Rainfall energy effects on runoff and interrill erosion in effluent irrigated soils

Citation
Ai. Mamedov et al., Rainfall energy effects on runoff and interrill erosion in effluent irrigated soils, SOIL SCI, 165(7), 2000, pp. 535-544
Citations number
36
Categorie Soggetti
Environment/Ecology
Journal title
SOIL SCIENCE
ISSN journal
0038075X → ACNP
Volume
165
Issue
7
Year of publication
2000
Pages
535 - 544
Database
ISI
SICI code
0038-075X(200007)165:7<535:REEORA>2.0.ZU;2-K
Abstract
Seal formation at soil surfaces is significantly affected by raindrop kinet ic energy (KE). Soil sealing enhances runoff and soil erosion. It has been hypothesized that in soils exposed to vain (i) runoff and interrill erosion levels in soils previously irrigated with effluents differ from those in s oils previously irrigated with fresh water (FW), and (ii) that the differen ce in runoff and interrill erosion between the previously irrigated effluen t and FW samples depends on rain KE. The effects of four droplet KE levels (3.6, 8.0, 12.4, and 15.9 kJ m(-3)) of distilled water (DW) on runoff and w ash erosion of four smectitic soils that had been irrigated for many years with fresh water or effluents was studied with a drip-type rain simulator. The soils used were a loamy loess (Calcic Haploxeralf) from Be'er Sheva Val ley, a dark brown sandy clay vertisol (Chromic Haploxerert) from the Pleshe t Plains (vertisol HH), and two dark brown heavy clay vertisols (Chromic Ha ploxerert) from Zevulun Valley (vertisol Y) and Western Galilee (vertisol E ), Israel. For all soils, total runoff and wash erosion values increased wi th the increase in rain KE. Total runoff levels were lower for the FW-irrig ated samples than for the effluent-irrigated soils, except for the highest KE where no differences in runoff between the two types of soils was noted. Conversely, for each soil and each rain KE, wash erosion was higher in the effluent-irrigated samples than in the FW-irrigated ones. Total runoff was affected mainly by changes in rain KE at the lower to medium range of the KE studied. Thus, the effects of irrigation water quality (i.e., effluents vs. FW) on total runoff was pronounced mainly at the low-to-moderate rain K E range; at high rain KE, the effects of irrigation water quality on runoff were negligible. Wash erosion was affected mainly by changes in vain KE at the medium-to-high KE range studied. That wash erosion increased markedly at the high rain KE values, despite the negligible change in runoff level, suggested that for KE greater than or equal to 12.4 kJ m(-3), seal formatio n was completed, and the contribution of runoff in facilitating transport f or the entrained material was secondary to the role of soil detachment in d etermining wash erosion. The dependence of wash erosion (through soil detac hment) on rain KE was greater than its dependence on the quality of the irr igation water that the soil was exposed to in the past (FW vs. effluent).