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通过田间小区试验,测定了4个春小麦品种(定西24号、陇春8139、高原602和定西38号)在不同生育期和不同种植密度下冠层光谱反射率及其对应的地上鲜生物量,分析了春小麦地上鲜生物量随生育期的变化以及地上鲜生物量与冠层反射光谱和一阶微分光谱之间的相关关系,采用相关系数较大的特征波段及其组合构建光谱特征参数以其作为变量,建立了春小麦地上生物量的高光谱估算模型,并对模型进行检验。结果表明:以参数F780和D719为变量的对数形式y=3.9498ln F780+7.0596和乘幂形式y=512.99D7191.0174估算水平最高,前者均方根误差(RMSE)为0.2173,相对误差(RE)为10.45%,预测值与实测值相关系数为0.854;后者RMSE为0.2188,RE为9.96%,预测值与实测值相关系数为0.853。因此,上述两个模型可作为陇中黄土高原地区春小麦地上鲜生物量的最佳估算模型。
Through field plot test, the canopy spectral reflectance and corresponding aboveground fresh biomass of four spring wheat cultivars (Dingxi 24, Longchun 8139, plateau 602 and Dingxi 38) were measured at different growth stages and different planting densities. The relationship between the fresh biomass of spring wheat and the canopy reflectance spectra and first order differential spectra was analyzed. The spectral bands and their combinations were used to construct the spectral characteristic parameters As a variable, the hyperspectral estimation model of spring wheat aboveground biomass was established, and the model was tested. The results showed that the logarithmic form y = 3.9498ln F780 + 7.0596 and the exponentiation form y = 512.99D7191.0174 with the parameters F780 and D719 as the variables had the highest level of estimation. The RMSE was 0.2173 and the relative error (RE ) Was 10.45%. The correlation coefficient between predicted and measured values was 0.854. The latter had RMSE of 0.2188 and RE of 9.96%. The correlation coefficient between predicted and measured values was 0.853. Therefore, the above two models can be used as the best estimation model of aboveground fresh biomass of spring wheat in Longzhong Loess Plateau.