Comparative Assessment of Projected Suitability of Finger Millet Crops in Tamil Nadu and Parambikulam Aliyar Basin Using ECOCROP Model: A Geospatial Approach

Abstract

Climate change is anticipated to pose extensive adverse effects on the range and suitability of various crop-growing areas across the tropics. The agro-climatic suitability of the finger millet (Ragi) crop in Tamil Nadu and Parambikulam Aliyar Basin (PAB) is simulated using an updated version of the FAO’s ECOCROP model integrated with DIVA-GIS software. The WorldClim dataset is used worldwide in climate change-related suitability studies. For this purpose, CCSM4 datasets, one of the global circulation models (GCMs) whose climate projections were employed in the IPCC's Fifth Assessment Report, are utilized based on RCP 2.6. The RCP 2.6 scenario projects an average global warming increase of around 1 ℃ by the end century. The results indicate that DIVA-GIS embedded in the ECOCROP model is an efficient tool in identifying the agro-climatic suitability of finger millet crops for the state as a whole and at the PAB basin scale. Changes in the current suitability (as a mean value for the period between 1970 and 2000) and future simulated suitability conditions for the year 2050 show that there may be a positive change of about 30–40% more areas under excellent future suitability class for the finger millet crop in the state and PAB. The findings reveal that Tirupur, the northern part of Krishnagiri, a small patch in Erode, parts of Kanyakumari, Thoothukudi, etc., have shown unsuitable or very marginally suitable for finger millet crops in the future under the purview of climate change. The places that are likely to be excellent for cultivation in the future are Nilgiris, southwest of Coimbatore, Theni, Dharmapuri, Salem, and north part of Namakkal. Vellore, Nagapattinam, Thiruvarur, Cudullore, Kancheepuram, Thiruvallur, and others come under excellent to very suitable categories. The outcomes from the secondary data analysis based on efficient cropping zones and ECOCROP model-based outcomes have been further evaluated for better comparative analysis. As per the current situation, most of the state districts fall under highly inefficient zones except 5–6. It is alarming to note that even though there is current climatic suitability as per ECOCROP, finger millet cultivation in coastal areas of Kancheepuram, Thiruvannamalai, Villupuram, Cuddalore, Ariyalur, Thiruvarur, and Nagapattinam is completely neglected. It is significant to note that currently, there are no most efficient cropping zone (MECZ) in the state. Hence, ample scope for wider scaling up of its cultivation. India, with its National Mission on Sustainable Agriculture and Food Security, is working toward food and nutritional security. Hence enhancing more areas under finger millets in suitable zones would be highly appreciated.