Analysis of Optimum Growth Stages for Winter Crop Separability using Multi-Temporal NDVI Profiles in Vijapur Taluka, Gujarat State

Abstract

The multi-date Remote sensing satellite data has shown its great potential in agricultural applications. The crop monitoring throughout its growing season requires up-to-date and timely information for better crop growth management. In the present study analysis of growth stages of different winter crops grown in Vijapur Taluka was carried for determining optimum growth period for crop separability using multi-temporal NDVI profiles. The multi-temporal Sentinel-2 multi-spectral data (spatial resolution 10-m) covering study area for the winter crop period from November-2018 to March-2019 was downloaded from https://earthexplorer.usgs.gov/. Ground Truth (GT) data on winter crops grown in different villages of Vijapur Taluka was collected at multiple locations coinciding with different growth stages of winter crops. The spectral behavior of wheat, cotton, potato, fennel and castor crops during active growth stages was studied and it was observed that the spectral response of these crops is quite distinct. The maximum spectral difference was observed in the NIR spectral band as compared to other visible spectral bands of Sentinel-2 multi-spectral data. However, wheat and potato have almost similar spectral response during the month of January when wheat was at flag leaf to flowering stage and potato was at maximum vegetative growth stage. This suggests that, single-date Sentinel-2 multispectral digital data of active vegetative growth stages of these two crops during the month of January is not appropriate and sufficient for unique discrimination of wheat and potato. Therefore, Normalized Difference Vegetation Index (NDVI) profiles of these major winter crops were generated to monitor crop growth stages where maximum spectral differences can be observed. The results of NDVI growth profiles indicated that, during second fortnight of February wheat was grain filling and grain-milk stage and potato was at maximum vegetative stage with tuber maturity and at the same time other crops namely cotton, castor and fennel were at the maturity stages, have quite distinct NDVI values. During this period major winter crops with different growth stages in this study area will have quite distinct spectral behaviour which indicates that the period of second fortnight of February is quite appropriate and unique for discriminating these winter crops using single date satellite data.

Keywords

• Winter crops; Sentinel-2 Multi-spectral data;
• Spectral behaviour; Normalized Difference Vegetation Index (NDVI
• NDVI Growth profile; Crop Growth Stages

Supporting Institution

Department of Earth Science, School of Sciences, Gujarat University, Ahmedabad and Bhaskarcharya Institute for Space Applications and Geo-informatics (BISAG-N), Ministry of Electronics & Information Technology (MEITY), Government of India, Gandhinagar.

Project Number

1

References

1. Advanced Geospatial Technologies Foe Agriculture Monitering of Farmers"