氮素对践踏草坪生理生长特性的影响

以大田2年生结缕草草坪为研究对象，采用完全随机区组设计，通过模拟践踏和施氮处理后，测定草坪草密度、株高、地上生物量等生长指标和叶片相对电导率、游离脯氨酸含量、丙二醛含量和可溶性糖含量等生理指标，分析草坪草受践踏和恢复生长与氮素水平之间的相关关系。结果表明：践踏后结缕草草坪密度减小、株高降低、地上生物量减少；施氮肥会对结缕草产生不同影响，N₁处理可促使其分蘖，使密度相对增大，株高和地上生物量也相对增加。待恢复生长30 d后，践踏的影响还存在，N₁处理下，草坪密度、株高和地上生物量的恢复生长相对较快，与N₂处理之间差异显著；结缕草叶片的相对电导率、游离脯氨酸含量、丙二醛含量、可溶性糖含量随践踏胁迫程度的增加有递增趋势，总叶绿素含量有相对递减趋势。施用氮素后，各生理指标的变化与受践踏程度增加的变化一致，N₂对无践踏和中度践踏下草坪叶片相对电导率、游离脯氨酸含量、MDA含量、可溶性糖含量影响显著，使草坪的损伤程度加大。恢复期各生理指标在践踏后草坪的变化相对减小，胁迫影响的作用不明显；施用氮素后，N₁在中度和重度践踏与不践踏（CK）差异显著。由此表明，N₁处理可以提高草坪草的抗践踏性。

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.