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| DOI：10.13522/j.cnki.ggps.2020639 |
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| Optimal Spectral Eigenvalues to Estimate Nitrogen Content in Potato Leaves |
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HAN Kang, YU Jing, LI Rui, FAN Mingshou
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1.Inner Mongolia Agricultural University, Hohhot 010019, China;2. Ordos Soil and Fertilizer and Water-saving Agriculture Work Station, Erdos 017010, China
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| Abstract: |
| 【Background】Hyperspectral reflectance information from crop canopy can be used to estimate crop healthy, and the spectral eigenvalues extracted from it have been used to successfully diagnose plant nitrogen content. This can help fertilization thereby improving nitrogen use efficiency and reducing its detrimental impact on the environment. The sensitivity of the spectral eigenvalues to plant nitrogen content varied between crops and their cultivars. Currently, it remains elusive if the sensitive spectral eigenvalue obtained from one crop applies to other crops.【Objective】The aim of this paper is to study the quantitative relationship between different spectral eigenvalues extracted from hyperspectral imageries and the nitrogen content in leaves of potatoes watered by drip irrigation. 【Method】The experiments were conducted in a field grown with various potato varieties, all fertilized with a nitrogen gradient ranging from 0 to 600 kg/hm2. The relationship between nutrient content in the leaves of all varieties at different growth stages and different spectral eigenvalues was analyzed using regression models.【Result】The ratio of the red edge area to the blue edge area, RI, and the nitrogen accumulation in the leaves (LNA) were most closely correlated at all growth stages. The relationship between RI and LNA was quadratic in less than 65 days after the seedling emergence, while for the whole growing season, an exponential model was more accurate. The regression model was accurate and reliable to predict leaf nitrogen content in less than 35 days after the seedling emergence and for the whole growing season, regardless of the nitrogen fertilization and changes in the environment and crop varieties, with R2>0.7 and RMSE ranging in 4.348~8.844, 6.665~17.725 and 8.862~17.725 kg/hm2, depending on growth stages and crop varieties.【Conclusion】RI can be used as the spectral eigenvalue to estimate nitrogen content in potato leaves at different growth stages. |
| Key words: potato; leaf nitrogen content; spectral eigenvalue; predicting model |
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