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For row crops there is no 

 uniform practice. The sys- 

 tems at Continental are 

 shown in Figs. 30 and 31. 

 For laterals on the flat bot- 

 tomland, risers are provided 

 in the pipe line at intervals 

 depending on the slope, so 

 that the fall from one riser 

 to the next shall not exceed 

 6 inches. An open ditch is 

 maintained directly over the 

 pipe line. 



This system requires only 

 short risers and the ordinary 

 circular valves placed at in- 

 tervals along the pipe line. 

 Where the heads are high 

 and the escaping stream 

 erodes the ditch banks, a 

 short length of pipe is ce- 

 mented on above the valve. 

 The head of water, 1100 gal- 

 lons a minute, is divided be- 

 tween three risers, and the 

 stream from each riser is 

 divided between from 15 to 

 25 furrows, the number de- 

 pending on the soil, the 

 slope, and the length of the 

 furrows. The furrow inter- 

 n^al in 1917 was three and a 

 half feet, but in 1918 the in- 

 terval was reduced to three 

 feet. Where necessary, the 

 field i s cross-leveled for 

 about 50 feet near the head 

 ditches, so that the water 

 flows out into all the fur- 

 rows equally well. 



Fig. 31 illustrates the 

 system used on the sloping 

 lands which border the bot- 



