不同浓度NH4NO3对高羊茅生长及养分吸收的影响

张申 于存申 苗庆选 刘丽萍 刘业萍

摘要：为了解氮素供应状况（同时提供NH+4-N和NO-3-N）对草坪草生长和养分吸收特性的影响，以硝酸铵（NH4NO3）为供试肥料，通过盆栽试验研究了不同氮浓度（0、2.5、10 mmol/L）下高羊茅的生长及养分吸收状况。结果表明，添加外源硝酸铵高羊茅株高、干物质累积量增加，根系平均直径增大，总根长和根表面积降低，根系直径在<0.3 mm和>0.9 mm范围内的根长显著减少;与2.5 mmol/L氮处理相比，10 mmol/L氮浓度植株地上部干物质累积量、根长、根表面积降低。随外源氮浓度的升高，植株地上部氮、钾含量和氮、磷、钾养分吸收量呈上升趋势，地上部氮、钾的分配比例提高;地下部养分含量随氮浓度的增加而增加，氮、钾累积量各处理差异不显著。增加氮浓度单位根长的氮、钾养分吸收量提高，2.5 mmol/L和10 mmol/L氮浓度处理单位根长吸磷量差异不显著。综合分析高羊茅植株地上部和根系生长状况，2.5 mmol/L氮浓度更有利于促进高羊茅植株生长，提高养分吸收量，节约氮资源。

关键词：高羊茅;硝酸铵;地上部;根系;养分吸收

中图分类号：S543+ .906文献标识号：A文章编号：1001-4942（2019）04-0094-06

Abstract In order to understand the effects of nitrogen （N） supply （providing NH+4-N and NO-3-N simultaneously） on the growth and nutrition absorption characteristics of turfgrass， using ammonium nitrate （NH4NO3） as the test fertilizer， a pot experiment was conducted to study the growth and nutrition absorption of Festuca arundinacea at different nitrogen concentrations （0， 2.5， 10 mmol/L）.The results showed that the plant height， dry matter accumulation of shoot and root average diameter of Festuca arundinacea increased with exogenous N supply， while the total root length， root surface area and the length of roots in the range of <0.3 mm and >0.9 mm diameter decreased significantly. Compared with 2.5 mmol/L N treatment， the dry matter accumulation of shoot， total root length and the root surface area of plants decreased with 10 mmol/L N. With exogenous N increasing， the N and potassium （K） contents and the N， phosphorus （P）， K absorption of shoot increased， meanwhile， the proportion of N and K distributed in the shoot increased. The nutrients concentration in the underground of plant increased with the increasing of exogenous N， and no significant differences were found in N and K contents between treatments. The N and K absorption amounts per unit root length increased with the increasing of N supply， and there was no significant difference in the absorption amount of P per unit root length between 2.5 mmol/L and 10 mmol/L N treatments. Comprehensive analysis on the growth of shoot and root， 2.5 mmol/L exogenous N was more conducive to promote the growth and nutrition absorption of Festuca arundinacea， and save N resources.

Keywords Festuca arundinacea;Ammonium nitrate; Shoot; Root; Nutrition absorption

草坪是多年生低矮草本植物在天然形成或人工建植后，經养护管理而形成的相对均匀、平整的草地植被，具有美化生活环境，调节小气候，防止噪音、净化空气等作用，成为城市绿化不可缺少的组成部分[1]。草坪建成后，必须加强养护管理，才能使草坪生长健壮、整齐、美观，达到一定的观赏效果和使用目的[2]。合理施肥是草坪养护的重要技术措施之一，定期并适量地对草坪进行施肥管理，可促进草坪草生长发育，提高草坪质量[3， 4]。