FARM IRRIGATION 253 



may be laid directly upon the bottoms ; but usually 

 it is safer to provide some foundation for the cement, 

 preferably flat stones. The advantages of a cement- 

 lined ditch over an ordinary one are that it pre- 

 vents seepage and washing and carries the water to 

 its destination quickly, so that little is lost by 

 evaporation. Such ditch linings are not safe 

 except in mild climates as they are likely to be 

 heaved by hard frosts. 



Whatever the method of distributing the water 

 it should be carried along the highest part of the 

 field to be irrigated. From this head ditch the 

 water is applied to the land by gravity. 



METHODS OF APPLYING WATER 



The methods of securing, storing and distrib- 

 uting water are largely matters of engineering, 

 although they have a direct and vital relation to 

 successful agriculture on many American farms. 

 The point is now reached when the water must be 

 applied to the soil; here agriculture begins. The 

 problem of securing sufficient water to water the 

 farm economically is often very difficult, calling for 

 much ingenuity and engineering skill. But the 

 problem of applying this water to the land, so that 

 both soil ana crops will receive the most benefit, is 

 much more complex. The engineer can help the 

 farmer bring water to the farm successfully and 

 economically, but the problem of how best to use 

 this water on the land each farmer must solve in his 

 own way. 



The use of water, like the use of fertilisers and 

 manures, is not capable of being formulated into 

 definite rules applicable for all farms, or even for 

 any considerable number of farms ; chiefly because 



