Ill 
SOIL AMELIORATION. 
By J. F. C. Hagens. 
. 11. 
Correction of unfavorable conditions due to the natural location. 
DRAINAGE. 
But few cultivated plants will grow in swampy or constantly 
wet soils, particularly if the water is stagnant. This is not caused 
by any direct injurious effect of the water upon the plant but by 
the continued exclusion of the atmosphere. The presence of air 
in the soil is very essential to most plants. Water is a poor con- 
ductor of heat and wet soils are therefore usually cold. The 
wetter the climate and the greater the waterholding power of the 
soil the more necessary becomes the proper drainage of such soils. 
The removal of the excess water promotes proper aeration of 
the soil, since air will fill the space formerly occupied by the 
water, and besides favorably affect the temperature of the soil. 
The chemical and biological processes, so necessary to plant life, 
take place under more favorable conditions and consequently more 
thoroughly. 
The manner of drainage depends of course on the local condi- 
tions causing the excess moisture in the soil, which are manifold 
and require careful study before a definite plan of action is de- 
cided upon. Frequently we find unfavorable subsoil conditions 
which prevent the usual downward movement of the soilwater 
and in such case the removal of the excess water is best accom- 
plished by a proper system of drain ditches, following the natural 
slope of the land. Where the land, to be drained, is level with, 
or below the level, of a nearby river, lake or the ocean the water 
must often be pumped out of the main ditches to accomplish the 
desired results. Low lands, situated near the ocean, often become 
salt wastes after they have been under cultivation for a consider- 
able period. This is due to change brought about in the condi- 
tion of the soil through the cultivation. The salty subsoil water, 
by capillary attraction, rises to the surface and is there evapor- 
ated, leaving its solids in the form of a salty crust or shining 
crystals. Unless occasional heavy rains dissolve them and carry 
them oft' such deposits will gradually become heavier and heavier. 
This surface washing is only possible where the land has a natural 
slope ; on level low lands drain ditches must be built to accom- 
plish it. 
Soils are drained either by under-drains or surface-drains. As 
a rule drainage by a system of open ditches is the most practicable 
and economical, particularly where land is comparatively cheap 
and where large bodies of water must be removed. On the other 
hand where land is valuable and where only moderate quantities 
