Potential yield challenges to scale-up of zero budget natural farming

We thank V. Kumar, Z. Hussain and R. Nalavade of RySS for information, support while visiting sites and discussions. Funding for this work was provided by the Newton Bhabha Virtual Centre on Nitrogen Efficiency in Whole Cropping Systems (NEWS) project no. NEC 05724, the DFID-NERC El Niño programme in project NE P004830, ‘Building Resilience in Ethiopia’s Awassa Region to Drought’ (BREAD), the ESRC NEXUS programme in project IEAS/POO2501/1, ‘Improving Organic Resource Use in Rural Ethiopia’ (IPORE), and the GCRF South Asian Nitrogen Hub (NE/S009019/1). J.Y. was supported by the Scottish Government’s Rural and Environment Research and Analysis Directorate under the current Strategic Research Programme (2016–2021): Research Deliverable 1.1.3: Soils and Greenhouse Gas Emissions. The input of P.S. contributes to the UKRI-funded projects DEVIL (NE/M021327/1), Soils-R-GRREAT (NE/P019455/1) and N-Circle (BB/N013484/1), the European Union’s Horizon 2020 Research and Innovation Programme projects CIRCASA (grant agreement no. 774378) and UNISECO (grant agreement no. 773901), and the Wellcome Trust-funded project Sustainable and Healthy Food Systems (SHEFS).Peer reviewedPostprin

CCAFS-MOT - A tool for farmers, extension services and policy-advisors to identify mitigation options for agriculture

This work was implemented as part of the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), which is carried out with support from CGIAR Fund Donors (RG12839-10) and through bilateral funding agreements. For details please visit https://ccafs.cgiar.org/donors. The views expressed in this document cannot be taken to reflect the official opinions of these organizations. This work has also been partially funded by the UK Natural Environment Research Council (NERC).Peer reviewedPublisher PD

A global methane model for rice cropping systems: Final Report

It has been estimated that rice production accounts for up to 55% of the total greenhouse gas (GHG) emissions budget from agricultural soils. Finding efficient ways to mitigate these emissions without adversely impacting yield is crucial as rice is a major cereal crop for half of the world’s population and with production being estimated to increase by up to 40% by 2040 to meet demands. Emissions are challenging to measure and thus finding field-specific mitigation options is difficult; many therefore rely on GHG tools to explore suitable mitigation strategies. We have collected field data from across the world from peer- reviewed publications pre-2021, by evaluating the influence of different factors on methane (CH4) fluxes, and using a step-down approach, a new CH4 model was created using the linear mixed model in Rstudio. The new model has five additional factors and uses a different climate classification compared to existing models. Baseline emission factors (EFs) were estimated using the predicted data. Result shows that the difference between tropical and temperate regions needs to be considered when calculating an EF. By having different pre- season water management as a baseline, more accurate EFs can be estimated, particularly for temperate and American rice regions as the existing EF uses a baseline of short drainage, which is not common in these regions that typically have a long drainage duration and only one rice crop cycle per year. Evaluation of the new model against existing models shows the new model performs better, with R values of 0.602 while other models produce R2 in the range of 0.11-0.37. The new model could be more sensitive to capture management practice differences between tropical and temperate rice and their impact on CH4 emission. Keywords: Agriculture; climate change; food systems; food security; rice; methane; greenhouse gas emissions

Science-based GHG emissions targets for agriculture and forestry commodities

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Treatment of organic resources before soil incorporation in semi-arid regions improves resilience to El Niño, and increases crop production and economic returns

We are grateful for support from the DFID-NERC El Niño programme in project NE P004830, “Building Resilience in Ethiopia’s Awassa region to Drought (BREAD)”, the ESRC NEXUS programme in project IEAS/POO2501/1, “Improving organic resource use in rural Ethiopia (IPORE)”, and the NERC ESPA programme in project NEK0104251 “Alternative carbon investments in ecosystems for poverty alleviation (ALTER)”. We are also grateful to Anke Fischer (James Hutton Insitute) for her comments on the paper.Peer reviewedPublisher PD

Which agroforestry options give the greatest soil and above ground carbon benefits in different world regions?

Climate change mitigation and food security are two of the main challenges of human society. Agroforestry systems, defined as the presence of trees on external and internal boundaries, cropland, or on any other available niche of farmland, can provide both climate change mitigation and food. There are several types of agroforestry systems with different rates of above ground and soil carbon (C) sequestration. The amount of carbon sequestered can depend on the type of system, climate, time since land use change and previous land use. Data was collected from a total of 86 published and peer reviewed studies on soil and above ground carbon sequestration for different agroforestry systems, climates and regions in the world. The objective was to understand which agroforestry systems provide the greatest benefits, and what are the main factors influencing, soil and above ground carbon sequestration. The results show that, on average, more soil carbon sequestration occurs in agroforestry systems classified as silvopastoral (4.38 tC ha−1 yr−1), and more above ground carbon sequestration occurs in improved fallows (11.29 tC ha−1 yr−1). On average, carbon benefits are greater in agroforestry systems Tropical climates when compared to agroforestry systems located in other climates, both in terms of soil (2.23 tC ha−1 yr−1) and above ground (4.85 tC ha−1 yr−1). In terms of land use change, the greatest above ground carbon sequestration (12.8 tC ha−1 yr−1) occurs when degraded land is replaced by improved fallow and the greatest soil carbon sequestration (4.38 tC ha−1 yr−1) results from the transition of a grassland system to a silvopastoral system. Time since the change is implemented was the main factor influencing above ground carbon sequestration, while climate mainly influences soil carbon sequestration most. The results of the analysis may be used to inform practitioners and policy makers on the most effective agroforestry system for carbon sequestration. The lack of data on carbon stocks before the implementation land use change and the lack of reporting on soil sampling design and variances were the main limitations in the data. The need to report this data should be considered in future studies if agroforestry systems are expected to play an important role as a climate change mitigation strategy

More crop per drop:exploring India’s cereal water use since 2005

This study forms part of the Sustainable and Healthy Diets in India (SAHDI) project and the Sustainable and Healthy Food Systems (SHEFS) programme supported by the Wellcome Trust’s Our Planet, Our Health programme [grant numbers: 103932/Z/14/A and 205200/Z/16/Z]. The Wellcome Trust had no role in the design, analysis or writing of this work. Carole Dalin was supported by the Natural Environment Research Council Fellowship (NERC NE/N01524X/1). The authors acknowledge Dr. S.K. Ambast, Director, ICAR-Indian Institute of Water Management, Bhubaneswar, India and his scientific colleagues for their insightful review of early results of this study.Peer reviewedPublisher PD

Greenhouse gas mitigation in Chinese agriculture:Distinguishing technical and economic potentials

International audienceChina is now the world's biggest annual emitter of greenhouse gases with 7467 million tons (Mt) carbon dioxide equivalent (CO2e) in 2005, with agriculture accounting for 11% of this total. As elsewhere, agricultural emissions mitigation policy in China faces a range of challenges due to the biophysical complexity and heterogeneity of farming systems, as well as other socioeconomic barriers. Existing research has contributed to improving our understanding of the technical potential of mitigation measures in this sector (i.e. what works). But for policy purposes it is important to convert these measures into a feasible economic potential, which provides a perspective on whether agricultural emissions reduction (measures) are low cost relative to mitigation measures and overall potential offered by other sectors of the economy. We develop a bottom-up marginal abatement cost curve (MACC) representing the cost of mitigation measures applicable in addition to business-as-usual agricultural practices. The MACC results demonstrate that while the sector offers a maximum technical potential of 402 MtCO2e in 2020, a reduction of 135 MtCO2e is potentially available at zero or negative cost (i.e. a cost saving), and 176 MtCO2e (approximately 44% of the total) can be abated at a cost below a threshold carbon price ≤¥ 100 (approximately €12) per tCO2e. Our findings highlight the relative cost effectiveness of nitrogen fertilizer and manure best management practices, and animal breeding practices. We outline the assumptions underlying MACC construction and discuss some scientific, socioeconomic and institutional barriers to realizing the indicated levels of mitigation