Effects of soil compaction on growth and physiological characteristics of azadirachta excelsa seedlings

Abstract

Urban landscape trees have always been very much exposed to the stresses of soil compaction. Trees in such condition need high flexibility in both morphological and physiological attributes to survive well. This study was conducted to determine the effect of soil compaction on Azadirachta excelsa seedlings by imposing different levels of compacted medium with bulk density at 1.2, 1.4 and 1.6 g cm-3. Growth and physiological characteristics were assessed and repeated measures analysis was used to analyze the differences between treatments. The results showed that the seedlings were seen struggling to survive but still sprouting new shoots even after showing dying symptom. Significant decrease in leaf elongation also occurred in this experiment resulting from root damage thus initiated reducing physiology performance in leaf traits. However, biomass data showed persistent relation towards root sensitivity of the system architecture. Gas exchange attributes were also found to decrease significantly between treatments but not for other water related parameters such as predawn and midday water potential, hydraulic conductance and water use efficiency. It was decisively found that this species is partially tolerable towards soil compacted condition due to its ability to resist permanent damage and stress avoidance.