Spectral Indices Based Monitoring Of Potato Growth In Greenhouse

Timely and accurate monitoring of aboveground biomass, plant N uptake and chlorophyll content at gifferent growth stages of crop play a crutial role in effectively managing N fertilizer and reducing environmental pollution. In order to timely detect the growth of potato plants and estimate N status, an experiment was conducted in the grennhouse to eshtalish the relationship between optimized spectral indices and agronomic parametwers based on ratio, normalized algorithm and concenptual model algorithm. The main conclusion was as follows:（1） Growth stages have a great influencence on sensitive bands of aboveground biomass, plant N uptake and SPAD value of potato. These sensitive bands varied with the variation of growth stages. With the identification of sensitive bands of aboveground biomass, plant N uptake and SPAD value, the results indicate that the almost similar sensitive bands were observed in aboveground biomass and plant N uptake, and have a difference with SPAD value.（2） Compared with the pubplished spectral indices, bands optimum algorithm significantly improved the predictive ability of spectral indices in estimating aboveground biomass. plant N uptake and SPAD value of potato. The optimized bands combinations of spectral indices are mainly focus on the area of red edge and near infrared, which overcome the saturation problem of red light based spectral indices under high biomass conditions.（3） Combining all data of different growth stages of potato, the best performing spectral indices of conceptual model algorithm were R.800/R732-1、R.800/R732-1 and R.800/R728-1。For ratio algorithm, the best performing indices were R941/R740、R942/R₇₂₀ and R774/R732 respectively。For normalized difference algorithm, the best indices were （R942-R722）/（R942+R722）、CR942-R722)/（R942+R722） and （R774-R732）/（R774+R732）。...