The spatial identification of nitrogen concentrations in winter wheat using Hyperspectral Sensor Data
Site-specific, Chlorophyll, Red-Edge, Hyperspectral Imaging, Leaf Reflectance
Description - Increasing Groundwater Nitrate Concentration have led to the need for improved N (side-specific) fertilizer management, especially in huge production areas. Nitrogen is on the one hand the most limiting nutrient for crops, on the other hand easy displaceable within the soil layers. An equal adjusted N-Distribution could let to an optimal qualitative and quantitative yield. Non-destructive and contactless reflectance detection relieves the implementation of a site-specific N-Management. In this connection Hyperspectral Imaging data provides a significant enhancement of spectral measurement capabilities over conventional remote sensor systems and can also provide improvements in the generated spectral information. The nutrient nitrogen itself shows a highly significant correlation with the pigment chlorophyll. Thereby Chlorophyll influences primarily the Leaf reflectance in the 400- to 750-nm wavelength interval. At the transition from red to NIR wavelengths, leaf reflectance greatly increases, producing a distinct spectral feature referred to as the red edge. The positioning of this edge has been correlated mainly to chlorophyll content as well as plant phenological stages and plant stress. In 2007 a winter wheat (Triticum aestivum L.) field trial on a Agricultural Research Station of the University Bonn was established. Within the field 10 test sites (8x8m) where located to represent the heterogeneity in the field. The objective of this project is to evaluate if differences in the spectral signatures (taken of the 10 test sites) can be related to ground truth data collected during the growth stage and can be used to optimize site-specific N-Applications.
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