Study on Nitrogen Effect to Growth and Physiological Characteristics of Zoysia japonica Under Traffic Stress

Use the biennial Zoysia japonica in field as the research object, the experiment was exposed by randomized complete-block design, after being treated by traffic stresses which was made by traffic machine, and applying nitrogenous fertilizer, the growth indicators of turfgrass density, height and the aboveground biomass of Z. japonica and the physiological indexes of leaf relative conductivity, free proline content, MDA content and soluble sugar content were determined to analyze the correlation between recovery growth of Z. japonica and nitrogen level under traffic stresses. The results showed that the turf density decreased, the plant height lowed and the aboveground biomass reduced under the traffic stresses, but applying nitrogenous fertilizer have different effects on Z. japonica, N₁ treatment improved the tillering of Z. japonica, which make the density increased, the height growth and the aboveground biomass relative increased. After 30 days recovery growth, the effects of traffic stresses on Z. japonica grass still existed, however, the recovery growth of the density, height, aboveground biomass of Z. japonica were faster relatively, which was significantly different from that under N₂ treatment. The relative conductivity, proline content, MDA content and solubility sugar content of Z. japonica leaf have a change increasing trend with traffic stresses increased, but the total chlorophyll content have a change decreasing trend. By applying nitrogen, with nitrogen level increasing, the change of index of Z. japonica leaf have a trend as same as traffic stresses increased, N₂ treatment have significant effects on relative conductivity, free proline content, MDA content and soluble sugar content of Z. japonica leaves under no and moderate traffic stress, which increased the damage of Z. japonica. In the recovery growth period, the change of the physiological indexes relatively reduced under traffic stresses, the effects of stresses were not obvious. By applying nitrogenous fertilizer, the difference was significant between moderate, heavy nitrogen treatment with CK, which shows that applying proper amount nitrogen can improve traffic-resistance of Z. japonica.