摘要
雷达信号是反映介质信息的重要依据,为探究雷达信号对长期膜下滴灌棉田土壤水盐的响应特征。试验采用中心频率为250 MHz的pulse EKKO PRO探地雷达,以未采用过滴灌技术的荒地为对照,探测滴灌应用年限年分别为11年和21年的两个地块,取实测剖面对比探地雷达波谱图像上的分层结果,结合电磁波时域和频域的方法,剖析电磁波信号对土壤水盐的响应特征。结果表明:①通过250 MHz中心频率探地雷达波谱图像上的反射层面与实际开挖剖面相结合,能够快速识别膜下滴灌棉田0~140 cm范围不同土层的上下边界。同时,结合取样数据时,能够有效的辨别大范围的土层结构信息。但当水盐含量较高时,探地雷达将无法有效识别土壤的反射层面,从而很难分辨土壤的层次结构。②长期膜下滴灌棉田盐渍化土壤对电磁波的影响十分显著,水分含量和盐分含量是引起电磁波衰减的主要因素。振幅能值是雷达信号对水盐响应的标志参数,水盐含量与振幅能值成反比。③中心频率为250 MHz的天线在不同滴灌年限的地块中,主频发生偏移,滴灌棉田出现在160 GHz左右,而荒地出现在190GHz左右。荒地中出现多峰现象,次主频分别处于371 MHz和688 MHz。且荒地的振幅能值小于滴灌棉田。利用探地雷达快速无损的优势,大面积获取膜下滴灌棉田土壤水盐的变化信息,有利于盐碱化土壤的及时处理。
The radar signal is an important basis for reflecting the information of the medium.In order to explore the response characteristics of the radar signal to the water and salt in the cotton field soil under long-term drip irrigation,in this experiment,the pulse EKKO PRO ground penetrating radar with a center frequency of 250 MHz was adopted with the wasteland without drip irrigation as a control,the two plots with a drip irrigation period of 11 years and 21 years were detected.The measured profile was compared with the stratified results of GPR spectral images,and the response characteristics of electromagnetic wave signals to soil water and salt were analyzed by combining the methods of electromagnetic wave time domain and frequency domain.The results show that:①The combination of the reflection layer on the GPR image and the actual excavation profile can quickly identify the upper and lower boundaries of different soil layers in the 0~140 cm range of drip irrigation cotton fields under the film.At the same time,when combined with sampled data,it can effectively identify a wide range of soil structure information.However,when the water and salt content is high,GPR will not be able to effectively identify the reflective layer of the soil,making it difficult to distinguish the soil hierarchy.②The long-term drip irrigation of saline soil in the cotton field under film has a significant effect on electromagnetic waves.Moisture content and salt content are the main factors that cause electromagnetic wave attenuation.The amplitude energy value is a sign parameter of the radar signal response to water and salt,and the water salt content is inversely proportional to the amplitude energy value.③For antennas with a center frequency of 250 MHz,the main frequency shifted in plots with different drip irrigation years.The drip irrigation cotton field appeared around 160 GHz,and the wasteland appeared around 190 GHz.The multi-peak phenomenon occurs in the wasteland,with the sub-primary frequencies at 371 MHz and 688 MHz,respectively.And the amplitude energy value of the wasteland is less than that of drip irrigation cotton field.Using the advantages of rapid and non-destructive ground penetrating radar,large-area acquisition of soil water and salt change information of drip irrigation in cotton fields under a large area is conducive to the timely treatment of saline-alkali soils.
作者
邹杰
张金珠
王振华
宗睿
温越
陈潇洁
ZOU Jie;ZHANG Jin-zhu;WANG Zhen-hua;ZONG Rui;WEN Yue;CHEN Xiao-jie(School of Water Conservancy and Civil Engineering,Shihezi University,Shihezi 832000,Xinjiang,China;Key Laboratory of Modern Water-saving Irrigation,Xinjiang Production and Construction Corps,Shihezi 832000,Xinjiang,China)
出处
《节水灌溉》
北大核心
2021年第5期28-35,共8页
Water Saving Irrigation
基金
国家自然科学基金项目(51869027)。
关键词
雷达信号
探地雷达
长期膜下滴灌
土壤剖面
土壤水盐
radar signal
GPR
long-term drip irrigation under film
soil profile
soil water and salt
