Using Near Infrared Technologies to Enhance Precision Management of Rice Crops- Link (January 2007)

Bowman, A Ciavarella, S Blakeney, A

2007

This RIRDC report presents the results of an evaluation of sensors which could increase the precision of variable crop fertilization. The aims of this project were to provide: an evaluation of the potential of available airborne scanning NIR sensors to determine variations in dry matter and shoot composition (eg Nitrogen and starch) across rice crops. The project also aimed to provide an understanding of the limitations of fresh tissue analysis by airborne NIR sensors calibrations for nutrients in fresh rice tissue for use in interpreting data obtained from airborne NIR sensors a basis on which to keep the Tissue Testing Service in line with the latest technology. The method used for the project included reflectance spectra from a range of rice genotypes, crop ages and densities and from common weed species were collected during the growing season using above crop scanners (hand held, airborne and satellite borne). The spectra were then used to develop calibrations for actual shoot biomass, nitrogen (N) and nitrogen uptake (N_uptake) in fresh shoots. The spectra were also used to generate a library of signals for actual shoot biomass, nitrogen and other constituents and to identify weeds and unhealthy areas in crops. An NIR specialists enabled them to effectively handle the bit-map data generated by red green blue (RGB) and infra-red camera sensors to establish if existing camera data can also be of use for crop nutrient and density prediction. The key findings were a preliminary calibrations on remotely sensed spectra of rice crops, with correlations of approximately 0.85, were established for % N and N_uptake.