| ?Objective?Through the analyseds spring corn canopy structure characteristics,canopy LAI,yield and high spectral correlation under the different density in xinjiang region,established hyperspectral monitoring model which from the canopy LAI and yield of spring corn under different density,it was provides the basis for monitoring the growing and yield of spring corn in xinjiang region.?Method? Field trials were carry out under different spring maize varieties and different density level in xinjiang,they were measureed which were the canopy spectral reflectance,leaf area index,leaf area and biological yield,plant height,ear position,economic output,etc.The correlation was analysied which of cumulative leaf area index,relative density of leaf area,biological yield,economic yield and high spectral under different density and,the leaf the models of area index,relative leaf area density,biological yield and economic yield were established and the precision of them were tested.?Results?the results were as follow:1)With the increase of density,the longest and most wide blade leaves of maize were remain roughly the same,blade width decreased significantly with the increased of density,and longest leaves first increased than decreased with the increased of density;Plant leaf area reduced,basal leaves(1-6 leaf)area changed little,lower leaves(7-12 leaves)area increased than decreased,and middle leaves(13-16 leaf)area show the differences between these different inter-annual,upper leaves(17 leaves and above)area gradually decreased;leaf area of whole canopy increased and relative differences;Stem dry weight differences,leaf weight difference was smaller.Under the D3 density,high economic yield and ear position,relative leaf area density were positively correlated,and the biological yield present negative correlation,significantly less than 0.05.2)Under different density,estimation models of leaf area index and relative leaf area density were different in spring maize.High spectral estimation models of leaf area index,which were y = 0.0014 x2+0.1201x+2.1747(R2 = 0.73),y = 30.405x2+10.122x+ 6.2617 x(R2 =0.47),y = 965.98 x2-285.68x+29.929(R2 = 0.66)were best in D1,D2 and D3 density,RMSE were 0.73,0.34,0.1,respectively.Relatively high spectral estimation model of leaf area density,which were y = 19.588 x2+31.649(R2 = 0.741),y = 26.266 x2+26.266 x+10.726(R2 =0.566),y =-2207.436 x2+ 538.426 x-538.426(R2= 0.852),in D1,D2 and D3 density.RMSE were 0.82,2.45,0.41,respectively.3)Under different density,estimation models of Biological yield were different in spring maize.Biological yield of high spectral estimation model in D1,D2 and D3 density on NDVI[719,1080],R615,DVI [1020,671] fitting estimation model y=75.205e2.668x(R2=0.86),y=-13894.287x2+1651.835x+ 110.938(R2= 0.71),y=120.438 x2-44.535x+95.499(R2= 0.75)thehighest precision,RMSE were 1.99,3.61,2.37.Economic yield of high spectral estimation model in D1,D2 and D3 density with DVI [691,401],DVI [1102,533],NDVI [1122,780]fitting estimation model y = 1004.37e-0.716x(R2=0.721),y=21255.197x2-22028.232x+6757.953(R2=0.723),y=1122.356+19.933lnx(R2 = 0.652),the highest precision,RMSE were 1.24,1.13,2.37. |
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