9 using approximate information of total irrigated area from national information and other data sources (irrigated area per national statistical unit, irrigated area from point, polygon, and raster maps of land cover and other satellite data) at a spatial resolution of 5-arc minutes. The Global Map of Irrigation Areas (GMIA) published by the FAO was developed by Siebert, et al. For instance, the USGS Global Land Cover Map 8 was developed using 1 km monthly composite of NDVI obtained from Advanced Very High Resolution Radiometer (AVHRR). During the past few years, several spatial data sets of irrigated area at global scale have been developed. The primary sources of irrigation data in India are the Directorate of Economics and Statistics of the Ministry of Statistics (DES), Ministry of Water Resources (MoWR), and Food and Agricultural Organization of United Nations (FAO). The current spatiotemporal extent of irrigated lands and inter-annual change at regional scales in India is still relatively uncertain and available maps are often outdated or prepared with spatially-coarse resolution data.
Monitoring irrigation water demands and consumption requires mapping irrigated areas either through agricultural census or using remotely sensing data. This revolution resulted in the agriculture sector benefiting from the introduction and expansion of different types of irrigation, fertilizers, and high yield crop varieties 4, 6, 7. A remarkable change in agriculture practices occurred in India after 1970, with a massive agricultural expansion called the ‘ green revolution’ 4, 6. In the future, the Indian region may experience stress to meet its water demand due to extreme weather and climate events such as droughts and heat waves, specifically in arid and semi-arid regions, where groundwater extraction is prominent for irrigation 3– 5. An increase in winter temperature, erratic monsoon season rainfall, extensive use of ground water resources, and absence of effective adaptation strategies are likely to negatively affect crop productivity 4, 5. However, agricultural production and food security are highly influenced by short-term weather anomalies, episodic extreme events, and long-term changes in air temperature and precipitation 3. In India, agriculture is the largest sector of employment and a significant fraction of total population depends on it for sustenance and economic livelihood through both traditional and modern agricultural practices 3. As a result, accurate information of irrigated agricultural water use and its spatial extent and variation is essential for water resource and crop productivity assessments. Irrigation practices can play a significant role in agriculture production to meet the projected food demand in several parts of the world by maintaining or increasing crop yields under changing climatic conditions.
Irrigation is estimated to use about 70% of world’s total available freshwater for food production using 18% of cultivated area globally 1, 2.
Irrigation water use is projected to increase under climate warming to maintain or increase agricultural production. High resolution (250 m) irrigated area maps showed satisfactory accuracy (R 2=0.95) and can be used to understand interannual variability in irrigated area at various spatial scales.ĭemands for fresh water during the twenty first century will continue to increase to meet the needs of a growing global population. The irrigated area maps were evaluated using the agricultural statistics data from ground surveys and were compared with the previously developed irrigation maps. Using 250 m normalized difference vegetation index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS) and 56 m land use/land cover data, high-resolution irrigated area maps are developed for all the agroecological zones in India for the period of 2000–2015.
However, annual, high-resolution irrigated area maps for India for an extended historical record that can be used for water resources planning and management are unavailable. Water resources planning and management in agriculture need spatially-explicit irrigated area information for different crops and different crop growing seasons. Under warming climate projections, irrigation frequency may increase leading to increased irrigation water demands. Irrigated area in India has increased substantially after the Green revolution and both surface and groundwater have been extensively used. India is among the countries that uses a significant fraction of available water for irrigation.