  Citation: Bal, S.K.; Chandran, M.A.S.; Madhavan, S.V.; Rao,A.V.M.S.; Manikandan, N.; Praveen Kumar, R.; Parameswaran, P.V.; Attri, S.D.; Singh, P.; Mohanty, A.; et al. Water Demand in Maize Is Projected to Decrease under Changing Climate in India. Sustainability 2022, 14, 1419. https://doi.org/10.3390/su14031419 Academic Editor: Netrananda Sahu Received: 12 November 2021 Accepted: 19 January 2022 Published: 26 January 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Water Demand in Maize Is Projected to Decrease under Changing Climate in India Santanu Kumar Bal 1 , Malamal Alickal Sarath Chandran 1, * , Sandeep Vadakkemethel Madhavan 1 , Abburi Venkata Maruthi Subba Rao 1 , Narayanan Manikandan 1 , Ramagiri Praveen Kumar 1 , Pramod Valiyaparambil Parameswaran 1 , Shiv Dev Attri 2 , Priyanka Singh 2 , Ashutosh Mohanty 3, * and Vinod Kumar Singh 1 1 ICAR-Central Research Institute for Dryland Agriculture, Hyderabad 500059, India; santanu.bal@icar.gov.in (S.K.B.); vmsandeep@gmail.com (S.V.M.); avms.rao@icar.gov.in (A.V.M.S.R.); metsate@gmail.com (N.M.); ramagiri.praveen594@gmail.com (R.P.K.); pramodvp1@gmail.com (P.V.P.); vks.pdfsr@gmail.com (V.K.S.) 2 India Meteorological Department, Lodhi Road, New Delhi 110003, India; sdattri@gmail.com (S.D.A.); cpriyanka04@gmail.com (P.S.) 3 Faculty of Science and Technology, Madhyanchal Professional University, R&D Cell, Ratibad, Bhopal 462044, Madhya Pradesh, India * Correspondence: sarathagri@gmail.com (M.A.S.C.); drashutoship@gmail.com (A.M.) Abstract: Crop stage-specific information on the impacts of projected climate change on crop and irrigation water requirements are essential for improving productivity. This study investigated the possible implications of projected climate change on the phenology, effective rainfall (P eff ), crop (CWR) and irrigation water requirements (IWR) of maize in eight locations in India. CWR, P eff and IWR were estimated for seven crop stages viz., emergence, 5th leaf stage, tasseling, silking, milking, dough and maturity during the baseline (1980–2009) and near-century (2022–39) using climate data derived from a subset of 29 general circulation models. The results indicated that mean seasonal maximum temperature, minimum temperature and rainfall were projected to increase in all the locations. Hence, the total crop duration (3–7 days), CWR (8–69 mm) and IWR (1–54 mm) were projected to decrease. The study could identify the specific stages in which the greatest reduction in crop duration, CWR and IWR would occur. Such information will be of immense help to farmers and varietal improvement programs in the study regions in the near future. Keywords: GCMs; weighted average ensemble; phenology; effective rainfall; crop water requirement; irrigation water requirement 1. Introduction Water availability is critical for human settlement, agriculture production, and animal husbandry. Population growth, industrialization, and urbanization have all resulted in the increased use of water resources over the centuries. Due to these factors, the worldwide water demand has increased at a rate of 1% each year since 1980 [1]. Because of industrial and domestic needs, global water usage would grow by 20–30%, putting more than 2 billion people in high water stress and over 4 billion people in severe water scarcity for at least a month each year. Simultaneously, the United Nations’ Sustainable Development Goal-6 aims to ensure the availability and long-term management of water resources for all people everywhere [2]. In India, almost 81% of water resources are utilized by agriculture [3]. A rise in temperature as a result of global warming necessitates additional water for agriculture in order to meet crop evapotranspiration requirements [4,5]. The global mean surface temperature increased by 0.8–1.3 C between 1850 and 1900 and from 2000 to 2019, while global surface temperature is expected to continue to rise until the mid-21st century [6]. Sustainability 2022, 14, 1419. https://doi.org/10.3390/su14031419 https://www.mdpi.com/journal/sustainability