282 ALFALFA FARMING IN AMERICA. 
too high and strong and the water will be ponded too 
long in a check. There ought to be no more than 
about 12” difference in the levels of the upper and 
lower sides of these contours. The earth for mak- 
ing the levee should all be taken from below it. This 
will avoid making the inequality of the land more 
than it need be. The levees ought to be strong, high, 
at least 6” higher than ever needed, and better if 12”, 
and of easy slope so that the mower can run over 
each one and thus save what alfalfa may grow 
thereon and at the same time prevent weeds growing. 
There should be large volume of water, so that 
the checks may be rapidly filled. A small stream 
will not serve at all since it will put water on the 
lower parts of the checks long before it will reach 
the upper sides, and thus one part of the field will 
get too much water while the other part will get not 
enough. If only a small stream of water is available 
the land should be prepared for flooding rather than 
for ponding, or preferably be irrigated by the fur- 
row method, if the stream is very small. 
Irrigation by the Fiurrow Method.—This is 
adapted to certain types of soil that soak well. On 
coarse, sandy or gravelly soils it will not serve, 
since the water sinks and will not penetrate side- 
ways very far. Nor will it serve well in hard clays, 
since there it penetrates too slowly. It is in good, 
loamy soils that the furrow method works best. 
There furrows 6’ apart, or even at wider distances, 
will moisten all the land between them. The furrows 
ought to flow nearly in a direct line down the slope, 
