UNCORRECTED PROOF New district-level maps of rice cropping in India: A foundation for scientific input into policy assessment § Steve Frolking * , Jagadeesh Babu Yeluripati, Ellen Douglas Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH, USA Received 13 September 2005; received in revised form 9 January 2006; accepted 16 January 2006 Abstract We combined several district-level and state-level data sets of rice cropping in India to develop a single dataset of district-level rice cropping systems for all of India in 1999–2000. The data set contains district-level areas for 34 different single-, double-, and triple-cropping combinations (e.g., rice–rice, rice–rice–pulse, rice–pulse–fibrecrop, rice–wheat, and rice–fallow). The dataset specifies cropping by season (e.g., Kharif and Rabi) and area in two water management systems (irrigated or rainfed) for each cropping system in each district. The total rice sown area is 44.9 million hectares (Mha), 91% in the Kharif (wet) season. Total rice land area was 41.6 Mha, with upland rice accounting for 13% of this area. Rainfed rice (including upland and deepwater) accounted for 44% of the total rice sown area, and rice–fallow for 38% of the total rice sown area. The total multiple cropping area with rice occupied 17.6 Mha, with dominant systems being rice–wheat (8.8 Mha), rice–pulse (3.2 Mha), rice–rice (2.2 Mha), and rice–oilseed (1.2 Mha, including rice–groundnut). We combined these maps with a simple, monthly time-step water balance model to estimate irrigation water demand for irrigated rice by district; total national demand was 200 km 3 y 1 . A complete national, district-level set of maps and data of rice cropping systems and water management will be useful as inputs to a range of studies on agricultural productivity, resource use, and environmental impacts of rice agriculture. # 2006 Published by Elsevier B.V. Keywords: Rice paddy; Cropping area; Irrigation; Rainfed; Multiple cropping; Water use 1. Introduction Agriculture is a dominant form of human land use, with crop and pasture land occupying nearly 40% of the earth’s land surface (FAOSTAT, 2005). Conversion of natural landscapes to managed agriculture can have significant environmental impacts, including effects on floral and faunal biodiversity, the surface energy balance and weather, water use and the water cycle, nutrient cycling and nutrient leaching to groundwater and surface water, greenhouse gas emissions, and soil degradation (e.g., Vitousek et al., 1997; Matson et al., 1997; Goudie, 2000). With human population expected to increase by about 3 billion in the coming 50 years (Lutz et al., 2001), agriculture’s impact on the environment will continue to be large (Tilman et al., 2001). Quantifying and predicting these impacts requires both an understanding of and ability to model the relevant processes. Reliable and detailed multi- scale geo-spatial datasets of the distribution of agriculture and agricultural management practices are required. Rice is a dominant crop; about 20% of global total human food calories are supplied by rice (Maclean et al., 2002). More than 150 million hectares were sown with rice in 2002, 90% of that in Asia (Maclean et al., 2002). Demand for rice in Asia is projected to increase by 70% over the next 30 years (IRRI, 2002; Hossain, 1997). Rice agriculture is a major consumer of water. Agricultural water use accounts for about 70% of global freshwater consumptive demand globally, and 86% of Asia’s freshwater demand (FAO, 1999; IRRI, 2002). More than 90% of rice production in Asia is from flooded paddy fields (Huke and Huke, 1997). Flooded rice paddies contribute about 10% of total global emissions to the atmosphere of the greenhouse gas methane (Prather et al., 2001). www.elsevier.com/locate/fcr Field Crops Research xxx (2006) xxx–xxx 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 § Upon publication, the maps and data will be made freely available in several formats over the internet at http://www.eos-webster.sr.unh.edu. * Corresponding author at: Institute for the Study of Earth, Oceans and Space, 39 College Rd., University of New Hampshire, Durham, NH 03824, USA. Tel.: +1 603 862 0244; fax: +1 603 862 0188. E-mail address: steve.frolking@unh.edu (S. Frolking). 0378-4290/$ – see front matter # 2006 Published by Elsevier B.V. doi:10.1016/j.fcr.2006.01.004 FIELD 4645 1–14