Soil-water behaviour of sandy soils under semi-arid conditions in the Duero Basin (Spain)

This paper examines the soil-water behaviour of sandy soils representative of a broad area in the Duero river basin (Spain), with semi-arid bioclimatic characteristics. Soil-moisture measurements of the first 25 cm of soil profile were taken using time domain reflectometry (TDR) methodology. The infiltration process was studied by means of field experiments combining rainfall simulations and TDR techniques. Finally, a set of hydrodynamic variables was calculated in the laboratory (i.e. available soil-water content, soil-water-retention curves and hydraulic conductivity). The average available soil-water content is 0·07 cm3 cm−3, in accordance with the predominance of the sandy textural fraction (≅85%). The rainfall simulation experiments show that infiltration prevails over overland flow, with a steady-state infiltration rate higher than rainfall application (40mmh−1) in most cases; a low water-retention capacity was also observed. The evolution of soil-moisture over time indicates a close dependence on intra-annual rainfall variability due to the low water-retention capacity of sandy soils. With a maximum water-storage capacity of around 0·18 cm3 cm−3, the soils studied show high sensitivity to dry spells and may remain with <50% of the available soil-water content for several months during the year.

[1]  Jean Poesen,et al.  The hydrological response of soil surfaces to rainfall as affected by cover and position of rock fragments in the top layer , 1990 .

[2]  Artemi Cerdà,et al.  Design and operation of a small and portable rainfall simulator for rugged terrain , 1997 .

[3]  J F Reynolds,et al.  Biological Feedbacks in Global Desertification , 1990, Science.

[4]  Nunzio Romano,et al.  Effectiveness of using pedo-transfer functions to quantify the spatial variability of soil water retention characteristics , 1997 .

[5]  M. Bertiller,et al.  Climatic controls of soil moisture dynamics in an arid steppe of northern Patagonia, Argentina , 1997 .

[6]  G. Topp,et al.  Measurement of Soil Water Content using Time‐domain Reflectrometry (TDR): A Field Evaluation , 1985 .

[7]  E. Malek,et al.  Dew contribution to the annual water balances in semi-arid desert valleys , 1999 .

[8]  S. Zegelin,et al.  Improved field probes for soil water content and electrical conductivity measurement using time domain reflectometry , 1989 .

[9]  J. Poesen,et al.  Evaporation losses from bare soils as influenced by cultivation techniques in semi-arid regions , 2000 .

[10]  Artemi Cerdà,et al.  Soil hydrological response under simulated rainfall in the Dehesa land system (Extremadura, SW Spain) under drought conditions , 1998 .

[11]  D. R. Bhumbla,et al.  Relationship of texture to some important soil moisture constants , 1968 .

[12]  M. Arroyo,et al.  Ecology and Biogeography of Mediterranean Ecosystems in Chile, California, and Australia , 1995, Ecological Studies.

[13]  A. Williams,et al.  Soil moisture variability in a semi-arid gully catchment: implications for runoff and erosion control , 1998 .

[14]  C. Fayos.  The roles of texture and structure in the water retention capacity of burnt mediterranean soils with varying rainfall , 1997 .

[15]  William K. Lauenroth,et al.  Bare‐Soil Evaporation Under Semiarid Field Conditions , 1999 .

[16]  D. K. Cassel,et al.  Practical considerations for using a TDR cable tester , 1994 .

[17]  N. Fohrer,et al.  Changing soil and surface conditions during rainfall , 1999 .

[18]  Patrick Andrieux,et al.  Infiltration characteristics of soils in Mediterranean vineyards in Southern France , 1998 .

[19]  D. H. Yaalon,et al.  Two Causes for Runoff Initiation on Microbiotic Crusts: Hydrophobicity and Pore Clogging , 1999 .

[20]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[21]  W. E. Larson,et al.  Estimating soil water retention characteristics from particle size distribution, organic matter percent, and bulk density , 1979 .

[22]  V. Castillo,et al.  Spatial patterns and temporal stability of soil moisture across a range of scales in a semi‐arid environment , 2000 .

[23]  M. Bertiller,et al.  Precipitation and landscape related effects on soil moisture in semi-arid rangelands of Patagonia , 1996 .

[24]  F. Ingelmo,et al.  Hydric properties of some Spanish soils in relation to their rock fragment content: implications for runoff and vegetation , 1994 .

[25]  Ali Fares,et al.  Soil Water Components Based on Capacitance Probes in a Sandy Soil , 2000 .

[26]  Costas Kosmas,et al.  The effect of rock fragments on wheat biomass production under highly variable moisture conditions in Mediterranean environments , 1994 .

[27]  A. Cerdà.  Seasonal variability of infiltration rates under contrasting slope conditions in southeast Spain. , 1996 .

[28]  J. Poesen,et al.  The effect of water vapour adsorption on soil moisture content under Mediterranean climatic conditions , 1998 .

[29]  A. C. Bolinches.  Factores y variaciones espacio-temporales de la infiltración en los ecosistemas mediterráneos , 1995 .

[30]  R. Berndtsson,et al.  Spatial variability of infiltration in a semi-arid environment , 1987 .

[31]  Steve Twomlow,et al.  The influence of tillage on semi-arid soil-water regimes in Zimbabwe. , 2000 .

[32]  S. P. PERIASWAMY,et al.  ESTIMATING AVAILABLE WATER‐HOLDING CAPACITY OF WESTERN NIGERIAN SOILS FROM SOIL TEXTURE AND BULK DENSITY, USING CORE AND SIEVED SAMPLES , 1985 .