H31G-0701:
Inter-species comparisons in Water use with Different water Irrigation Regimes in a Semi-arid area of Korea-Mongolia Greenbelt Plantation

Wednesday, 17 December 2014
Sungsik Cho1, Byambadorj Ser-Oddamba2, Nyam-Osor Batkhuu2 and Hyun Seok Kim1,3, (1)Seoul National University, Department of Forest Sciences, Seoul, South Korea, (2)National University of Mongolia, Department of Forestry, Ulaanbaatar, Mongolia, (3)Seoul National University, Interdisciplinary Program in Agricultural and Forest Meteorology, Seoul, South Korea
Abstract:
As an effort to mitigate desertification and to restore desert areas in Mongolia, Korea-Mongolia Green Belt was established to develop a 3000 ha plantation in 2006. Two native tree species, Populus sibirica and Ulmus pumila L., have been planted under different irrigation regimes (control, control+2L, control +4L and control +8L) since 2008. To investigate the responses of different tree species to different treatment and the effect of plantation on water balance, intensive field experiments have been carried out in 2013-2014 in Mongolia.

The objectives of our study are 1) to investigate whether different irrigation regimes changed the physiological characteristics of tree species, 2) to quantify transpirations and water balance under different irrigation regimes, and 3) to compare the water-use-efficiencies among species and irrigation regimes.

We used Granier type thermal dissipation sensor, portable photosynthesis analyzer (Li-Cor 6400) and species and site specific allometric equations for transpiration, photosynthetic characteristics and net primary production, respectively. Our preliminary results show that the transpiration rates of P. sibirica increased with the increase of irrigation amount. For examples, the average water consumption of P. sibirica was 1.87kg/tree under control+2L irrigation and 2.97kg/tree at controal+4L irrigation. However, the transpiration rates of U. pumila were not different among different irrigation regimes; the average transpiration of U. pumila at control+2L was 1.1kg/tree compared to 0.89kg/tree at control+4L. But, photosynthetic characteristic showed similar results, which no apparent response under high irrigation regimes. The water use and carbon assimilation of P. sibirica responded to the water irrigation, however, U. pumila did not show any significant response to added water. Our results show different species respond differently to irrigation regimes, and this would lead to different effects on water balance. Therefore, species consideration is necessary for the restoration of desert area.