The soil water regime of an arid grassland (eragrostis eriopoda benth.) community in central australia
✍ Scribed by R.E. Winkworth
- Publisher
- Elsevier Science
- Year
- 1970
- Weight
- 665 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0002-1571
No coin nor oath required. For personal study only.
✦ Synopsis
Precipitation and soil moisture contents through the profile of a red earth soil supporting an arid tussock grassland were recorded for two years near Alice Springs, N.T., Australia. There were six significant periods of soil water recharge, followed by renewed growth of the grassland and withdrawal of soil moisture from the whole profile to very low contents equivalent to an average soil water potential of -120 bar. The low minimum water contents were relatively stable through all dry periods. Water stored in the whole soil profile at contents exceeding the minimum values was calculated and progressive changes in storage during the drying cycles were used to calculate evapotranspiration rates. Average rates ranged from 2.1 mm/day to 0.8 mm/day. The water balance of this community, calculated from the equation: initial soil storage + rainfall = final soil storage + run-off + direct evaporation showed that over the whole period about 52% of rainfall entered soil storage, ca. 28 % was lost to run-offand 20 % was directly evaporated. Plant growth was not measured and hence, the observed variation in peak evapotranspiration rates cannot be explained adequately. The lack of information on the relationship of evapotranspiration rates to plant cover in the arid zone is a serious handicap to the development of computerized water balance models which have important practical significance for estimating forage production on the broad expanses of Australian rangelands.