Spatio-temporal Assessment of Land Surface Temperature, Vegetation and Crop Water Stress for Sustainable Land Management in Upper Brahmaputra Valley, Assam

Land surface temperature (LST) and vegetation play a very significant role in influencing soil moisture and its interaction with the crop. Crop Water Stress Index (CWSI) is one of the most applicable indices to measure the level of water stress to crops that can be quantified using satellite imagery. The upper Brahmaputra river valley of Assam is a rapidly growing region experiencing extensive urban expansion, which necessitates the assessment of changes in spatio-temporal LST and vegetation dynamics for sustainable land management.

MODIS images were applied in this study to assess spatio-temporal LST, vegetation and Crop Water Stress (CWS). Normalized Difference Vegetation Index (NDVI) was adopted to assess the spatio-temporal vegetation dynamics. A correlation study was conducted to understand the relationship between LST, NDVI and CWSI.

It was observed that there was a strong negative correlation between LST and NDVI, whereas a strong positive correlation was found between LST and CWSI. Hotspot areas characterized by high temperature, low vegetation and high crop water stress were delineated in the ArcGIS platform. Between 2001 and 2021, all LST zones showed an increase in both maximum and minimum temperatures. Contour tilling, mulching and shade nets may effectively enhance soil moisture retention, fertility and microclimatic conditions in these hotspot areas.