EVALUATION OF WHEAT GROWTH MONITORING METHODS BASED ON HYPERSPECTRAL DATA OF LATER GRAIN FILLING AND HEADING STAGES IN WESTERN AUSTRALIA
This study estimated the wheat yield, quality, and growth conditions using hyperspectral data of the later grain filling and heading stages. The study area is located in the suburbs of Mullewa, Western Australia. Various data used included spectral reflectance of wheat measured from the ground and those measured using airborne sensors, wheat growth conditions data, such as LAI, SPAD values, and wheat height, and sample analysis data, including biomass, grain nitrogen content rate, leaf nitrogen content rate, and ash content, of the later grain filling and heading stages. This study consisted of (1) selection of estimation items regarding the wheat yield, quality, and growth conditions by correlation analysis of sample data, (2) definition of estimate equations for selected items, (3) verification of estimation accuracy, and (4) development of estimation maps. As a result, head moisture, which is related to the wheat growth conditions, was well estimated using hyperspectral data of the later grain filling stage. At the same time, grain weight, which is related to the wheat yield, and grain nitrogen content rate and ash content, which are related to the wheat quality, were well estimated using hyperspectral data of the heading stage. This study implies that it is possible to visualize the wheat yield, quality, and growth conditions on a regional scale using hyperspectral data.