Canopy reflectance thermal stress and apparent s

Authors: CarlGöran Pettersson Mats Söderström Henrik Eckersten

Publish Date: 2006/08/18

Volume: 7, Issue: 5, Pages: 343-359

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Abstract

Three consecutive crops of malting barley grown during 2002–2004 on clayloam on a Swedish farm 59°74’ N 17°00’ E were monitored for canopy reflectance at growth stages GS32 second node detectable and GS69 anthesis complete and the crops were sampled for above ground dry matter and nitrogen content GPSpositioned unfertilised plots were established and used for soil sampling At harvest plots of 025 m2 were cut in both fertilised and unfertilised plots and 24 m2 areas were also harvested from fertilised barley The correlations between nine different vegetation indices VIs from each growth stage and yield and grain protein were tested All indices were significantly correlated at 5 level with grain yield GY and protein when sampled at GS69 but only four when sampled at GS32 Three variables the bestcorrelated vegetation index sampled at GS32 an index for accumulated elevated daily maximum temperatures for the grain filling period and normalised apparent electrical conductivity ECa of the soil were sufficient input in the final regressions Using these three variables it was possible to make either one multivariate PLS regression model or two linear multiple regression models for grain yield GY and grain protein with correlation coefficients of 090 and 073 for yield and protein respectivelyWe wish to thank Kristina Eek and Anders Anderson Yara Sweden and the Yara NSensor team in Hanninghof Germany for their help and support in extracting data from obscure log files Thanks to Professor Robert Hay who has helped us put this material into a bigger context and also helped a lot with our use of English

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