RESULTS Ai^iy DISCUSSION 



All granitic soils sampled in this study fell within the sand and loamy sand tex- 

 tural classes. Sand content of the surface soil of the plots ranged from 80 to 95 per- 

 cent and averaged 89 percent. Clay content ranged from 2.4 to 4.5 percent and averaged 

 5.5 percent. With few exceptions soil bulk density was less than 1.6 g./cc; and 

 generally less than 1.4 g./cc. The infiltration capacity of such coarse, porous soils 

 is excellent in the absence of water repellency. However, water repellency was encoun- 

 tered on most of the plots, varying in degree from a barely perceptible slowing of the 

 wet front to a virtually complete halting of the wet front. WTiere a high degree of 

 water repellency was present, its distribution in the soil profile ranged from a few 

 isolated patches to a thick, continuous layer. 



"Wettlxtg Pa.ttex*xi.s 



The wetting pattern in the soil of each plot was exposed by digging a trench across 

 the middle of the plot after water had been applied for 30 minutes. Although no two 

 wetting patterns were exactly alike, they could be classified into eight general ty-pes , 

 depending on size, continuity, and location of water-repellent zones (fig. 1). 



Pattern 1 is the typical wetting pattern of homogeneous, wettable soils. This 

 pattern was found only in openings devoid of vegetation and litter. 



Pattern 2 occurred where the soil surface was covered by litter. Live plants were 

 usually present. The wet front is irregular because the soil is not homogeneous. The 

 irregularity is due primarily to variations in soil porosity, but it is believed that 

 variations in soil wettability are partially responsible in some cases. 



5 



