Optimal water and fertilizer applications improve growth of Tamarix chinensis in a coal mine degraded area under arid conditions

Coal-mined areas are often associated with hostile environmental conditions where the scarcity of water and key nutrient resources negatively affect plant growth and development. In this study we specifically addressed how different combinations of water (W), nitrogen (N) and phosphorus (P) might affect morpho-physiological and biochemical attributes of a native shrub species, Tamarix chinensis,grown on coal mine spoils. Our results show that under greenhouse conditions the application of moderate-to-high doses of W, N and P considerably improved growth-associated parameters (i.e. plant height, stem diameter, dry weight), as well as gas-exchange parameters, photosynthetic pigment contents and leaf water status ofT. chinensis. Under field conditions high W and low N, P doses led to significant increases in plant growth-associated traits, gas-exchange parameters and leaf water status. Plant growth was generally higher under greenhouse conditions mainly because seedlings faced multiple stress when growing under field conditions. Low W-regime, regardless of N-P additions, improved osmotic adjustments in leaf tissues and also boosted the activity of several antioxidant enzymes to reduce the oxidative stress associated with W scarcity under greenhouse conditions. Importantly, our study shows how maximum growth performance ofT. chinensisunder field conditions was achieved at W, N and P doses of 150 mm year(-1), 80 kg ha(-1)and 40 kg ha(-1), respectively. Our findings suggest that achieving optimal rates of W, N and P application is crucial for promoting the ecological restoration of coal-mined areas withT. chinensisunder arid environmental conditions.

Automated summary

Coal-mined areas with hostile environmental conditions negatively affect plant growth. This study specifically addressed how different combinations of water, nitrogen, and phosphorus might affect attributes of a native shrub species. Results showed that moderate-to-high doses of W, N, and P improved growth-associated parameters and gas-exchange parameters, with optimal growth achieved at specific doses of W, N, and P. Achieving optimal rates of W, N, and P application is crucial for restoring coal-mined areas under arid environmental conditions.