Adopting a portable ground penetrating radar (GPR) with 1000 MHz antenna, we detected the root system of Larix gmelinii in two 10 m ×10 m plots at Mao'ershan Experiment Forest Farm, Heilongjiang Province. The GPR detection results were compared with field empirical data, and analyzed the identification rate of GPR techno-logy on different root diameter sizes (0.2-0.5, 0.5-1.0, 1.0-2.0, 2.0-3.0, 3.0-4.0, 4.0-5.0, and >5.0 cm) of L. gmelinii and soil depths (0-10, 10-20, and 20-30 cm). The results showed that for roots with diameter greater than 2.0 cm, the identification rate of 1000 MHz GPR reached 49.8%, with the maximum time interval, total time interval, maximum amplitude area, and total amplitude area of GPR reflection waves being significantly positively correlated with root diameter. For roots with diameter <2.0 cm, the identification rate of GPR was extremely low (6%). As the soil depth increased, root identification rate showed a trend of increasing and then decreasing. The root identification rate was highest at 31.4% in the 10-20 cm soil layer and lowest at 10.2% in the 0-10 cm soil layer. GPR could effectively identify root systems of L. gmelinii with larger diameters (>2.0 cm), and showed an optimal identification rate for root systems in the 10-20 cm soil layer. However, its detection ability for small dia-meter root and deep root of L. gmelinii should be improved.
采用1000 MHz天线的便携式探地雷达(GPR)系统对中国黑龙江省尚志市东北林业大学帽儿山实验林场2个10 m×10 m样地内的兴安落叶松根系进行探测,比较GPR探测结果与实地挖掘数据,分析探地雷达技术对兴安落叶松不同根径大小(0.2～0.5、0.5～1.0、1.0～2.0、2.0～3.0、3.0～4.0、4.0～5.0和>5.0 cm)和不同土壤深度(0～10、10～20和20～30 cm)根系的识别率。结果表明: 1000 MHz的GPR对根径>2.0 cm的根系识别率达到49.8%,探地雷达反射波的最大时间间隔、总时间间隔、最大振幅面积和总振幅面积与根径均呈显著正相关;对于根径<2.0 cm的根系,GPR的识别率极低,仅为6%。随着土壤深度的增加,根系识别率呈先增加后减小的趋势;在10～20 cm土层中根系识别率最大,为31.4%,在0～10 cm土层中根系识别率最小,为10.2%。探地雷达能有效识别根径(>2.0 cm)较大的兴安落叶松根系,而且对10～20 cm土层中根系具有最高的识别率,而对于小直径和深层兴安落叶松根系的探测能力仍有待提高。.
Keywords: ground penetrating radar; identification rate; root detection; root diameter; soil depth.