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Detection of nitrogen deficiency in wheat from spectral reflectance indices and basic crop eco-physiological concepts

Rodriguez, D. and Fitzgerald, G.J. and Belford, R. and Christensen, L.K. (2006) Detection of nitrogen deficiency in wheat from spectral reflectance indices and basic crop eco-physiological concepts. Australian Journal of Agricultural Research, 57 (7). pp. 781-789.

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Article Link(s): http://dx.doi.org/10.1071/AR05361

Publisher URL: http://www.publish.csiro.au

Abstract

We tested the capacity of several published multispectral indices to estimate the nitrogen nutrition of wheat canopies grown under different levels of water supply and plant density and derived a simple canopy reflectance index that is greatly independent of those factors. Planar domain geometry was used to account for mixed signals from the canopy and soil when the ground cover was low. A nitrogen stress index was developed, which adjusts shoot %N for plant biomass and area, thereby accounting for environmental conditions that affect growth, such as crop water status. The canopy chlorophyll content index (CCCi) and the modified spectral ratio planar index (mSRPi) could explain 68 and 69% of the observed variability in the nitrogen nutrition of the crop as early as Zadoks 33, irrespective of water status or ground cover. The CCCi was derived from the combination of 3 wavebands 670, 720 and 790 nm, and the mSRPi from 445, 705 and 750 nm, together with broader bands in the NIR and RED. The potential for their spatial application over large fields/paddocks is discussed.

Item Type:Article
Corporate Creators:Department of Employment, Economic Development and Innovation (DEEDI), Agri-Science, Crop and Food Science, Plant Science
Business groups:Agri-Science, Crop and Food Science
Additional Information:Reproduced with permission from © CSIRO Publishing. Access to published version may be available via Publisher’s website.
Keywords:Nitrogen stress index; plant density; remote sensing; water stress.
Subjects:Agriculture > Agriculture (General) > Special aspects of agriculture as a whole > Remote sensing
Plant culture > Field crops > Wheat
Agriculture > Agriculture (General) > Fertilisers
Deposited On:02 Feb 2009 01:45
Last Modified:26 Oct 2011 00:24

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