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crease the storage capacity for excessive precipitations. This will 
not only save the surface from being washed and gullied, but it will 
also increase the store of moisture held by the soil, which is of very 
great value in the time of drought. 
It is important also for this, as for other reasons, that the soil be 
covered with vegetation as much as possible throughout the year, 
as the roots and organic matter serve to bind the grains of the soil 
together, in some parts of Holland the drifting sands of the coast, 
which shift the position with every storm, often cover up valuable 
farming lands. Vast areas of these sands have been reclaimed and 
made productive by being covered with vegetation, while the roots 
and remains of organic matter hold the soil grains in place and 
prevent them from drifting and covering up more valuable lands. 
Any crop which requires very clean culture, as tor example, cotton, 
is exhausting to the land for the reason that constant exposure of 
the surface to the sun and storms uses up the organic matter, 
makes the soil less porous, and the soil particles themselves are 
more easily washed away % so that clean cultivation is in its 
effects very favourable to excessive erosion. 
Another very effective method, when properly carried out, to 
prevent the washing of lands is to underdrain the soil with tile or 
other drains. These drains carry off quite rapidly an excess of 
moisture, so. that much more of the rainfall is absorbed by the soil 
and carried off through the drains and less washes over the surface 
of the land. Not only this, but a vvell-underdrained field is usually 
dryer and more porous, and has a greater capacity for absorbing 
excessive rainfall and thus preventing surface washing. A field 
thoroughly underdrained with tile drains will carry off the water of 
any ordinary rainfall without any surface erosion. This method is 
very effective, but is likewise very expensive, and cannot be used 
economically in extensive farming solely for this purpose of pro- 
tecting the land from washing. 
While the land may thus be made more porous and more absor- 
bent of water through the increase of the amount of organic matter 
or of humus through the use of lime and other fertilizing material, 
through the deepening of the soil by gradually increasing the depth 
of cultivation by so cropping it that it shall be covered with vegeta- 
tion as much of the year as possible, and by underdraining the 
land-still, these methods may not be sufficient to so change the 
chemical and physical texture of the soil as to enable it to absorb 
the rain as it falls and to prevent an excess of water washing and 
eroding the surface where the contour of the land is such as to pro- 
mote erosion from the surface flow of the excess of water. 
It will be necessary in this case to provide for a more uniform 
distribution of the flow over the surface, and to prevent any accu- 
mulation of water which would have the effect of a torrential stream. 
This is secured in a great measure by laying off the rows according 
to the contour of the surface, so that each row will have a very 
slight incline of not more than from i to 7 inches in 100 feet, and 
