Performance of Selected Native Ground Cover Species Under Induced Drought Conditions

Abstract

Research related to water stress is becoming increasingly important as the changing climatic scenario is increasing aridity in many parts of the world. In this context, maintaining an acceptable landscape quality using less water has become a challenge. Ground covers are widely used in landscapes to fill spaces hence understanding how water stress affects ground covers is essential for selecting species that can sustain drought. Hence, the objective of this study was to determine the response of three native ground cover species Cynodon dactylon, Desmodium triflorum and Cyrtococcum trigonum for deficit irrigation and to identify the maximally acceptable irrigation deficit at which acceptable landscape quality could be maintained out of these species. A pot experiment was conducted to evaluate the growth performance and visual quality of the three ground cover species under three different water deficit levels (75%, 65% and 55% field capacity) and under 100% field capacity (control). Each treatment consisted of 25 replicates and pots were arranged in Completely Randomized Design. Growth parameters and lawn quality was determined and the quantitative data was analyzed with SAS statistical package and lawn quality was analyzed with non-parametric methods. Induced drought conditions had a significant inhibitory effect on growth parameters and the overall lawn quality of studied species. In all three species shoot and root, fresh and dry weights were significantly reduced with induced drought. However, in C. dactylon, compared to 75% and 65% field capacity levels, at 55% field capacity level fresh and dry weights of shoots and roots were not significantly reduced. Similar observations were recorded with D. triflorum except for shoot fresh weight. In C. dactylon and D. triflorum, overall appearance is reduced after 65 % field capacity level where as in C. trigonum, it was severely affected after 100 % field capacity level. Hence 65 % field capacity level can be considered as the acceptable irrigation deficit for C. dactylon and D. triflorum at which acceptable quality could be maintained. Compared to the other two species, deficit irrigation is not recommended for C. trigonum as it could reduce the visual quality. Journal of Environmental Professionals Sri Lanka: 2015 Vol. 4 No. 2: 25-35