滴灌下AHFO法监测砾石区土壤水分时空变异研究
Spatial-temporal Variation of Soil Moisture Monitored Using AHFO under Drip Irrigation in Gravel Area
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摘要: 为监测滴灌条件下的田间土壤水分变化,利用主动加热光纤(Active heated fiber optics,AHFO)法监测山东省砾石区地下滴灌下的土壤水分时空变异,并用时域反射技术(Time domain reflectometry,TDR)法对比其测量精度。结果表明,AHFO法与TDR法测得的土壤含水率具有较好的相关关系(P <0.01),AHFO法测量精度在0.025~0.038 m3/m3之间;由于砾石的影响,AHFO法的测量精度略有降低;采用AHFO法测得的土壤含水率对灌溉有较好的响应,说明AHFO法能够获取滴灌过程土壤水分的演变;采用AHFO法测得的土壤含水率空间分布与砾石含量具有显著相关关系(P <0.05),说明砾石含量是控制田间土壤水分的主导因素。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. 025 m~3/m~3 and 0. 038 m~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.