Remote Sensing Quantitative Inversion Of The Chlorophyll Of Paddy And Research On The Correlation Between Chlorophyll And Soil Heavy-metal

The farmland in industrial area has been suffering from the heavy-metal pollution for a long time. As people's awareness rises up, poisonous rice, cadmium in rice and other food security is being taken into closer attention. The farmland heavy-metal pollution threatens people health, so it is urgent to take measures to monitor and control the pollution.Chlorophyll content is an important indicator of plant photosynthesis, growth status and environmental stress, monitoring the change of chlorophyll in heavy-metal stress, can determine the degree of heavy-metal stress, this can be a way to monitor the farmland heavy-metal pollution. At first, this article analyzed the sensitivities of chlorophyll content, the carotenoids content, the leaf area index(LAI), leaf inclination angle distribution(LAD), content of material, equivalent water content, the result showed the sensitivity of both the LAI and the chlorophyll were stronger than the others. Second, based on the sensitivity analysis, model PROSAIL was used to construct the LAI-chlorophyll lookup table, using the correlation between the treated remote sensing image and the LAI-chlorophyll lookup table, the chlorophyll content was inversed with a good result, this result is coincide to the real and the correlation index is 0.69.Considering the biochemical mechanism relation between heavy-metal and the chlorophyll, the correlation between measured rice leaf chlorophyll and laboratory content results of Zn, Cu, Cd and As were analyzed and that this four heavy-metal elements has a strong negative correlation with the rice chlorophyll was found. Using the correlation and using the soil heavy-metal content corresponded to chlorophyll content, the remote sensing inversion result of rice chlorophyll was graded. Based on the grade result, the soil heavy-metal stress was graded; at the same time, measured chlorophyll content was graded. The grade based on remote sensing inversion and the grade based on measured data was found to have the consistency.Because physical model paddy chlorophyll inversion can be quantitative and accurate, there is a clear correlation between paddy chlorophyll and soil heavy-metal, the result of heavy-metal level evaluation is identical to the real, this can be a good way to monitor the heavy-metal pollution in farmland soil.