University of Khartoum/ M of Social Development Khartoum, Khartoum, Sudan
Background/Question/Methods:
In light of rising CO2 and its consequences of drought and soil health, the interaction effects of elevated carbon dioxide e[CO2] water stress and nutrients will have an effect on the adaptation of acacias (Hashab) tree to future climate scenarios. For the dryland regions, and according to its fragility, the scenarios include the rising occurrences of drought and degradation of soil fertility. This study aims at investigating the interactive effects of eCO2, water stress and soil type on growth parameters of Acacia senegal seedlings. Seedlings of 7 days old were grown in silt and sand soils and then exposed to eCO2 (600-800 ppm) and ambient CO2 (≤400 ppm) using Free Air CO2 Enrichment (FACE) technique and irrigated by well watered (every day) and water stress (every two days) for four weeks. Seedling's height, leaf number, length of tab root, seedling's C%, N% and H% and seedling's dry weight were measured.
Results/Conclusions:
The data showed that interaction effect of eCO2 and soil type was significant on seedling's dry weight, similarly a significant interaction effect of irrigation interval and soil type was found in seedling's dry weight. Also, a significant interaction effect of irrigation interval and soil type was found on leaves' dry weight. Likewise, a significant interaction effect of irrigation interval and soil type was found on leaves' nitrogen content, also, a significant 3-way interaction effect of eCO2, irrigation interval and soil type was found on leaf hydrogen content. While, interaction effect was not observed on seedling height, leaf number and tap root length. The results led to the conclusion that generally, under water stress and nutrient-limited conditions the plant interactive responses to eCO2 were decreased and may have a negative acclimation impact.
