| 王海军,徐兴倩,屈新,赵熹,王能龙,曹涵.基于介电频谱特征参数的红壤干旱指标评价研究[J].干旱地区农业研究,2024,(1):261~269 |
| 基于介电频谱特征参数的红壤干旱指标评价研究 |
| Evaluation of red soil drought index based on dielectric spectrum characteristic parameters |
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| DOI：10.7606/j.issn.1000-7601.2024.01.27 |
| 中文关键词: 红壤 频域介电谱 特征参数 体积含水量 干旱指标 |
| 英文关键词:red soil frequency domain dielectric spectroscopy characteristic parameter volumetric water content drought index |
| 基金项目:国家自然科学基金（42367025）；云南省基础研究计划面上基金（202101AT070271）；云南省高层次人才培养支持计划“青年拔尖人才”专项（YNWR-QNBJ-2020-030）；云南省教育厅科学研究基金（2023Y1017） |
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| 中文摘要: |
| 为获取红壤含水量对电磁波介电频谱的响应特征，探讨介电频谱特征参数作为红壤干旱评价指标的可行性，以红壤为研究对象，开展不同体积含水量红壤的频域介电谱（FDS）试验，提取介电谱特征曲线积分值，分析介电频谱特征参数与体积含水量的相关性，结合国家《农业干旱等级》标准提出基于介电频谱特征参数的红壤干旱评价指标。结果表明：红壤介电常数实部和虚部均随着介电频谱频率的增大而逐渐减小，两者与体积含水量均呈正相关关系；介电损耗因数随频率变化具有波动性，且体积含水量越小波动性越强，总体呈现出先减小后增大的趋势；通过最小二乘法拟合得到介电频谱特征参数与体积含水量的量化关系，采用细菌觅食算法确定最优的模型系数，拟合精度均大于0.95；基于介电谱特征参数建立红壤干旱指标评价模型，预测值与标准值之间的误差均为±1%左右。该模型能有效地评价红壤干旱程度，可为红壤区域性农业干旱调查、评估及预警提供参考指标。 |
| 英文摘要: |
| The purpose of this study was to obtain the response characteristics of red soil moisture content to the dielectric spectrum of electromagnetic wave and discuss the feasibility of dielectric spectrum characteristic parameters as the evaluation red soil drought index. The frequency domain dielectric spectroscopy (FDS) test of red soil with different volume water content was finished, and the integral value of the dielectric spectrum characteristic curves was extracted to analyze the correlation between the dielectric spectrum characteristic parameters and the volume water content. Combined with the national agricultural drought grade standard, the red soil drought evaluation indexes based on dielectric spectrum characteristic parameters were proposed. The results showed that the real and imaginary parts of the dielectric constant of red soil gradually decrease with the increase of the frequency of the dielectric spectrum, and both were positively correlated with the volumetric water content. The dielectric loss factor fluctuates with the increasing frequencies, the smaller the volumetric water content, the stronger the fluctuation, and a trend of decreasing first and then increasing was showed. The quantitative relationship between the characteristic parameters of the dielectric spectrum and the volumetric water content was given by the least square method. The bacterial foraging algorithm was used to determine the optimal model coefficients, and the fitting accuracy was greater than 0.95. Finally, the evaluation model of red soil drought index was established based on the characteristic parameters of dielectric spectroscopy. The error between the predicted value and the standard value was between ±1%. The model could effectively evaluate the degree of red soil drought degree to provide the reference indicators for regional agricultural drought investigation, assessment, and early warning in red soil. |
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