Factors Influencing Infiltrability of Semiarid Mountain Slopes

Abstract

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 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).

Statistical analysis and modelling of surface runoff from arable fields in central Europe

“…The threshold indicated that small stone contents, which usually also are associated with small and rounded stones, did not exhibit this effect. In this case it can be expected that the small stones are embedded within the soil matrix and may even decrease infiltration rates (Wilcox et al, 1988). This threshold agrees with the calculation of soil erodibility in the revised universal soil loss equation, which also uses a threshold of 10 % for the consideration of stones (Roemkens et al, 1997).…”

Runoff generation in a degraded Andean ecosystem: Interaction of vegetation cover and land use

“…These degraded areas are characterized by soil truncation and often by outcrops of weathered bedrock. These structurally degraded soils limit soil biological activity and plant establishment by reducing plant root development and growth, and by reducing water and nutrient cycling and storage capacity (Wilcox et al, 1988;McGinty et al, 1995). Degraded land has generally a low vegetative cover (18% ± 23.5), and low soil organic matter content (1% ± 1).…”

Mound development as an interaction of individual plants with soil, water erosion and sedimentation processes on slopes

“…since the plant colonized the site). Several authors have underlined the lack of data concerning the individual response of the most representative species of the Mediterranean matorral to water erosion processes and also the relative importance of plant components in water erosion control (Rickson and Morgan, 1998;Wilcox et al, 1988;Cabezas et al, 1990;Sala and Calvo, 1990). Furthermore, the majority of existing studies on vegetation±erosion relationships in the Mediterranean region have been carried out in the short term, that is during specific natural or simulated rainfall events.…”