Characterizing infiltration and internal drainage of South African dryland soils. Issue 3 (22nd July 2016)

• Record Type: Journal Article
• Authors: Mavimbela, Sabelo S.W.; van Rensburg, Leon D.
• Is Part Of: Earth surface processes and landforms. Volume 42:Issue 3(2017)
• Page Start: 414
• Page End: 425
• Publication Date: 2016-07-22
• Subjects: aeolian sands -- steady infiltration rate -- soft calcium carbonate -- floodplain soil types -- Wilcox drainage model; Geomorphology -- Periodicals; 551.4
• DOI: 10.1002/esp.3991
• Languages: English
• ISSNs: 0197-9337

Abstract

Abstract: Surface infiltration and internal drainage properties of five soil types from arid drylands of South Africa were studied under double ring infiltrometer, rainfall simulation plots (1 m 2 ) and instantaneous drainage plots (9 m 2 ). Changes in soil water content during 40 minute rainfall simulation for a rainstorm with average intensity of 1.61 mm min −1 and 30 day drainage period were measured at various depths by 1.5 m long capacitance soil water measuring (DFM) probe. Different ( P < 0.05) mean surface steady infiltration rate ranged from 0.05 to 4.47 mm min −1 and had a negative power relationship ( R 2 = 0.65) with horizon clay plus fine silt content. Power regression ( R 2 ≥ 86%) described rainstorm infiltration and obtained steady rates within an average time of 15 minutes. Mean total infiltrated soil water content was lowest ( P < 0.05) from surface horizons with either 47.7% clay plus fine silt content or bulk density of 1.91 g cm −3 and exchangeable sodium of not less than 44 mg kg −1 . Surface horizons with lower surface bulk density and total sand fraction of more than 72% had infiltrated depth and mean total infiltrated soil water content up to 40 cm deeper and 0.55 mm mm −1 greater, respectively. Drainage rate at drained upper limit calculated from the Wilcox drainage model ( R 2 ≤ 0.97%) was 0.2 mm day −1 or less were from underlying horizons with either clay plus fine silt of 45% or soft calcium carbonate. Higher drainage rate with accumulative drainage amount greater than 60 mm were from soil profile horizons with clay plus fine silt content of less than 20% and above unity steady infiltration rates. Rainstorm infiltration and drainage rates was shown to depend on permeability and coarseness of the respective soil surface and subsurface horizons; a phenomenon critical for harnessing rain and flood water to recharge groundwater. Copyright © 2016 John Wiley & Sons, Ltd.