Estimating episodic recharge under different crop/pasture rotations in the Mallee region. Part 2. Recharge control by agronomic practices

Much environmental degradation, including salinity in the Mallee region of southeastern Australia, is associated with the loss of native vegetation and increased recharge. As a result, various agronomic practices have been proposed to reduce groundwater recharge. This study was conducted to evaluate...

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Veröffentlicht in:Agricultural water management 1999-11, Vol.42 (2), p.237-249
Hauptverfasser: Zhang, L, Dawes, W.R, Hatton, T.J, Hume, I.H, O'Connell, M.G, Mitchell, D.C, Milthorp, P.L, Yee, M
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Sprache:eng
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Zusammenfassung:Much environmental degradation, including salinity in the Mallee region of southeastern Australia, is associated with the loss of native vegetation and increased recharge. As a result, various agronomic practices have been proposed to reduce groundwater recharge. This study was conducted to evaluate the impact of these practices on recharge, in particular episodic recharge. A biophysically based model (WAVES) was used to estimate recharge rates under some typical crop and pasture rotations in the region using long-term meteorological data. Results show that: (1) recharge just below the root zone was episodic and that just 10% of annual recharge events contributed over 85% of long-term totals. Management options such as incorporating lucerne and deep-rooted non-fallow rotations can reduce both, mean annual recharge, and the number of episodic events, but not eliminate recharge completely; (2) winter fallows increased soil-water storage and some of the additional water was stored in the lower portion of the root zone or below it. This can increase the risk of recharge to groundwater system; (3) changes in land management may take a considerable period of time (>10 years) to have any noticeable impacts on recharge; and (4) recharge under lucerne was ≈30% of that under medic pasture.
ISSN:0378-3774
1873-2283
DOI:10.1016/S0378-3774(99)00034-7