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The maize (Zea mays L.) - wheat (Triticum aestivum L.) cropping system (MWCS) could be better alternative to rice-wheat cropping system (RWCS), due to its lower water requirement, methane (CH4) emission and soil degradation. However, the global warming potential (GWP), greenhouse gas intensity (GHGi) and benefit cost ratio (BCR) of the MWCS need to be quantified in order to propose management practices for GWP mitigation. To achieve the objective of the study a field experiment was conducted at the ICAR-IARI, New Delhi during 2012-14. The experiment consisted of six treatments, viz. N0 (control), Urea, Urea+FYM, FYM, Urea+NI (nitrification inhibitor) and NOCU (neem oil coated urea). Two-year average results showed that as compared to urea treatment, GWP of MWCS lowered by 6, 16, 31 and 62% in urea+NI, NOCU, Urea+FYM and FYM, respectively. GHGi lowered by 6, 6, 24 and 46% in urea+NI, NOCU, Urea+FYM and FYM, respectively. The BCR was higher in NOCU and Urea+NI as compared to urea treatment; however, it was lower in FYM and urea+FYM. Thus, NOCU is capable for mitigating GWP and lowering GHGi with higher BCR from MWCS.

The Indo-Gangetic plains (IGP) of India are dominated by rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system (RWCS). Soil, climate, intensity and methods of rice and wheat cultivation differ in different parts of the IGP. So, the emission of greenhouse gases (GHG) will also differ. Present study quantified GHG emission and global warming potential (GWP) of RWCS of Haryana (Upper-IGP) and Bihar (Middle-IGP). A survey of rice-wheat growing farmers in three districts of Haryana (Kaithal, Karnal and Kurukshetra) and Bihar (Begusarai, Bhagalpur and Khagaria) was conducted. The survey data was used as inputs in InfoRCT model to simulate GHG emission in ricewheat systems of different districts. The selected areas in the IGP significantly differed in nitrogen, water and tillage inputs resulting in differences in emission of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) and the GWP. The simulated average GWP of conventional RWCS was 4268±179 kg CO2 equivalent/ha in Middle-IGP (Bihar) and 10605±680 kg CO2 equivalent/ha in the Upper-IGP (Haryana). However, with use of resource conserving technologies (RCTs) such as system of rice intensification (SRI), direct-seeded rice (DSR) and zero tillage wheat (ZTW), there was lowering in GWP than conventional puddled transplanted rice and tilled wheat. Rice had higher contribution than wheat towards GWP in both the states. The continuous flooded puddled transplanted rice (CFTPR), use of electric pump for irrigation and application of high amount of nitrogenous fertilizer were identified as main contributors of GWP. The site-specific intervention of RCTs may be recommended to reduce the emission of GHG in the RWCS in the IGP.

Climate is a very decisive factor in water resource availability of a region. Warming of the climate system in recent decades is evident from increase in global average air and ocean temperatures, widespread melting of snow and ice, and rising global sea level. The hydrological cycle is intimately linked with changes in atmospheric temperature and radiation balance. A warmer climate may lead to intensification of the hydrological cycle, resulting in higher rates of evaporation and increase of liquid precipitation. These processes, in association with a shifting pattern of precipitation, may affect the spatial and temporal distribution of runoff, soil moisture, groundwater reserves etc. and may increase the frequency of droughts and floods. Agricultural demand, particularly for irrigation water is considered more sensitive to climate change. A change in field-level climate may alter the need and timing of irrigation. Increased dryness may lead to increased demand, but demand may be reduced if soil moisture content rises at critical times of the year. It is projected that most irrigated areas in India would require more water around 2025 and global net irrigation requirements would increase relative to the situation without climate change by 3.5–5% by 2025, and 6–8% by 2075. The effect of climate change on water resources may be mitigated through better water harvesting through the creation of micro-storage facilities in watersheds. These would not only provide supplemental irrigation but also recharge the groundwater aquifers.

Abstract Background Rice is a major cereal crop and staple food of eastern India, and most farmers depend solely on rice for their livelihood. Rice farming provides both tangible and non-tangible benefits to ecosystems which need to be maintained and enhanced. These benefits are provided through ecosystem services (ES) that include both marketable and non-marketable. Methods In this study, the rice farms in eastern India were valued by quantifying the economic value of the services under conventional method of rice cultivation and the gap of ecosystem services value and farm income per unit area were assessed. A stratified random sampling technique was used in this study for selection of agro-climatic zones, districts, blocks, gram panchayat, and study units (households). Soil sampling was also performed for assessing the regulating services (biocontrol of pests, carbon flow, soil erosion, nitrogen fixation), provisioning services (food and by-products), and supporting services (soil fertility, hydrological flow, nutrient cycling, and soil formation). Results The results indicated that the total economic value of ecosystem services ranged from US$ 1238 to 1688 ha−1 year−1. The marketed (primary production) and non-marketed ecosystem services values ranged from 66–89 to 11–34% of the total, respectively. Valuation of some of the ecosystem services such as cultural services, biodiversity, and gas regulation, which may play a significant role in total ecosystem services, has not been made due to non-availability of data and appropriate methodology for rice ecosystem. Different values of parameters can explain the variability in ecosystem services among the agro-climatic zones in eastern India. Clustering of locations based on variability of ecosystem services helps in identifying intervention points for sustaining and improving ecosystem services, while permitting sustainable agro-ecological intensification. The highest total economic gap between ES value and farm income was found in the north central plateau zone (US$ 1063 ha−1 year−1) and the lowest in the north western plateau zone (US$ 670 ha−1 year−1). Conclusion We suggest various measures to reduce the economic gap, including payments for ecosystem services for rice farming for sustainability of the ecosystem and agricultural development, while ensuring reliable farm income.