 |
| Titel |
Eucalyptus water use greater than rainfall input - possible explanation from southern India |
| VerfasserIn |
I. R. Calder, P. T. W. Rosier, K. T. Prasanna, S. Parameswarappa |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 1, no. 2 ; Nr. 1, no. 2, S.249-256 |
| Datensatznummer |
250000144
|
| Publikation (Nr.) |
 copernicus.org/hess-1-249-1997.pdf |
|
|
|
|
|
| Zusammenfassung |
Hydrological and silvicultural studies carried out
in southern India on the effects of plantations of Eucalyptus and other
fast growing exotic tree species have determined the impacts of these plantations
on water resources, erosion, soil nutrient status and growth rates at sites
of differing rainfall and soil depth in Karnataka. Whilst providing new
information on these issues, the studies also raised two important questions:
what was the explanation for the anomalous result that the water use of
3400 mm from Eucalyptus plantations at Hosakote over a three year period
exceeded the rainfall of 2100 mm over the same period and why were growth
rates of woodlots on most farmer's fields higher than those of plantations
on land owned by the Karnataka Forest Department? The records of the soil
moisture depletion patterns under these plantations from the day of planting
provide the basis for the answers to both questions: i) whilst roots are
penetrating into deeper soil layers, they are able to extract from a reservoir
of water additional to that available from the rainfall each year, ii)
farmer's land on which short rooted agricultural crops have been grown
previously is likely to have a much higher soil water status than land
previously under forest or scrub vegetation. These new studies have also
established that the development of the drying front under the
Eucalyptus camaldulensis plantations is very rapid, indicating average root extension
rates in excess of 2.5 m per year, whilst those under Tectona grandis and
Artocarpus heterophyllus advanced at approximately half the rate. These
results have obvious implications for the long term sustainability of growth
rates from these plantations and the recharge of groundwater.
The authors
believe that this study may be the first to report neutron probe soil moisture
depletion observations, from the date of planting, beneath tree plantations
in a dry climate. The extent to which the roots were able to penetrate
raises the question of whether other studies, which have estimated water
use from soil moisture observations in dry climates, may have seriously
underestimated both the actual soil moisture depletion and the water use
through having soil moisture measurements located to insufficient depth. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|