Study On Growth Information Of Tall Fescue Under Different Growth Environment Based On Hyperspectral Remote Sensing Data

As the intensifying of greenhouse effect and water shortages, the lawn grass growth period of dynamic monitoring, the precise fertilization management measures and reasonable irrigation has more and more important significance in practical application. Monitoring the growing of plants by analysis the indicators which represent plant growing could provided a theoretical basis for monitoring the growth of tall fescue using hyperspectral remote sensing technology and reasonable irrigation.The tall fescue plants (Festuca arundinacea Schreb.) were taken as experiment material. They were planted in pots in the incubator greenhouse and the CO2concentration as well as the atmospheric humidity was artificially controlled, which putted on orthogonal test. We measured the spectral reflection index of the leaves by spectrometer and SPAD (Soil Plant Analysis Development) value in the heading stage. Li-6400portable photosynthesis system was used to determinate the photosynthetic physiological parameters of tall fescue under different CO2and soil moisture treatments. The Parameters include net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular carbon dioxide concentration (Ci) and transpiration rate (Tr) and so on. Then the water use efficiency (WUE) is calculated under different growing conditions. The relationship between SPAD value and spectral data are analyzed using multivariate statistical methods such as correlations and regressions. The changes of photosynthetic physiological parameters are analyzed the variation too. We analyzed the relationship between the red edge parameters, vegetation index and derivative spectra which extracted from spectral data and SPAD value respectively. The results showed that:(1)The spectral characteristics of tall fescue leaves had close correlation to pigment contents of leaves and the structure of mesophyll cells, but were independent to growth environment.(2)Three spectral indices of the red edge position, NDVI and the average derivative spectral data of695-715nm, had a favorable correlation with SPAD value. SPAD value could be good inverted by red edge position, NDVI and derivative spectra. The edge position most accurately estimated SPAD value of tall fescue leaf, next was NDVI index, least is the derivative spectra index.(3)The photosynthetic production capacity of the tall fescue decreases marginally when soil moisture decrease, which illustrate the drought with a strong production capacity. (4) The variation of CO2concentration has the greater influence on the physiological status of tall fescue than the variation of soil moisture.(5) Tall fescue isn’t sensitive to water use efficiency when soil moisture is at40%-85%FC. Thus, in order to economize on water and improve the efficiency of plant photosynthesis, it is necessary to control soil moisture at the lower limit of40%FC in the conditional area and widely grow tall fescue which is drought-resistant plants in the arid and water shortage area.