摘要
以不同含水量的宁夏典型龟裂碱土为研究对象,系统分析了土壤光谱与土壤含水量的相关性,并建立了含水量预测模型.结果表明：随着含水量的增加,土壤光谱反射率逐渐降低,当土壤含水量高于田间持水量时,土壤光谱反射率随着含水量的增加呈增加趋势.土壤光谱反射率原始数据（r）、平滑后的反射率（R）和反射率对数（lgR）与龟裂碱土水分含量呈极显著负相关关系,整个波段R与土壤水分含量的相关系数平均比r和lgR分别高0.0013和0.0397;反射率倒数（1/R）和反射率倒数的对数[lg（1/R）]2种变换形式与龟裂碱土水分含量呈正相关关系,在950-1000 nm的相关系数平均比400-950 nm高0.2350;3种一阶微分变换形式与土壤水分的相关性不稳定.基于r、lg（1/R）、反射率的一阶微分R＇和反射率对数的一阶微分（lgR）＇采用不同回归模式建立的龟裂碱土含水量预测模型平均决定系数分别为0.7610、0.8184、0.8524和0.8255,其中R＇的幂函数模式决定系数高达0.9447,该模型预测的土壤含水量与室内实测值拟合度为0.8279,说明该模型预测精度最高,采用r建立的模型预测精度最低.研究结果可为龟裂碱土含水量预测和当地农田灌溉提供科学依据.
Based on the analysis of the spectral reflectance of the typical Takyr Solonetzs soil in Ningxia,the relationship of soil water content and spectral reflectance was determined,and a quantitative model for the prediction of soil water content was constructed. The results showed that soil spectral reflectance decreased with the increasing soil water content when it was below the water holding capacity but increased with the increasing soil water content when it was higher than the water holding capacity. Soil water content presented significantly negative correlation with original reflectance（ r）,smooth reflectance（ R）,logarithm of reflectance（ lgR）,and positive correlation with the reciprocal of R and logarithm of reciprocal [lg（ 1 / R]. The correlation coefficient of soil water content and R in the whole wavelength was 0.0013,0.0397 higher than r and lgR,respectively.Average correlation coefficient of soil water content with 1 / R and [lg（ 1 / R） ] at the wavelength of950-1000 nm was 0.2350 higher than that of 400-950 nm. The relationships of soil water content with the first derivate differential（ R＇）,the first derivate differential of logarithm（ lgR） ＇ and the first derivate differential of logarithm of reciprocal [lg（ 1 / R） ]＇ were unstable. Base on the coefficients of r,lg（ 1 / R）,R＇ and（ lgR） ＇,different regression models were established to predict soil water content,and the coefficients of determination were 0.7610,0.8184,0.8524 and 0.8255,respectively. The determination coefficient for power function model of R＇ reached 0.9447,while the fitting degree between the predicted value based on this model and on-site measured value was0.8279. The model of R＇ had the highest fitted accuracy,while that of r had the lowest one. The results could provide a scientific basis for soil water content prediction and field irrigation in the Takyr Solonetzs region.
出处
《应用生态学报》
CAS
CSCD
北大核心
2015年第3期884-890,共7页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(41001129)
宁夏回族自治区自然科学基金项目(NZ13014)资助
关键词
龟裂碱土
水分含量
光谱特征
预测
Takyr Solonetzs
water content
spectral reflectance characteristics
predict
