Monitoring Photosynthetic Status And Growth Paramenters In Rape With Canopy Spectral Reflectance

Along with the development of precision agriculture, spectral digital technology has become an important research method of digital agriculture. Green plants have typical spectral characteristics, and in crop growth process, different water management and cultivation measures and cultivar type lead to change crop growth condition, which can form unique spectral features. This article mainly expounded the agricultural spectrum significance of digital technology, introduced the principle of agricultural spectroscopy technology and the spectral characteristics in plant, analyzed the current situation of the study of agricultural spectroscopy and the existing problems, and introduced the spectrum technology of the application in the crop science and technology, including crops photosynthetic, growth, water content, n nutrition, yield and quality to monitor.Net photosynthetic rate is the important index which can measure the amount of photosynthesis, and non-destructive and fast monitoring crop net photosynthetic rate have the important meaning to guide the field real-time management and productivity prediction. With1613rapeseed varieties in different leels of fertilizer and dense field test as the foundation, the quantitative relation between rape leaf and silique photosynthetic rate and canopy spectral reflectance was study systematacially. The results showed:RSI (R760.R766) has a significant linear relation to the rape leaf photosynthetic rate, and NDSI (R951.R948) has a significant linear relation to the rape silique photosynthetic rate. Using different years of rape trials rape leaf and silique photosynthetic rate monitoring models were tested, with the test model error RMSE0.747and0.349, respectively. This shows that RSI (R760.R766) and NDSI (R951,R948) respectively is better able to monitor rape leaf and silique photosynthetic rate under different fertilizer and dense condition.Crop chlorophyll condition is an important index in photosynthetic efficiency evaluation, health condition monitoring and nitrogen management, and there is great significance to nondestructive monitor chlorophyll condition in crop diagnosis growth, yield prediction and nitrogen management. This paper with different nitrogen and planting density level of field experiment as the foundation, analyzed the quantitative relations between the rape chlorophyll content and canopy spectral reflectance, and put forward the rape of chlorophyll status monitoring model, and compared the prediction precision of these monitoring system. The results showed that, the normalized spectra indexes NDSI (R2207,R618) formed by rape canopy spectral reflectance has a significant linear and index relation to the chlorophyll content p. and established monitoring models also have more high fitting precision through inspection.With sdudying the period change character of rapeseed canopy spectral under different fertilizer and dense condition, the quantitative relation between the canopy spectral reflectance and leaf area index was constructed.The results showed that rape leaf area index of sensitive band scope mainly in680-1110and450-nm750nm area, and in the the area the exponential function of monitoring model established by NDSI (R722.R721) which is formed by722nm and721nm bands has a higher prediction accuracy, and inspection achieves significant fitting level, with the highest R2for0.5207. and a smaller RRMSE for0.731.Dry weight is an important parameters to describe the crop growing, and dynamic monitoring dry weight takes an important role in rapeseed growth monitoring and management regulation.For sure accuracy of a variety of spectral index forecasting rape plant dry weight, as to establish a reliable quantitative monitoring model for plant dry weight, in two consecutive years field experiments processed in different nitrogen and planting density level.this research collected the canopy spectral reflectance and dry weight data in different growth stages of the rape. The results showed that, sensitive band combination for plant dry weight and canopy spectral reflectance is1036and1035nm n,1200nm and1158nm. The monitoring models formed by the former have R2to be0.57. SE to be9.6.and by the latter R2to be0.62. SE to be10.044. In different experimental conditions, dry weight can be inverted quantitatively by the united spectrum parameters, in which the equation of spectral parameters based on NDSI (R1200,R1158) and RSI (R1200,R1158) have good fitting effect.Crops nitrogen condition is an important index in knowing well growth, increasing yield and improving quality, and there is great significance to monitor plant nitrogen content in crop diagnosis growth, yield prediction and nitrogen management. The purpose of this paper was to comprehensively analysis the relationship between the rape leaf nitrogen content and canopy spectral and parameters, and compare effect of spectral parameters for estimating plant nitrogen content, as to establish quantitative monitoring of rape plant nitrogen model. With different nitrogen and planting density level of different growth stages rape field experiment data as the foundation,this research makd full use of the nondestructive timely monitoring characteristics of the remote sensing spectrum technology, utilized the normalized and ratio spectra indexes and plant nitrogen content to go to relevant analysis systematacially, and compared and analysised the simulation effect and the model prediction ability of different forms of spectrum parameters in monitoring plant nitrogen content. The results showed that the index function monitoring model established by NDSI (R816.R760) and the power function monitoring model established by RSI (R791.R760) can simulate plant nitrogen content well, and the results of model tests also showed that between the predicted values and the measured values for the two models, there is an significant fitting level.Concrete applications of the spectrum monitoring technology in monitoring rape photosynthesis and growth under different fertilizer and planting density level were comprehensively analysised and discussed. These specific application includes monitoring rape net photosynthetic rate, monitoring the leaf chlorophyll content, monitoring leaf area index, monitoring plant nitrogen content, monitoring plant dry weight, and the future research ideas have been clear. Finally the main results of the study have been summarized.