The Influence Of N Treatment On Hydroponic Brassica And Lettuce’s Growth、Leaf Photosynthetic And Fluorescence

In order to use hyperspectral detection techniques to diagnosis without damage, adjusting the nitrogen concentration on the basis 1/2 dose of Japanese Garden Formula, and discuss the relationship between nitrogen of Brassica and Lettuce, chlorophyll and spectral reflectance under different nitrogen concentrations. As a result, we could not only get the spectrum function of the combination between best spectrum and Brassica and Lettuce’s growth, but also the most sensitive wavelength range. In this situation, building the model of nitrogen、chlorophyll in Brassica and Lettuce’s growth, implement diagnosis nitrogen, chlorophyll content of Brassica and Lettuce effectively via spectral reflectance model. The experiment shows the result:1.Brassica and Lettuce grow most robust in 8mmol/L nitrogen concentration solution, also the Photosynthesis、fluorescence and the output are the best. Brassica disposed by 22mmol/L nitrogen and Lettuce disposed by Ommol/L, have the lowest physical signs.2. Hyperspectral technology used on monitoring chlorophyll and nitrogen content was the fact of using spectral reflectance data in order to calculate total nitrogen and chlorophyll.Chlorophyll content of Brassica and Lettuce, leaf total nitrogen content and leaf spectral reflectance peak three had a positive correlation with each other. We establish a linear correlation between the regression model in different periods:on 14th day, Lettuce’s chlorophyll-spectral reflectance:Y=24.54224+0.89218x, Total nitrogen-Chlorophyll:Y=-7.5807+11.76019x; on 21th day, Brassica’s total nitrogen-Chlorophyll: Y=32.01062+1.99331x, Brassica and Lettuce’s total nitrogen-spectral reflectance:Y=-10.53557+ 0.50885x and Y=20.79385+5.16906x; on 28th day, Brassica’s chlorophyll-spectral reflectance:Y=-12.66836+1.03314x;The correlation between them is the strongest.3.Brassica and Lettuce’s most sensitive wave brands towards nitrogen are focusd on 500nm-650nm,550nm-600nm.550nm,600nm and 650nm are sensitive wave brands. Utilizing sensitive wave brands’reflection to diagnosis leaves’ chlorophyll content, total nitrogen via spectral index is more accurate.4.Brassica’s 21d wave brand has a stronger prediction to its production and fluorescence index.The model is Y=23.03236+134.24449x�'�Y=24.92090+0.010839x(2 mmol/L～12 mmol/L N treatment),Y=38.00253-0.0940x(12 mmol/L～22 mmol/L N treatment). Lettuce’s 21d NDVI has a stronger prediction to its production, the model is Y=0.00155+1.46250x.The 21d wave brands has a stronger prediction to its fluorescence index.Model is Y=24.49433+1.05671x(0 mmol/L-8 mmol/L N treatment), Y=0.00155+1.46250x(8mmol/L～20mmol/L N treatment) and Y=23.56538+0.03953x(0 mmol/L～8 mmol/L N treatment), Y=45.8088-0.01059x(8 mmol/L～20 mmol/L N treatment).