Abstract
The satellite data-based Normalized Difference Vegetation Index (NDVI) was used to assess the state of agriculture and crop vigour on a temporal basis to study agricultural vulnerability to climate change on a regional scale in a semi-arid red and black mixed soil region in Telangana, in the southern part of the Indian peninsula often referred to as the Deccan Plateau extend across 11.48 million hectares (mha) with 6.98 mha under rainfed agriculture. It provides a source of livelihood for 3.3 million farmers with small land holdings and 4.3 million farm labour and their dependants. The annual rainfall ranges from 600–1100 mm, of which 71% is received during the southwest monsoon period. Rainfed agriculture is the major land-use activity and increased climatic variability in recent decades has resulted in frequent losses, forcing governments to find suitable solutions. In order to understand factors that contribute to increasing agricultural variability in Telengana, and to understand trends in climatic variability and extreme weather events and their impact on agricultural production, time-series AVHRR NDVI data products were analysed and corroborated with the Standard Precipitation Index (SPI). The length of crop-growing period (LGP) was estimated from NDVI and studied as a Sensitivity Indicator for agricultural vulnerability, as it indicates crop health and vigour, which determine agricultural yield.
The results indicate which crops can be cultivated, which are vulnerable and the possible spatial extent of agricultural vulnerability based on an analysis on a regional scale, viz., the agro-ecological sub-region (AESR) delineated on the basis of agro-climatic parameters. This study belongs to the spatial vulnerability assessment category, and a lack of best practices in this field has been addressed using NDVI, SPI and LGP to test and verify their utility for assessing agricultural vulnerability. A methodology was developed to determine LGP from NDVI. The study’s results indicate that the northern and southern parts of Telangana registered a significant increasing trend in LGP, while major centrally located districts cultivating high-value crops like paddy, maize, sugarcane and cotton were vulnerable to reduction in LGP. Implementation of natural resource management interventions in harvesting of rainwater and supplementing irrigation to minimize crop losses would help reduce hardship and improve farmers’ adaptive capacity.
