Spectral Response Of Different Crops At Various Growth Stages ...

International Journal of Applied Engineering Research, ISSN 0973-4562 Vol.7 No.11 (2012)© Research India Publications; http://www.ripublication.com/ijaer.htminitial stagecrop development stagemid-season stagelate season stageThe initial stage start from planting to the canopyconverges of about 10% of ground surface. In developed stageis about 70-80% effective ground cover. Mid-season stage tothe time of starting of maturity. Late season stage is from theend mid-season stage of full maturity of harvest the value ofKc for seasonal crops increase from initial low to plateau topeak plateau and decline during the late season stage. The Kcvalue during the initial period is profoundly influenced by thewetness of soil (due to irrigation of rainfall Kc value are highwhen the soil is wet and reduce sharply as the soil becomesdry.energy reflected from standard plate was ranging from 27 to143 W/cm2/sr-micron in (Table 1.3). Average energy reflectedfrom standard plate on different days. The energy increases upto 30 days and then fluctuates (75 to 105) but in decreasingorder up to 84 days. Then it again rises to a level of 105.However a definite pattern is obtained in this response thathigher is the wavelength i.e. band 1 to band 4 higher areenergy levels.The energy reflected from soil surface in the entiregrowth season of 126 days also follows the same pattern as ofstandard plate. Average reflectance of soil varies from 65 to66.94 percent in band 1 to band 4. The average energy levelsrising from band 1to band 4. It also indicates that reflectedenergy is having an approximately constant proportion to theincident energy i.e. soil behaves in similar manner with all thebands.The pattern of soil reflectance does not change withrespect to days after sowing depends on soil type, pigment ofsoil and soil moisture content. The radiation incident as wellas reflectance from soil & crop all has reduced which was dueto poor weather condition. This phenomenon can be observedthroughout the 4 band and the entire crop.Table 1.3(Observation on Energy reflected from Wheat crop)Fig.1.1 Crop coefficient of crops at different stageRESULTS AND DISCUSSIONTable 1.2 presents the field numbers, crop variety, sowing andharvesting dates in study aera. There are 11 fields wereregularly observedTable 1.2S.No. No. ofFieldsCrop Variety SowingdateHarvestingdate1 2 Wheat J-W- 30/11/09 02/04/101732 2 Mustard JG K3 30/12/09 20/03/103 2 Gram JB 1 20/11/09 30/03/104 2 Barseem JB 1 05/11/09 27/03/10Spectral response of different crops:The energy reflected from crop, soil and from calibration platewas measured in band1 (0.4-0.5µm), band2 (0.5-0.6µm),band3 (0.6-0.7µm) and band4 (0.7-1.1µm) using hand heldspectro radiometer. The observation of crop and soil weretaken at different interval till the harvesting of Mustard,Wheat, Gram and Barseem.Observation Date(Days aftersowing)15/12/2009(15)28/12/2009(28)12/01/2010(43)13/03/2010(103)20/03/2010(110)BandReflected Energy (W/cm²-Srmicron)Plate Soil Crop1 27.75 31.8 25.32 47.6 55.8 41.13 70.4 72.6 65.94 107.4 71.6 80.81 45.8 33.2 27.92 71.3 58.7 43.23 109.5 75.6 69.34 128.4 112.2 83.71 55.5 43.9 53.22 85.8 70.8 74.63 129.2 110.7 116.24 142.5 135.8 137.21 39.6 29.7 35.82 46.2 42.7 45.23 55.9 53.2 53.14 67.9 54.6 62.31 52.3 47.9 41.82 67.2 58.0 49.23 90.5 79.2 63.64 103.6 100.8 98.6Band 1 (0.4-0.5 µm), Band 2 (0.5-0.6 µm), Band 3 (0.6-0.7µm), Band 4 (0.7-1.1 µm)Energy incident and soil reflectance:Energy incident and soil reflection was observed from theentire field and averaged for analysis. Energy incident i.e. the

International Journal of Applied Engineering Research, ISSN 0973-4562 Vol.7 No.11 (2012)© Research India Publications; http://www.ripublication.com/ijaer.htmTable 1.4 (Observation on Energy reflected from mustardcrop.)Fig.1.2 Reflectance (%) of wheat cropTable 1.4(Observation on Energy reflected from Gram crop)ObservationDate(Days aftersowing)15/12/2009(25)28/12/2009(38)12/01/2010(53)13/03/2010(113)20/03/2010(120)BandReflected Energy (W/cm²-Srmicron)Plate Soil Crop1 55.5 32.6 54.62 58.6 50.4 55,93 143.8 76.8 123.64 171.5 110.4160.51 60.6 34.4 30.32 89.9 54.8 48.23 139.9 72.8 73.14 168.8 89.2 107.61 56.4 37.2 29.32 101.2 43.6 56.83 133.0 65.5 72.44 180.2 96.9 96.71 60.2 27.1 43.22 91.6 44.3 63.43 136.4 59.4 70.44 167.3 74.2 123.51 62.9 27.9 27.82 71.9 46.8 42.33 11.0 62.7 64.74 147.8 79.3 62.2Band 1 (0.4-0.5 µm), Band 2 (0.5-0.6 µm), Band 3 (0.6-0.7µm), Band 4 (0.7-1.1 µm)Observation Date(Days aftersowing)15/12/09(15)28/12/09(28)12/01/2010(43)Band13/03/2010(103)20/03/2010(110)Reflected Energy (W/cm²-Srmicron)Plate Soil Crop1 38.2 24.9 25.92 59.3 51.7 40.93 88.1 66.7 61.24 117.2 85.7 81.31 41.8 26.7 40.62 60.6 58.8 58.93 90.7 68.1 80.24 120.3 89.6 103.11 54.1 55.2 32.32 104.4 60.8 46.33 131.0 71.9 72.44 107.1 93.2 95.81 37.3 27.2 30.32 57.8 44.6 44.43 85.1 64.1 68.84 103.2 79.4 87.81 39.9 27.1 24.32 59.1 57.6 30.13 87.8 73.7 18.24 109.9 68.1 32.1Band 1 (0.4-0.5 µm), Band 2 (0.5-0.6 µm), Band 3 (0.6-0.7µm), Band 4 (0.7-1.1 µm)% reflectance120100806040200Mustard10 30 50 70 90 110 130Number of days after sowingFig.1.4 Reflectance (%) of Mustard cropBand1Band2Band3Band4Comparative Response of different bands:Incident energy levels are varying during crop growth periodand a part of it is reflected from crop. Spectral response ofdifferent crops (Mustard, Wheat, Gram and Berseem) wasstudied by comparing the percentage energy reflectance indifferent spectral bands namely Blue, Green, Red and NIRwave lengths during the crop growth period. Percentagereflectance and derived vegetation indices namely NDVI, RVIand SAVI for all the days of observation on different crops.Fig.1.3 Reflectance (%) of Gram crop