不同施肥方法对马来沉香和土沉香苗期根系生长的影响

以珍贵树种马来沉香、土沉香1年生播种苗木为材料进行试验,研究指数施肥、平均施肥对2种沉香苗期根系生长动态及对N的响应特征。结果表明,经氮素处理的马来沉香、土沉香的根系生物量、根系长度、根系表面积、根系平均直径、根体积等指标均显著高于对照处理(P<0.05)。经指数施肥处理的苗木根系生长及各形态指标均高于平均施肥处理。同一时期在相同施肥处理方式下,马来沉香苗根系生长及根系形态指标值均高于土沉香。洛伦兹模型对不同施肥方法处理下马来沉香、土沉香苗木生长指标与根系生物量进行拟合,具有较高的R²(0.95-0.99)和较低的RSMD(0.538-2.352);抛物面模型对不同施肥方法处理下马来沉香、土沉香苗木生长指标与比根长进行拟合,具有较高的R²(0.92-0.99)和较低的RSMD(3.218-6.692)。

Growing dynamic root system of Aquilaria malaccensis and Aquilaria sinensis seedlings in response to different fertilizing methods

Nitrogen is one of the most important limiting nutrients during tree growth. In this paper, the effects of nitrogen treatments with the exponential fertilization method, traditional fertilization method(mean fertilization) and non-fertilization on the total biomass and morphology parameters in roots of one-year-old Aquilaria malaccensis and Aquilaria sinensis seedlings were studied during a five-month period. The results suggested that N supply could significantly increase the root total biomass and root morphology parameter such as root length, root surface-area, root diameter,root volume and specific root length(P<0.05). The root total biomass and root morphology parameter of the two Aquilaria seedlings from the exponential fertilization treatment were higher than those showed from the mean fertilization treatment. The conclusion is that the plants of Aquilaria malaccensis and Aquilaria sinensis treated with exponential fertilization can reach the highest growth rate. The Lorentzian model as a multi-variable nonlinear model was firstly applied to the simulations using both base diameter and height, and performed the best fit to total root biomass in the two species with the highest correlation coefficients (R²,0.95-0.99) and smallest root mean squared deviations (RMSD,0.538-2.352) among all the examined models. The Paraboloid model accurately simulated base diameter,height, and performed the best fit to specific root length in the two species with the highest correlation coefficients (R²,0.92-0.99) and smallest root mean squared deviations (RMSD,3.218-6.692) among all the examined models.