张智韬, 杜瑞麒, 杨帅, 杨宁, 魏广飞, 姚志华, 邱元霖. 水盐交互作用对河套灌区土壤光谱特征的影响[J]. 农业工程学报, 2020, 36(18): 153-164. DOI: 10.11975/j.issn.1002-6819.2020.18.019
    引用本文: 张智韬, 杜瑞麒, 杨帅, 杨宁, 魏广飞, 姚志华, 邱元霖. 水盐交互作用对河套灌区土壤光谱特征的影响[J]. 农业工程学报, 2020, 36(18): 153-164. DOI: 10.11975/j.issn.1002-6819.2020.18.019
    Zhang Zhitao, Du Ruiqi, Yang Shuai, Yang Ning, Wei Guangfei, Yao Zhihua, Qiu Yuanlin. Effects of water-salt interaction on soil spectral characteristics in Hetao Irrigation Areas of Inner Mongolia, China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2020, 36(18): 153-164. DOI: 10.11975/j.issn.1002-6819.2020.18.019
    Citation: Zhang Zhitao, Du Ruiqi, Yang Shuai, Yang Ning, Wei Guangfei, Yao Zhihua, Qiu Yuanlin. Effects of water-salt interaction on soil spectral characteristics in Hetao Irrigation Areas of Inner Mongolia, China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2020, 36(18): 153-164. DOI: 10.11975/j.issn.1002-6819.2020.18.019

    水盐交互作用对河套灌区土壤光谱特征的影响

    Effects of water-salt interaction on soil spectral characteristics in Hetao Irrigation Areas of Inner Mongolia, China

    • 摘要: 为探究土壤水盐交互作用对Sentinel-2卫星光谱特征的影响,该研究以内蒙古河套灌区沙壕渠灌域为研究区域,分别在2018年和2019年的4-5月共采集280个裸土期表层土壤样本,测定其土壤含水率和含盐量,并获取同步的Sentinel-2卫星遥感数据,构建基于土壤水盐-反射率原理的土壤光谱特征理论模型,在此基础上结合土壤水盐交互作用构建水盐交互模型,并比较2种模型对土壤光谱的模拟效果,分析土壤水盐交互作用对土壤光谱估算的影响。结果表明:1)土壤水盐交互作用对光谱的影响因波段类型和水盐含量的不同而有所不同。在可见光范围上影响相对较弱,其作用范围为-0.11~0.29;在近红外和短波红外范围上影响相对较强,其作用范围为-0.35~0.61;当水分或盐分中某个含量较高时对光谱影响较弱,在水盐含量程度相似时影响较强。2)与土壤光谱特征理论模型相比,水盐交互模型能明显地改善土壤光谱的模拟效果,能将模拟相关系数由0.14~0.44提升到0.29~0.59,均方根误差由0.032~0.082降低到0.029~0.068。该研究结果揭示了盐分和水分对光谱特征的干扰过程,为土壤盐分的估算提供策略与方法,对实现区域尺度上土壤盐分的精准监测具有一定的意义。

       

      Abstract: Abstract: Hetao irrigation area is characterized by less precipitation and more evaporation, which makes the sever soil salinization. Satellite based on remote sensing technology can quickly and accurately monitor the dynamic changes of soil salinization, and provide effective information and methods for land management and ecological restoration. Soil moisture and salinity have similar effects on soil spectrum. In order to explore the influence of soil water-salt interaction on the spectral characteristics of Sentinel-2 satellite, a total of 280 surface soil samples were collected from April to May in 2018 and 2019 in Shahao canal irrigation area of Hetao Irrigation Area in Inner Mongolia, China. Soil moisture content and electrical conductivity were measured, and Sentinel-2 satellite remote sensing data were obtained to construct the soil water-salt-reflectance model based on theory of soil spectral characteristics. Combined with soil water-salt interaction, the water-salt interaction model was constructed, and the simulation effects of the two models on soil spectrum were compared, and the influence of soil water-salt interaction on soil spectral estimation was analyzed. The results showed that: 1) the water-salt interaction was affected by soil moisture and salinity. In the visible light range, the effect range was from -0.11 to 0.29. In the near infrared and short wave infrared ranges, the effect was relatively strong with the range from -0.35 to 0.61. When the soil moisture or electrical conductivity were high, the influence was weak. When the soil moisture or electrical conductivity was similar, the effect was strong. 2) Compared with the theoretical model of soil spectral characteristics, the water-salt interaction model significantly improved the simulation accuracy of soil spectrum, increased the simulation correlation coefficient from 0.14-0.44 to 0.29-0.59, and reduced the root mean square error from 0.032-0.082 to 0.029-0.068. At the same time, compared with the theoretical model, the range of relative error of soil water-salt interaction model was smaller, and the area occupied by low error was larger, indicating that the relative error distribution estimated by reference spectrum can provide valuable information for the retrieval of soil moisture or salt content by Sentinal-2 satellite, and the inversion can be further improved by considering water- salt interaction. 3) The characteristic quantities based on the brine ratio could reflect the water-salt interaction of soil, but the correlation between them changed with the change of brine ratio. When the brine ratio was greater than 1, the correlation between water-salt interaction and characteristic quantity was mainly 0.26-0.49; when the brine ratio was less than 1, the correlation between water-salt interaction and characteristic quantity was mainly 0.35-0.54. This study reveals the interference process of salt and water on spectral characteristics, provides strategies and methods for soil salt estimation, and has certain significance for realizing accurate monitoring of soil salinity at regional scale. However, vegetation coverage is not involved in the study. Therefore, it is necessary to study the spectral characteristics of water-salt interaction from vegetation growth and development and water-salt response mechanism in the future.

       

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