Irrigation in Orchards 207 



The system of irrigation well adapted to a sandy soil may 

 be a failure with a heavy soil, and the amount of water 

 necessary for the orchard on well drained mesa land might 

 prove injurious to the orchard on poorly drained bottom 

 ground. 



Heavy soils are difficult to irrigate and to keep in good 

 physical condition. The general tendency is for the water 

 to run the soil particles together, thus causing the soil to 

 bake. The heavier soils, composed largely of decomposed 

 shale, sometimes become almost impervious to water. 

 This difficulty may be overcome, to a certain extent, by 

 using deep furrows and placing them far apart. In this 

 way one avoids wetting the surface soil, and it is possible 

 to till before the bottoms of the furrows bake. The 

 ditches may be placed about eight feet apart and should 

 be thrown out with a heavy stirring plow. The head of 

 water should be small and, in some cases, must be run for 

 a considerable length of time. It is doubtful, however, 

 whether it ever pays to run water over seventy-two hours 

 in the same furrows. We have seen water run thirty days, 

 but after the first three days the bottoms and sides of the 

 furrows were so well coated with sediment that very little 

 of the water escaped from them With the heavy soils 

 the water may be run almost any distance. If the rows 

 are extra long, they should be started with a large head of 

 water, and when it has reached the other end of the orchard, 

 the head should be cut down just enough to carry it 

 through. The surface of the heavy soils must not be wet, 

 unless shaded with some crop, and this is the purpose of the 

 deep ditch and the small head of water. Heavy soils that 

 have been plowed must be well settled before an attempt 



