Electrical capacitance estimates crop root traits best under dry conditions—a case study in cotton (Gossypium hirsutum L.)

• Published in: Plant and soil 2021-10, Vol.467 (1/2), p.549-567
• Main Authors: Gu, Huijie, Liu, Liantao, Butnor, John R., Sun, Hongyong, Zhang, Xiying, Li, Cundong, Liu, Xiuwei
• Format: Article
• Language: English
• Subjects: Agriculture; Biomedical and Life Sciences; Capacitance; Case studies; Cotton; Cutting; Cuttings; Ecology; Electric properties; Experiments; Gossypium hirsutum; Hydroponics; Life Sciences; ORIGINAL ARTICLE; Orignal Article; Physiological aspects; Plant Physiology; Plant Sciences; Plant tissues; Prediction models; Predictions; Roots; Roots (Botany); Soil conditions; Soil environment; Soil layers; Soil moisture; Soil Science & Conservation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-021-05094-6

Purpose Electrical capacitance (EC) is widely used to measure root traits especially in hydroponic and wet soil environments, but its feasibility was recently questioned due to the possible leakage of electrical current before entering the root system. To investigate whether the current can travel deeper in woody roots, EC was evaluated in cotton ( Gossypium hirsutum L . ) grown under different soil moisture conditions (two rounds of pot experiments, one PVC tube experiment and one field experiment). Methods In these experiments, electrical capacitance of the root (EC root ) was recorded before and after severing roots, and immediately afterward, the roots were collected to measure root dry weight, surface area, length, and volume. Results The results showed that EC root was significantly reduced after root cutting especially under dry conditions in the three experiments. The PVC tube experiment further demonstrated that root cutting did not significantly affect the changes in EC root measured at different soil layers under dry conditions possibly suggesting that the current could flow into the deep roots under these conditions. Moreover, incorporating root tissue density and soil moisture into the prediction model can improve the predictive accuracy of EC root . In contrast, EC root was less affected by root cutting under wet soil conditions, indicating that it may not directly measure roots under these conditions. Conclusions EC root shows the potential to directly quantify root traits under dry conditions rather than wet conditions.