DRAINAGE 61 



tages of closed or under drainage, where it may be used, are 

 obvious. It does not interfere with the cultivation of crops 

 or other operations conducted on the land. 



Benefits of Drainage. Preparatory to the installation 

 of the farm drainage system, must come the consideration of 

 the benefits to be derived and an estimate to determine the 

 advisability of the expenditure required, from the stand- 

 point of an investment. Certain drainage systems may be 

 justified as a protection to the health of the people of the 

 neighborhood. This value cannot be computed in dollars 

 and cents. Yet most farm drainage must be considered from 

 the business standpoint. In this connection full considera- 

 tion should be given to all of the benefits which may be 

 derived from the improvement of the land by drainage. In 

 general, it is to be expected that drainage will either reclaim 

 the land for farming purposes or make it more productive. 

 There are various ways in which land is made more produc- 

 tive by drainage. 



Soil is Made Firm. When the level of the hydrostatic 

 water is lowered, the soil above becomes more firm. Thus the 

 wet marshy field in which a horse would mire may be made 

 so firm by drainage as to permit a team and load to pass over 

 it safely. 



Soil is Made of Finer Texture. It has been proven con- 

 clusively that drainage causes the soil to become divided 

 into smaller particles, thus enabling it to hold a larger amount 

 of capillary water. The agents which bring about a disin- 

 tegration of the soil particles in underdrained soil are the 

 percolation, or passing of the water down through it, and the 

 action of air and frost. 



The Growing Season Is Lengthened. Drainage lessens 

 the amount of water that evaporates from the surface and 

 the amount in the soil to be raised in temperature, permitting 



