the State, as its benefits extend not only to one or two 
particular settlers, but to the whole district at the same time. Such 
schemes have been carried out by the Government in the vicinity of 
the Harvey agricultural area, at Hamel, near Busselton, and other 
localities. The size of these drains depends upon the gradient; the 
less the gradient, the greater the capacity of the drains. In order to 
keep it clear of silt, a gradient of at least one foot per mile is 
necessary. Streams of smaller size require a gradient of three feet 
to four feet per mile, whereas minor ditches require at least eight 
feet per mile. In order to guard against the erosion of the sides and 
the banks being undermined by the water, the soil is eut open at 
an angle which varies according to its nature. In sandy soil an angle 
of 45deg. is required; in loamy soils, an angle of 60deg. or 70deg.; 
whilst clay may be cut almost perpendicularly, as it has much 
tenacity. 
A velocity of three inches per second will remove fine clay; of 
six inches per second, fine sand; eight feet, sand; twelve inches, fine 
gravel; and 24 feet will carry off pebbles. Where the ground is 
