不同浓度NH_4NO_3对高羊茅生长及养分吸收的影响

Effects of Different Concentrations of NH_4NO_3 on Growth and Nutrition Absorption of Festuca arundinacea

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(NH_4NO_3)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。

In order to understand the effects of nitrogen (N) supply (providing NH4^+-N and NO3^--N simultaneously) on the growth and nutrition absorption characteristics of turfgrass, using ammonium nitrate (NH 4NO 3) 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.