Abstract:Precision irrigation can improve water use efficiency and reduce environmental pollution under extensive irrigation. However, it is necessary to accurately know the pattern of soil moisture in high spatial-temporal resolution in the field, which can be measured by the active heated fiber optics (AHFO) method. However, the measuring accuracy of soil moisture under drip irrigation conditions in high spatial-temporal resolution remained unclear. The AHFO method was applied to monitor spatial-temporal variation of soil moisture under subsurface drip irrigation, which was in Shandong Province gravel area. Then, the measurement accuracy was also compared with that by TDR method. The results showed that the measured soil water content by the AHFO was well consistent with that by TDR method(P<0.01). The accuracy of AHFO method was ranging between 0.025m 3 /m 3 and 0.038m 3 /m 3 , which was slightly lower than that of other studies due to the higher gravel content. Through the real-time monitoring, soil water content showed a better response to irrigation, indicating that AHFO method can capture the evolution of soil moisture during drip irrigation. Meanwhile, soil moisture distribution was significantly correlated with gravel content(P<0.05), which dominated soil moisture in the field. The research result showed that AHFO can provide the fundamental parameter for appropriate irrigation time and amount, which was of great significance to water management in the field and the application of precise irrigation.