השפעת כוחות יניקה על היווצרות נגר על-קרקעי בקרקע מדברית

Translated title of the contribution: Effect of soil suction on runoff generation in arid soil

איל זקס, שרה פריינטה

Research output: Contribution to journalArticlepeer-review

Abstract

Raindrops, which hit bare soil, generate seal formation on or near the soil surface. When rain intensity exceeds the infiltration rate, runoff is generated. This study investigates the effect of capillary forces of the soil on seal formation in arid soils, using a rain simulator at the laboratory. Soil for rain simulator experiments was taken from a south-facing slope at the "Halukim" ridge in the northern Negev, Israel. The soil was collected from depths of 0-1 cm and 1-5 cm, and then placed within boxes (116 cm long and 55 cm wide) in the laboratory in the same order as that of the field. Representative surface stones were collected from the field and scattered randomly on the soil surface. In some of the boxes, soil, 5 cm in depth, was placed on a geotechnical sheet on a metal screen, while in others, soil of 5 cm depth was placed on a Terzaghi filter. The rain simulator sprinkling intensity was 18 mm/hour. Soil moisture was measured during sprinkling using TDR sensors and continuous weighing of the soil boxes. A significant correlation was found between the antecedent moisture content and the final infiltration rate in the boxes without a Terzaghi filter, but the boxes with this filter showed no correlation. This indicates that processes which involve creation and destruction of aggregates and crusts affect the hydraulic conductivity of seal formation even after several rain events only for the boxes without a filter. Hydrological features of soil seal formation were stabilized after 100-200 mm of watering without filter, while with a filter such features were stabilized after less than 50 mm. The clay content in crust developed in boxes without filter was significantly greater than that created with filter. It is conceivable therefore that there is a suction of thin material from the surface when capillary pressure is activated, causing a depletion in the thin material of the surface crust which may result in sub-surface sealing (washed-in layer)
Translated title of the contributionEffect of soil suction on runoff generation in arid soil
Original languageHebrew
Pages (from-to)79-94
Number of pages16
Journalאופקים בגאוגרפיה
Volume93
StatePublished - 2017

Bibliographical note

כולל תקציר באנגלית

IHP Publications

  • ihp
  • הדמיה
  • Imaging systems
  • גשם
  • Rain and rainfall
  • סחף
  • Soil erosion
  • קרומי קרקע
  • מערכות אקולוגיות
  • Biotic communities
  • מדבר
  • Deserts
  • קרקע -- היבטים גיאולוגיים וחקלאיים
  • Soils
  • נגר עלי
  • Runoff

RAMBI Publications

  • RAMBI Publications
  • Runoff -- Israel
  • Desert soils -- Israel
  • Soil crusting -- Israel

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