Optimizing nutrient management strategies for rice–wheat system in the Indo-Gangetic Plains of India and adjacent region for higher productivity, nutrient use efﬁciency and proﬁts Vinod K. Singh a, *, Brahma S. Dwivedi b , K.N. Tiwari c , Kaushik Majumdar c , Meenu Rani a , Susheel K. Singh a , Jagadish Timsina d a Project Directorate for Farming Systems Research, Modipuram, Meerut 250 110, India b Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi 110012, India c International Plant Nutrition Institute (IPNI), South Asia Program, Gurgaon, Haryana, India d University of Melbourne, Victoria 3010, Australia A R T I C L E I N F O Article history: Received 19 November 2013 Received in revised form 12 May 2014 Accepted 13 May 2014 Available online xxx Keywords: Optimised nutrient supply Nutrient use efﬁciency Economic returns Rice–wheat system Indo-Gangetic Plain A B S T R A C T Rice (Oryza sativa L.)–wheat (Trititicum aestivum L.) system (RWS) in South Asia is under stress, as nutrient removals by crops are higher than their replenishment through fertilizers. We evaluated improved nutrient management strategies at 10 different locations across the Indo-Gangetic Plains (IGP) of India and adjacent regions during 2003–04 to 2005–06, and compared the improved practices in terms of yield gain, nutrient use efﬁciency and economic returns, with existing farmers fertilizer practices (FFP), and state recommended fertilizer rates by the government departments (SR). Improved N–P–K application rates were calculated by accounting for the indigenous nutrient supply (INS), yield target and crop nutrient demand as a function of the interactions between N, P and K. Compared with the SR and FFP, improved practices increased average grain yield from 0.32 to 3.03 t ha 1 and 1.37–3.69 t ha 1 in rice, and 0.49–1.17 t ha 1 and 0.71–2.26 t ha 1 in wheat across the locations, respectively. Added net return (in US $) from improved practices over FFP and SR under RWS ranged from 219.6 to 804.9 and from 104.3 to 599 ha 1 , respectively. Compared to improved practices, PFP N under SR and FFP were lower by 18.9 and 38.3% in rice, and 18.5 and 39.5% in wheat, respectively. Omission of P and K from improved nutrient management schedule resulted in yield loss of 0.6–2.8 t ha 1 in rice, and 0.43–1.84 t ha 1 in wheat, respectively. The annual removal of native P and K in the respective omission plots ranged from 21.8 to 46.1 kg P ha 1 and from 158.4 to 349.1 kg K ha 1 . Application of 26 kg P and 99 kg K ha 1 under improved practices had synergistic effect on nutrient use efﬁciencies viz. PFP N , AE P , AE K , RE P and RE K . Results suggested that optimised nutrient supplies considering crop nutrient needs and INS have potential for improving yields, nutrient use efﬁciency and proﬁts in RWS. The improved nutrient management strategy used in this study could be used in larger domains for improving cereal productivity, nutrient use efﬁciency and farm proﬁts. ã 2014 Published by Elsevier B.V. 1. Introduction Rice (Oryza sativa L.)–wheat (Trititicum aestivum L. Emend Fiori and Paol) system (RWS) is one of the pre-dominant agricultural production systems in the world, occupying 13.5 million hectares of cultivated land in the Indo-Gangetic Plains (IGP) in South Asia and several million hectares in China (Ladha et al., 2009). This provides food, income, and employment to ensure livelihood security for millions of rural and urban producers and consumers in South Asia. It is practiced on many soil types and under different ecologies ranging from coarse to ﬁne-textured soils under arid to semi arid climate of north-western India to sandy loam to clay soils under moist sub-humid to dry sub-humid climate conditions of the north-eastern India. Opportunities for area expansion are limited due to ﬁnite and often over-exploited natural resources (Timsina and Connor, 2001). Therefore, agronomic management has to be improved for greater efﬁciency of applied inputs to sustain yields of RWS (Yadav, 2003). Fertilizer use in the RWS is highly variable across the IGP with mean application rates of N + P 2 O 5 + K 2 O ranging from 258 kg ha 1 in the LGP to 444 kg ha 1 in the TGP (Sharma, 2003). On an average, * Corresponding author. Tel.: +91 121 2888548/9412578525; fax: +91 121 2888546. E-mail address: vkumarsingh_01@yahoo.com (V.K. Singh). http://dx.doi.org/10.1016/j.fcr.2014.05.007 0378-4290/ ã 2014 Published by Elsevier B.V. Field Crops Research 164 (2014) 30–44 Contents lists available at ScienceDirect Field Crops Research journal homepage: www.else vie r.com/locate /f cr