704 SOILS: PROPERTIES AND MANAGEMENT 



uted from the furrows by percolation and by capillary 

 movement. Percolation causes the accumulation of 

 water under- the upper end of the furrows ; capillary move- 

 ment distributes the water laterally as well as. downward, 



FIG. 79. Diagrams showing the relative rate of movement of water 

 from irrigation furrows into clay loam (left), and sandy loam 

 (right), after different periods of time. 



and its rate determines the distance between the furrows. 

 The downward l movement is much more rapid than the 

 lateral movement, and both are very irregular, depending 

 on the nature and structure of the soil. Ordinarily the 

 furrows are relatively close together, to give greater 

 uniformity in distribution. In corn, potatoes, berries, 

 garden vegetables, and crops of similar character, a furrow 

 is placed in each row, or at least in every other row as is 



1 Widtsoe, J. A., and McLaughlin, W. W. The Movement 

 of Water in Irrigated Soils. Utah Agr. Exp. Sta., Bui. No. 

 115. 1912. Also, Loughridge, R. H. Distribution of Water 

 in the Soil in Furrow Irrigation. U. S. D. A., Office Exp. Sta., 

 Bui. No. 203. 1908. 



