Factors Influencing Infiltrability of Semiarid Mountain Slopes
Journal of range management
The objective of tbis research was to determine the effects of selected vegetation, soil, rock, and slope variables on lnflltration of semiarid rangelands with slope gradients ranghtg from g-70%. Analyses were made on 2 sets of data collected a year apart in the Guadalupe Mountains of New Mexico and consisted of Pearson and partial correlation analysis of the dependent infiltration variables and independent site variables. In addition, htfiltratioa was regressed against uncorreiated factors
... reiated factors produced by factor analysis. Vegetal cover and biomass strongly ifiuenced infiltration. The relative importance of grasses, shrubs or litter was dependent on their respective abundance, especially grass. Soil depth also limited infiltration especially as soil water storage became satisfied. Infiltrability was negatively correlated with rock cover and the smallest rock size fragments were the most negatively related. When the effects of vegetal cover and slope were removed (using partial correiation analysis) however, the median sized rock fragments (26-150 mm) were positively related to infiltrabiiity, and the smailest rock fragements (2-12 mm) were negatively related. Partial correl8tion analysis also suggested 8 positive correlation between htfiltrabigty and slope gradient. Key Wordsz soil water, htfihration, rangeland hydrology An understanding of basic hydrologic processes on rangeland is critical for effective range watershed management. The infiltration process fundamentally influences rangeland hydrology; thus, knowledge of factors that influence infiltration is important. Many studies have assessed the influence of soil and vegetation factors on rangeland infiltration. Few, however, have evaluated semiarid rangelands and none to our knowledge have included very steep slopes in their study. Results of these studies have been variable depending on the characteristics of the study area (Branson et al. 1981) .