<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu"^^ . "A research study was conducted at Tamil Nadu Agricultural University, Coimbatore\r\nduring kharif and rabi 2015 to estimate groundnut area, model growth and productivity and\r\nassess the vulnerability of groundnut to drought using remote sensing techniques.\r\nMulti temporal Sentinel 1A satellite data at VV and VH polarization with 20 m spatial\r\nresolution was acquired from May, 2015 to January, 2016 at 12 days interval and processed\r\nusing MAPscape-RICE software. Continuous monitoring was done for ground truth on crop\r\nparameters in twenty monitoring sites and validation exercise was done for accuracy\r\nassessment. Input files on soil, weather and management practices were generated and crop\r\ncoefficients pertaining to varieties were developed to assess growth and productivity of\r\ngroundnut using DSSAT CROPGRO-Peanut model. Outputs from remote sensing and\r\nDSSAT model were assimilated to generate LAI thereby groundnut yield spatially and\r\nvalidated against observed yields. Being a rainfed crop, vulnerability of groundnut to drought\r\nwas assessed integrating different meteorological and spectral indices viz., Standardized\r\nPrecipitation Index (SPI), Normalized Difference Vegetation Index (NDVI) and Water\r\nRequirement Satisfaction Index (WRSI).Spectral dB curve of groundnut was generated using temporal multi date Sentinel 1A\r\ndata. A detailed analysis of temporal signatures of groundnut showed a minimum at sowing\r\nand a peak at pod development stage and decreasing thereafter towards maturity. Groundnut\r\ncrop expressed a significant temporal behaviour and large dynamic range (-11.74 to -5.31 in\r\nVV polarization and -20.04 to -13.05 in VH polarization) during its growth period.\r\nGroundnut area map was generated using maximum likelihood classifier integrating\r\nmulti temporal features with a classification accuracy of 87.2 per cent and a kappa score of\r\n0.74. The total classified groundnut area in the study districts was 88023 ha covering 17817\r\nand 22582 ha in Salem and Namakkal districts during kharif 2015 while Villupuram and\r\nTiruvannamalai districts accounted for 22722 and 24903 ha respectively during rabi 2015.\r\nBlockwise statistics on groundnut area during both seasons were also generated.\r\nTo model growth and productivity of groundnut in DSSAT, weather and soil input\r\nfiles were generated using weatherman and ‘S’ build respectively besides deriving genetic\r\ncoefficients for CO 6, TMV 7 and VRI 2 varieties of groundnut.\r\nGrowth and development variables of groundnut were simulated using CROPGROPeanut\r\nmodel i.e., days to emergence (7-9 days) and anthesis (25-32 days), canopy height\r\n(63 to 70 cm), maximum LAI (1.12 to 3.07) and biomass (4176 to 9576 kg ha-1 across twenty\r\nmonitoring locations spatially. The resultant pod yield was simulated to be 1796 to 3060 kg\r\nha-1 with a harvest index of 0.28 to 0.43.\r\nOn comparison of LAI between observed (2.01 to 4.05) and simulated values\r\n(1.12 to 3.07) the CROPGRO-Peanut model was found to under estimate the values with R2,\r\nRMSE and NRMSE of 0.82, 1.10 and 34 per cent. However, the model predicted the biomass\r\nof groundnut with an agreement of 89 per cent through the simulated values of 4176 to9576\r\nkg ha-1 as against the observed biomass to 4620 to 9959 kg ha-1.\r\nThe simulated pod yields of groundnut in the study area were 1796 to 3060 kg ha-1 as\r\ncompared to the observed yields of 2115 to 2750 kg ha-1. The overall agreement between\r\nsimulated and observed yields was 84 per cent with the average errors of 0.81, 342 kg ha-1\r\nand 16 percent for R2, RMSE and NRMSE respectively.\r\nLAI values of groundnut, generated spatially through suitable regression models using\r\ndB from satellite images and LAI from DSSAT, ranged from 1.31 to 3.23 with R2, RMSE\r\nand NRMSE of 0.86, 0.78 and 24 per cent respectively on comparison with observed values.\r\nRemote sensing based spatial estimation resulted in groundnut pod yields of 1570 to 3102 kg\r\nha-1 across the study districts of Salem, Namakkal, Tiruvannamalai and Villupuram. In the\r\n20 monitoring locations, the pod yields were estimated to be 1912 to 2975 kg ha-1 as against\r\nthe observed pod yields of 1450 to 2750 kg ha-1 with a fairly good agreement of 80 per cent.\r\nThe vulnerability of groundnut was assessed using different drought indices viz., SPI,\r\nNDVI and WRSI. Considering SPI, out of the total groundnut area of 88023 ha, an area of\r\n86607 ha was found to be under near normal condition based on deviation of rainfall received\r\nduring cropping season from historical precipitation. Similarly NDVI, an indicator of\r\nvegetation condition during the cropping season, showed that 14272 ha of groundnut area\r\nwere under stressed condition during 2015.\r\nAn area of 40981 ha in Villupuram and Tiruvannamalai districts was found to be\r\nunder chances of crop failure based on Water Requirement Satisfaction index (WRSI). Major\r\ngroundnut areas of Salem district (14188 ha) was under medium risk zone.\r\nConsidering overall vulnerability, whole district of Villupuram was adjudged as\r\nhighly vulnerable to drought with regard to groundnut cultivation whereas four blocks of\r\nSalem, eight blocks of Namakkal and all the blocks of Tiruvannamalai were found to be\r\nmoderately vulnerable to drought."^^ . "2017" . . . . "Tamil Nadu Agricultural University Coimbatore"^^ . . . "Department of Agronomy Directorate of Crop Management, Tamil Nadu Agricultural University Coimbatore"^^ . . . . . . . . "M"^^ . "Deiveegan"^^ . "M Deiveegan"^^ . . . . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu (PDF)"^^ . . . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu (Other)"^^ . . . . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu (Other)"^^ . . . . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu (Other)"^^ . . . . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu (Other)"^^ . . . . . . "Mapping and modeling groundnut growth and productivity in rainfed areas of Tamil Nadu (Other)"^^ . . . . . 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