The map for grain protein content of winter wheat using satellite observed NDVI at maturing stage

Abstract

In order to make the map of grain protein content of winter wheat in large area, we investigated the relationship between grain protein content and spectral response of visible and near infrared bands of satellite data. SPOT, QuickBird and Terra/ASTER satellites data were used, and they were mainly observed from June to July in the year from 2002 to 2004, selecting 4 study areas in central and eastern part of Hokkaido. Target wheat variety was "Hokushin". The results showed that we could estimate the grain protein content using the normalized deference vegetation index (NDVI) with more than 0.6 of the coefficient of determination (R²) between three weeks before maturing stage and the stage. This observation period almost corresponds to the period from late June to mid-July in Hokkaido and we evaluated the possibility to get satellite data using Terra/MODIS and Aqua/MODIS satellites data for study area. As the results, we would have enough chance to get clear satellite data in this period using the SPOT sensors that has pointing ability. The distribution map of the grain protein content can be obtained by applying the regression formula between NDVI and the protein content to each pixel of wheat field extracted from the satellite data, and makes clear the fluctuation of protein content not only in an area level but also in a field level. In addition, this map can provide effective information for crop management such as nitrogen fertilizer rate in successive years.