ESTIMATING GRAIN-YIELD OF MATURING RICE CANOPIES USING HIGH SPECTRAL RESOLUTION REFLECTANCE MEASUREMENTS
ESTIMATING GRAIN-YIELD OF MATURING RICE CANOPIES USING HIGH SPECTRAL RESOLUTION REFLECTANCE MEASUREMENTS
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DOI：
10.1016/0034-4257(91)90029-6
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发表时间：
1991-04-01
影响因子：
13.5
通讯作者：
AKIYAMA, T
中科院分区：
文献类型：
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作者：
SHIBAYAMA, M;AKIYAMA, T
水稻的籽粒产量估计从高光谱分辨率反射率（R）数据（400 - 1900 nm的间隔）约1.5个月后抽穗（约生理成熟的粮食）在三个作物季节（1985年，1986年和1987年）。 通过20 nm和40 nm宽的简单移动平均值平滑光谱数据，并计算480 nm和1680 nm之间60个中心波长的R和log（1/R）的二阶导数。 得到了这60个中心波长及其归一化差异指数组合与籽粒产量的多元线性回归方程。 每个季节的反射率的平滑和二阶导数以及归一化差异分别用于推导回归方程，以估计其余两个季节的产量。 从R的二阶导数计算的归一化差异比平滑反射率或反射率和log（1/R）的二阶导数更有效和稳定。 这一结果提供了一种方法来评估作物的谷物产量，其谷物重量在衰老过程中增加，因此受到季节后期天气和农艺条件的影响。
The grain yield of paddy rice was estimated from high spectral resolution reflectance (R) data (400 - 1900 nm interval) taken approximately 1.5 months after heading (approximately physiological maturity of the grain) during three crop seasons (1985, 1986, and 1987). Spectral data were smoothed by simple moving averages 20 nm and 40 nm wide and the second derivatives of R and log(1/R) were calculated for 60 central wavelengths between 480 nm and 1680 nm. The multiple linear regressions for these 60 central wavelengths and also for all the combinations of normalized difference indices from them versus grain yield were obtained. The smoothed and the second derivatives of reflectance and the normalized differences for each season were individually used to derive regression equations to estimate the remaining two seasons' yields. Normalized differences computed from second derivatives of R were more effective and stable for multiseasonal estimations of yield than the smoothed reflectances or the second derivatives of the reflectances and log(1/R). This result offers a method to evaluate the grain yield of crops whose grain weight increases during senescence and is therefore affected by the weather and agronomic conditions late in the season.