DRAINAGE AND IRRIGATION 25 



thing put into the bottom of the trench to form a passage-way 

 for the water and then the trench filled up again. 1. The 

 most common closed drain is the one in which tile is placed 

 in the bottom of the trench to carry the water. 2. A box with 

 open ends is frequently used to carry off the water. The 

 box may be square or triangular. 3. Flat stones may be 

 arranged so as to make a covered way for the water. 4. Two 

 poles may be laid along the sides of the bottom close together 

 and a third one put on the top of these to make an open pas- 

 sage. The poles will soon sink into the mud and stop up the 

 passage-way. 5. The bottom of the trench may be filled with 

 brush and these covered with straw or pieces of sod to pre- 

 vent the loose dirt from washing in. The trench is then 

 filled with dirt. All forms of under-drains described, except 

 tile, are likely to be temporary and poor, and hardly pay for 

 the labor of making them. 



There are two great objections to open drains. 1. Open 

 drains use up a good deal of land on which no crop is grown. 

 If an open ditch is ten feet wide it does not need to be very 

 long to use up an acre of land. Then, too, besides the open 

 part there are the two banks on which we cannot raise any- 

 thing. If such a ditch were tiled with large tiles it could be 

 filled up and crops grown on it. 2. Open ditches are always 

 getting filled up with grass, weeds, brush and mud. If hogs 

 can get to an open ditch thej soon work down the banks and' 

 fill it up. If open ditches are not kept cleaned out they are 

 soon worse than useless. 



When Drainage is Necessary. — Almost all of our farm 

 soils are helped by drainage. Only sandy soils and those 

 which have a gravelly or sandy subsoil do not need drain- 

 age. Of course the soil in the far west in what is called the 



