Abstract
An understanding of the water used by vegetation in water limited environment is critical to fully understand water relations of natural areas with vegetation. Such information can be integrated in water management plans to estimate the influence of groundwater abstraction on the vegetation. Trees and shrubs are able to access water from: the upper unsaturated soil profile, the capillary zone of a groundwater store, from nearby streams and rivers. Previous studies have proven that uptake of water by roots is not associated with isotope fractionation. Stable isotope ratios of oxygen and hydrogen were analyzed in groundwater, surface water and plant xylem water. Groundwater samples from the north east part of the country (Enyana and Fair constantia) were most depleted, while samples from the southern part (Guruchas) were enriched. A very weak negative correlation (R2 =0.07), statistically insignificant (P>0.05) relationship has been noted between δ18O values of precipitation and altitude. The estimated depletion rate was 1.3‰ δ 18O per km. The correlation between distance from the coast and δ18O composition of precipitation was negatively weak (R2 =0.29) and statistically significant (P0.05) at roughly 0.09‰ δ 18O depletion per degree. A strong negative correlation (R2 =0.64) existed between δ18O of precipitation and latitude and it was statistically insignificant (P>0.005). The observed high variability in δ 18O and δ2H values of groundwater at different sampling sites was attributed mainly to continental, elevation and amount effect. Both groundwater and xylem water samples plotted below the GMWL, however plant xylem were more depleted in comparison to groundwater.
Kanyama, C (2021). A Study Of Isotopic Composition Of Xylem Water Of Woody Vegetation And Groundwater Along A Precipitation Gradient In Namibia. Afribary. Retrieved from https://tracking.afribary.com/works/a-study-of-isotopic-composition-of-xylem-water-of-woody-vegetation-and-groundwater-along-a-precipitation-gradient-in-namibia
Kanyama, Cristofina "A Study Of Isotopic Composition Of Xylem Water Of Woody Vegetation And Groundwater Along A Precipitation Gradient In Namibia" Afribary. Afribary, 21 Apr. 2021, https://tracking.afribary.com/works/a-study-of-isotopic-composition-of-xylem-water-of-woody-vegetation-and-groundwater-along-a-precipitation-gradient-in-namibia. Accessed 24 Nov. 2024.
Kanyama, Cristofina . "A Study Of Isotopic Composition Of Xylem Water Of Woody Vegetation And Groundwater Along A Precipitation Gradient In Namibia". Afribary, Afribary, 21 Apr. 2021. Web. 24 Nov. 2024. < https://tracking.afribary.com/works/a-study-of-isotopic-composition-of-xylem-water-of-woody-vegetation-and-groundwater-along-a-precipitation-gradient-in-namibia >.
Kanyama, Cristofina . "A Study Of Isotopic Composition Of Xylem Water Of Woody Vegetation And Groundwater Along A Precipitation Gradient In Namibia" Afribary (2021). Accessed November 24, 2024. https://tracking.afribary.com/works/a-study-of-isotopic-composition-of-xylem-water-of-woody-vegetation-and-groundwater-along-a-precipitation-gradient-in-namibia