row carry off its own proportion of the excess of rainfall so gently 
that there shall be no erosion, thus acting as a miniature drain. 
Practically, however, it is often impossible to keep these rows from 
breaking through, and when the bed is once broken and the water 
overflows into the next row the accumulation of water is sufficient 
to break down he'd after bed until the rows from all the field are 
discharging into this narrow channel. 
To overcome this difficulty sidehill ditches may be used in which 
larger and more substantial ditches are provided, following very 
nearly the contour of the field, so that there shall be a fall of from 
[ to 6 inches in 100 feet. The distance apart of the ditches will 
depend upon the slope of the field; with a very steep slope they 
should be close together, often not over 6 to io feet apart; with a 
gentle slope they should be at intervals of 15 or 20 feet, or even 
further apart, depending upon the texture of the soil and the con- 
tour of the surface. 
These sidehill ditches are very easily constructed, being made 
almost entirely with the plough. A bank is formed by running a 
number of furrows, throwing the dirt toward the middle. The last 
furrow on the upper side is cleaned out with a spade to form the 
bottom of the ditch. If the plough is well handled it takes very 
little work with the spade to make a very substantial ditch. It is 
well to get the bank forming the lower side of the ditch sodded 
with grass to help hold it and to lessen the danger of its giving 
way during a heavy rainfall. When the slope is thus protected 
with a number of ditches at the proper distance apart, the rows can 
be given a rather steeper fall so that they shall run out into the 
drains at frequent intervals and not have to carry the water so far. 
These ditches have to be constructed .with care and have to be 
strengthened where they cross any depression or sudden curve by 
building up an embankment. Unless these ditches are thoroughly 
constructed they are worse than useless, for if they break they con- 
centrate a volume of water upon one point in the field which would 
otherwise have been distributed over the surface, and this often 
forms a torrent which does great damage. 
It is essential that these ditches and rows be run according to 
the contour of the surface of the land, and that there shall be* no 
low places where the water would accumulate and gather force. 
They should always be run with a level, of which there are several 
tofms on the market suitable for this work. 
A more efficient, but at the same time much more expensive, 
method of preventing the washing of lands where there is consider- 
able slope is to terrace the field so that there shall be level steps 
upon which the water can rest for a while and be absorbed. In 
terracing, the lines are run with a spirit level following the contour 
of the surface so as to give a perfect level line. A furrow is run 
along this line, and a similar furrow is run along a lower contour, 
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