Effects of different concentrations of NO₃^–-N on the growth and nutrients uptake of Festuca arundinacea

In order to clarify the growth and nutrients absorption characteristics of Festuca arundinacea under different NO₃^–-N levels and to determine the NO₃^–-N concentration suitable for its optimal growth, Ca(NO₃)₂ was used as an exogenous nitrogen source in this study. The growth and nutrients uptake response to different concentrations of NO₃^–-N (0, 5, 10, 15, 20 mmol·L^–1) were studied under the conditions of quartz sand pots cultivation. The results showed that exogenous NO₃^–-N had significant effects on the growth of both shoots and roots of Festuca arundinacea. With increased NO₃^–-N concentrations, the plant height and dry matter accumulation of the shoots first increased and then decreased. The root dry matter accumulation, root length, and root surface area decreased with the increase in NO₃^–-N concentration, and the mean root diameters were not statistically different between the treatments. Increasing the concentrations of NO₃^–-N could increase phosphorus (P) concentrations and P uptake, and the suitable concentrations of NO₃^–-N could promote the absorption and accumulation of nitrogen and potassium in the shoots. The optimal concentration of NO₃^–-N for Festuca arundinacea’s growth was 4.3～18.2 mmol·L^–1. From the above results, 4.3 mmol·L^–1 NO₃^–-N can be used as a reference for the rational level of N fertilization for Festuca arundinacea conservation and management.