宇宙射线快中子法在土壤水分测量中的应用——以陕北六道沟流域为例  

Application of cosmic-ray fast neutron method to measure soil moisture:A case study of Liudaogou basin in Shaanxi

作　　者：王秋铭[1] 王胜 樊军[1,2] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨陵712100

出　　处：《中国水土保持科学》2015年第5期125-131,共7页Science of Soil and Water Conservation

基　　金：国家自然科学基金重点项目"黄土坡地土壤养分随地表径流流失动力机制与模拟模型"(51239009);国家自然科学基金"水蚀风蚀交错带不同植物利用水源的差异与共存机制"(41271239);中国科学院西部行动计划项目"晋陕蒙能源基地受损生态系统恢复重建关键技术与示范"(KZCX2-XB3-13)

摘　　要：利用宇宙射线快中子法能够测量半径300 m左右源区内的土壤水分含量,其较大的测量源区填补了传统点观测和遥感大面积观测尺度之间的空白。本文通过对比分析COSMOS土壤含水量与TDT土壤含水量,以验证宇宙射线土壤水分观测系统的可靠性,以期为黄土高原水蚀风蚀交错区的中尺度土壤水分测量提供依据。本试验利用国产宇宙射线土壤水分观测系统（COSMOS）于2014年5月21日至10月31日对位于陕北神木县六道沟流域的坡地土壤水分进行自动监测,并用测量区典型点取样法对其校正。同时在源区内的试验小区埋设TDT探头测量土壤含水量。结果表明：COSMOS土壤水分主要受源区内降水的影响,对每次降水不仅能做出灵敏反应,且反应剧烈程度明显受降水量的影响。COSMOS观测数据很好地反映了源区内坡地径流小区土壤水分的变化趋势。与3种土地利用方式、2个深度的TDT探头所测得土壤含水量的平均值呈显著的线性相关关系,R2=0.76,均方根误差为0.022 cm3/cm3。COSMOS土壤含水量与0-10 cm土层含水量的相关系数均大于10-20 cm土层,从本试验的数据来看,COSMOS对于浅层（0-10 cm）土壤平均含水量适用性较好。TDT探头所测得的坡耕地土壤平均含水量与COSMOS测得的土壤平均含水量的相关性略差于苜蓿地和撂荒地。本研究证实了宇宙射线土壤水分观测系统能够为坡面尺度土壤水分和径流预测模型提供数据。As an important component of water resources,soil moisture plays a crucial role in the energy exchange between soil and atmosphere,and is also an important part of every ecosystem. The soil moisture has a significant effect on the soil erosion process; therefore,it is very momentous to obtain the soil moisture content accurately and continuously. As we all know it is very difficult to measure regionscale soil moisture but now soil moisture at a horizontal scale of around 300 m can be observed by the cosmic-ray fast neutron probe,which makes this method available to fill the gap between small scale oftraditional point measurement and large scale of remote sensing measurement. We compared soil moistures form COSMOS and TDT to verify the accuracy of COSMOS and provide a method to measure the soil moisture in wind-water erosion crisscross region. In this study,the domestic cosmic-ray soil moisture observing system（ COSMOS） was used to observe soil moisture of slope field in Liudaogou basin of Shaanxi Province during the period of 21 May 2014 to 31 October 2014. TDT probes were set in 5 cm and15 cm deep in the soil of all plots. Main results are presented as follows. COSMOS soil moisture was mainly affected by precipitation and could reflect sensitivity on the precipitation. The results of the COSMOS soil moisture well reflected the variation trend of soil moisture at the field scale,and had a linear correlation with the average of the results measured by TDTs in two depths of three experimental plots. The R2 was 0. 76 and the root mean square error was 0. 022 cm3/ cm3. We found the correlation coefficient of COSMOS soil moisture and TDT soil moisture in 0-10 cm were greater than those in 0-20 cm from the comparison between the results measured by TDT in two depths of all experimental plots and COSMOS. Based on this,we can consider that the average soil moisture measured by COSMOS was more consistent with the water content of the soil near the surface. And we found the correlation coefficient of COSMOS soil moistu

关 键 词：土壤含水量 农田尺度 COSMOS 陕北六道沟流域 

分 类 号：S152.7[农业科学—土壤学]