干旱区生态环境知识资源中心

This paper reveals the consequences of water extraction by Eucalyptus camaldulensis as compared to native Acacia nilotica Del., Albizia procera [Roxb.] Benth and Azadirachta indica grown on cultivated lands. Eucalyptus, due to its fast growth rate and wide adaptability to prevailing environmental conditions, was planted ruthlessly without any concern for its impact on soil deterioration and harm to ground water. The aim of this study was to investigate whether Eucalyptus is of any importance in conserving water and consequently its impact on the depletion of ground water resources. The four species were grown in pots in a green house. Water consumption by one year old Eucalyptus [149.27 L] was almost twice that of by Albizia [82.84 L] and more than three times that of by Acacia [58.30 L], and Azadirachta [51.57 L].

Significant variation between the species was observed for biomass produced. When this was translated into water use efficiency [WUE], it was found as 0.32 g L-1, 0.48 g L-1, 0.16 g L-1 and 0.77 g L-1 while transpiration coefficient [TC] was 1042 L kg(-1), 872 L kg(-1), 1951 L kg(-1) and 739 L kg(-1) for Acacia, Albizzia, Azadirachta and Eucalyptus respectively. It is important to control evaporation losses [44-69% of total irrigation] which may be much higher than transpiration. Increased water use uptake by Eucalyptus may lead to reduction and scarcity of aquifer resources for irrigated agriculture in arid and semiarid climates. Although water use efficiency of any species is also important, but environmental concerns about the amount of water consumed by these species are also considered most important.