Reduce rice cultivation emissions via integrated methods

Rice is a staple crop for over 3.5 billion people globally, contributing over 50% of the caloric intake in the Asian Region (1). In addition, forecasts show that global rice demand will continue to rise with growing populations (2). Simultaneously, rice paddies account for 48% of greenhouse gas (GHG) emissions from croplands (3). Rice cultivation is a significant anthropogenic source of atmospheric methane (CH4) and nitrous oxide (N20) emissions when conventional water, nutrient, and plant management techniques are applied, accounting for ~13% of global food system emissions, and ~2% of global GHG emissions as illustrated in Figure 1 below. (4) CH4 emissions are associated with anaerobic decomposition of vegetation in continuously flooded fields. N20 emissions are largely associated with nitrogen (N) fertilizer and irrigation management, as well as N20 emitted by the soil and rice plant (5). Rice production is highly concentrated in China and India, who are responsible for 23% of the 1.3 GtCO2e of annual global estimated emissions from rice. (6)

Emissions from rice cultivation are caused and influenced by several factors. Water management, planting and tillage practices, cultivar, fertilizer and pesticide use are all key factors of emissions, and of mitigation potential. In flooded rice paddies, the continuous water blocks oxygen from penetrating the soil, creating anaerobic environments for methane-producing microbes (7). Another contributing factor is improper management of residues such as rice straw and husks. Common farmer practice consists of either leaving this residue material to be submerged, where they then decompose and release methane, or burning it, which releases carbon dioxide and soot. Improved rice cultivation systems present a significant opportunity to reduce GHG emissions in row crop agriculture.

Figure 1: Annual global anthropogenic methane emissions and food system emissions. Combined, waste and rice cultivation account for more than 70-75% of food system methane emissions.

Source: Global Methane Hub, Climate Works Foundation. GINA Food System Methane Technical Report, 2023.

Improved rice cultivation methods exist that enable significant reductions in emissions and water use. Additionally, sustainable rice production systems have been shown to decrease emissions while creating farm and landscape value as well as equity and nature co-benefits such as increased soil health, biodiversity, and ecosystem services.

In 2021, 150 nations signed on to the Global Methane Pledge (GMP) led by the United States and the European Union – a global voluntary commitment towards a collective reduction in global methane emissions by at least 30% of 2020 levels by 2030. Beyond reducing their carbon footprints, companies working to reduce their methane emissions are placing themselves ahead of potential regulatory requirements put in place at a national level.

Given the high GHG emissions from rice production, reductions can contribute significantly to country’s NDCs and to the Global Methane Pledge. (8)

Sustainable rice production techniques involve both a set of management practices and direct mitigation, as described below and as exemplified in Figure 3.

Sustainable management practices include:

• Rice paddy water management: single and multiple rounds of draining of paddy fields (e.g., mid-season drainage) and alternative wetting and drying (AWD)

• Rice straw management: long intervals between straw incorporation and flooding during rice growing season; application of composted rice straw; involving re-purposing the residue for other on-farm uses instead of burning or leaving it in-field

• Direct Seeded Rice (DSR): rice seed sown/sprouted directly into (dry) field, rather than transplanting, saving water and avoiding flooding conditions that generate methane

• Agrochemical management, and a more balanced application of nutrients

• Agroecological and regenerative practices, such as seeding rice without tilling the ground (regenerative agriculture principle of no till)

Direct mitigation technologies include:

• Low-methane varietal rice selection: planting short duration varieties reduce methane while maintaining yields

• Methane inhibiting fertilizers: application of fertilizers with higher amounts of ammonium phosphate sulfate fertilizer inhibit methane via sulfate-reducing microorganisms outcompeting methanogen (9)

Sustainable Rice Cultivation approaches

Although there are multiple systems and approaches to sustainable rice cultivation, the Sustainable Rice Platform (SRP) is one established example of a comprehensive, credible, verifiable and systematic approach to sustainable rice cultivation that results in quantified sustainability outcomes.

As explained in Figure 2 below, the SRP Standard for Sustainable Rice Cultivation involves 41 requirements structured under 8 themes, as depicted below.

Figure 2. Themes and requirements in the SRP Standard for Sustainable Rice Cultivation.

Source: Sustainable Rice Platform Standard for Sustainable Rice Cultivation (Version 2.2) (10)

These SRP requirements all prioritize cultivation practices that are adapted to the local agroecological, biophysical and socioeconomic context – including improved nitrogen fertilizer and nutrient management, better stubble management, diversified rice varieties and more diversified cropping systems when feasible. Many of these practices are based on principles that are scale-neutral, enabling producers to adapt and respond to local conditions and as such can be implemented at smallholder level to medium- and large- scale production.

Globally, there is increasing awareness, intention, and ambition of major Consumer Packaged Goods (CPG) companies to transition their rice supply chains to be sustainable and regenerative.

For example, Nestlé is implementing regenerative practices in their rice supply chain to lower their carbon footprint in rice farming. In partnership with IndigoAg, Nestlé conducted a pilot with farmers in Arkansas, USA who produce rice for their Gerber brand. The implementation of regenerative agriculture practices included minimizing tillage, alternate wetting and drying irrigation (AWD), precision drone-controlled crop spraying, and furrow irrigation. The desired outcomes of reduced emissions, fertilizer and water use were achieved without reduction in yield.

Mars, Inc., as owner of the world’s largest global rice brand Ben’s Originals, is a member of the Sustainable Rice Platform (SRP), and has committed to sourcing 100% of its rice certified by the SRP Standard. As of 2019, the company reported to be sourcing 97% of its rice in this way – up from 63% in 2016 (11). After supporting the introduction of AWD to rice farmers in Pakistan, Mars reported a 32% increase in income and 17% increase in crop yield among participating farmers.

Climate impact

Targeted emissions sources Sustainable rice production targets CH4 and N20 emissions, primarily. There are also reduced C02 emissions from avoided rice stubble burning and increased soil organic carbon sequestration.

• Scope 1 (farm owners): Reduced emissions from fertilizer use (N20), practice changes (CH4 and CO2), and low methane crop varieties.

• Scope 2: (farm owners): Reductions in energy as processes become more efficient and less use of machinery in the case of some regenerative and agroecological practices (no till, for example).

• Scope 3 (companies purchasing sustainable rice products):

  • Category 1 (Purchased goods and services)

  • Category 3 (Fuel- and energy-related activities not included in scope 1 or scope 2)

Rice cultivation has been estimated as having the second highest mitigation density of all agricultural mitigation actions, based on its technical potential versus cost effective potential during the period 2020 to 2050 (12). Emissions from rice production will differ significantly depending on farm-size, region, or country, requiring low emissions rice production system solutions to be applicable at different scales and regional contexts.

For scope 1, reduction potential of practice changes at farm level such as the implementation of Alternate Wet and Drying (AWD) can result in up to a 48% reduction of methane emissions. (13) See section Read more for more information about AWD.

Decarbonization impact

Rice cultivation has been estimated as having the second highest mitigation density of all agricultural mitigation actions, based on its technical potential versus cost effective potential during the period 2020 to 2050 (14). Emissions from rice production will differ significantly depending on farm-size, region, or country, requiring low emissions rice production system solutions to be applicable at different scales and regional contexts.

For scope 1, reduction potential of practice changes at farm level such as the implementation of Alternate Wet and Drying (AWD) can result in up to a 48% reduction of methane emissions. (15) See section Read more for more information about AWD.

Business impact

Benefits

The transition to sustainable rice cultivation can generate positive impact for businesses beyond climate. Business implications can include (16)

• Increased crop yield or quality: due to best practices, improved soil health, and rice cultivars

• Reduced costs: from lower seed and pesticide use

• Reduced labor costs: through best practices and capacity building

• Increased farm income: through reduced agrochemical use and associated costs, best practices, resource-use efficiency and increased yields. According to SRP, on average farmers who adopt the SRP Standard earn a 10% higher net income (17)

For farmers adopting a certified method such as producing SRP verified rice, there may be additional benefits such as:

• Enhanced access to new markets and customers: as farmers will benefit from the SRP Standard and Assurance Scheme label

• Increased public trust: as opting for SRP Standard verification is a demonstrate sustainability commitment

Costs

General cost considerations when implementing this solution:

• Operating costs can be lowered over the long run but may also come at a transition cost:

  • Cornell University states that best practices (such as part of the System of Rice Intensification SRI methodology (18) can lead to a 80-90% reduction in seed use, and up to 50% water saving[i]

  • When looking at regenerative agriculture overall, operating costs are likely to increase initially but are also likely to return to previous (normalized) levels or lower in a few years. Additionally, regenerative agriculture can increase profitability after 3-5 years. However, farmers could face significant early financial risk and may require transition cost support

• Investment costs can vary depending on regional differences and the specific practices implemented:

  • Many best practices that improve yields/efficiencies, thereby reducing methane emissions per unit of food produced, are management practices that leverage existing technologies and can be cost-saving or low cost, but face diffusion barriers due to lack of awareness or incentives (19), and also the need for training farmers in practices, for example, AWD.

  • Investment in training and extension services for farmers may be a necessary investment consideration.

  • Investments in agricultural infrastructure may also be a necessary investment consideration, for example, irrigation infrastructure.

Impact beyond climate and business

Co-benefits

Sustainable rice generates multiple co-benefits beyond business and climate relating to the Just Transition and nature.

Just Transition

Equity co-benefits include strengthening farmer livelihoods through increased farm income from higher yields or quality and reduced costs at production level (on seed and agrochemicals), simultaneously contributing to enhanced quality of life.

• Cornell University asserts that SRI paddy rice usually produces about 10% higher outturn of polished rice when milled, because of fewer unfilled grains and less chaff. Fuller grains, reduced chalkiness and reduced breakage of grains during milling, further improves grain quality, which translates often in a higher price and return for the farmer (20).

• Sustainable rice can improve farmers’ food security, by guaranteeing long-term productivity, providing opportunities for diversifying income streams, and increasing resilience to climate change; as well as making major contributions to ecosystem maintenance (21).

Nature

Conventional rice farming practices that are water and agrochemical intensive are a significant driver of habitat and biodiversity loss and degradation in a range of natural ecosystems including wetlands, grasslands, and forests. For example, floodplain wetlands, seasonally flooded grasslands, and swamp forests have been converted to rice paddies in the Mekong Delta region of Vietnam (22).

• Transitioning to sustainable, low methane rice production systems would secure significant nature co-benefits: along with conserving and restoring ecosystems, the SRP Standard and regenerative practices such as no till soil management improve soil health by supporting microbial abundance and diversity, and reduce water use and pollution (22).

• Maintenance of rice cultivar biodiversity is enhanced, as local varieties become more productive and attractive for farmers to grow.

Figure 3 below shows the co-benefits of sustainable rice practices, ascribing certain environmental and economic benefits to each specific method, such as improved biodiversity, soil conservation, increased yield, less agrochemical inputs, and less labor.

Source: Asia Rice Nature-Based Solutions Accelerator Baseline Report

Potential side-effects

Practices that solely address mitigating methane emissions can and may increase N20 emissions. An example is AWD whereby experimental results from Kritee et al. (2018) suggest that the Indian subcontinent’s N20 emissions from intermittently flooded rice fields could be 30-45 times higher than reported under continuous flooding (23).

This complexity and relationship between emissions calls for an integrated, holistic approach that takes into account emission trade-offs, flows, and overall net balance in a comprehensive way, such as improved fertilizer and pesticide management. Therefore co-management of water, nitrogen, and carbon is recommended to reduce the net climate impact of rice cultivation (24).

Typical business profile

Companies across the rice value chain, from producers to processors to traders, CPG food brands, and retailers, can benefit from sustainable rice production.

Approach

In 2015 the Sustainable Rice Platform (SRP) developed the world’s first voluntary sustainability standard for rice which represents the implementation of best practices in rice cultivation. The SRP Standard for Sustainable Rice Cultivation details what is required to be implemented.[LA1] Additionally, the SRP Standard offers a working definition of rice sustainability, and a normative framework that can serve as a basis for supporting claims to sustainability performance in rice supply chains. The SRP Performance Indicators for Sustainable Rice Cultivation allow for quantitative measurement and assessment of the sustainability impacts of adoption of recommended practices at farm level. The Standard applies to all farm-level processes in rice production, including post-harvest processes under the farmer’s control.

Sustainability certification schemes are a distinctive method for boosting the uptake of sustainable best practices throughout agricultural value chains, as they provide factors such as production standards, guidance, traceability, assurance and incentive mechanisms to producers which can facilitate the implementation of improved production methods.

The key steps to impact, according to SRP, are action and accountability. To this end, SRP created a system called the SRP Assurance Scheme, which allows rice value chain actors to demonstrate compliance with the SRP Standard at various levels on the journey to certification, as well as impact measured by the SRP Performance Indicators. On average, farmers who adopt the SRP Standard earn 10% higher net income, reduce water use by 20%, and cut greenhouse gas emissions by up to 50%.

It involves rules for proving compliance with the SRP Standard for Sustainable Rice Cultivation by offering 3 levels of assurance – self-assessment, second party verification and third party verification, respectively. This system addresses key stakeholder actions and needs that mutually reinforce each other toward transforming the global rice sector towards sustainability (25):

• Farmers: require shifting to proven, climate-smart best practices and the technical and economic support to do so

• Buyers: require a way to verify these changes in order to support a sustainable sourcing claim

• Consumers: are empowered to improve the livelihoods of small farmers and the health of agroecosystems by purchasing verified sustainable rice

At the core of SRP is the provision of capacity building and technical assistance, an essential part of the approach to empower rice-growing communities to continue implementing sustainable production methods over the long term. A step-by-step guide to getting SRP-certified facilitates companies interest in understanding how to become certified and implement sustainable rice standards.

Stakeholders involved

As well as the key actors mentioned above, an array of stakeholders are involved in the implementation of regenerative and sustainable rice production practices and to create enabling conditions for sustainable rice value chains:

• Input companies: to have agrichemical and seeds companies on board with a holistically sustainable approach and shift their products and services to be in alignment with sustainable standards

• Retailers and brands: to encourage and incentivize market demand for sustainable rice and sustainable rice products

• Marketing: to develop marketing campaigns that raise consumer awareness about the sustainability issues and opportunities around rice, and that target the consumers’ desire to support farmers and sustainability efforts of a product otherwise poorly known to be an impact commodity with significant mitigation potential

• Whole value chain collaboration: to facilitate uptake and collaboration across the main categories of the entire rice value chain from production to processing to commercialization and the respective stakeholders (input and service providers, medium to large farms and farmer groups, smallholder rice growers; collectors, millers, and processors; traders, retailers, and brands)

• Public/private funders and investors: to ensure long-term and stable financial sustainability and support

• Public sector: to engage with governments to create enabling conditions through regulations and incentives, and to support agricultural extension services, for more sustainable rice production

Key parameters to consider

Many best practices are well established, while other rice cultivation methane innovations are still emergent, as highlighted in the table below, which can help support decision-making for effective and regionally relevant implementation.

Figure 4. Rice cultivation innovation prioritization table

Source: GINA Global System Methane Technical Report, 2023

Implementation and operations tips

There are various implementation and operations considerations, including:

• The provision of capacity building and technical assistance which empowers rice-growing communities, are essential to sustainable production method implementation over the long term.

• Women farmers in Southeast Asia make up to 60% of the required labor, and up to 80% in South Asia (26). In rice production, approximately half of the estimated 144 million smallholder farmers are women (27). Women’s empowerment is vital, therefore, to the implementation and scaling up of sustainable rice. This includes women’s access to finance, training and decision-making (28).

• Sustainability schemes such as the SRP Standard referenced above can accelerate adoption of sustainable rice production practices and with verifiable evidence of positive impacts from the uptake of sustainable rice production practices. At the same time, demand for SRP-certified rice is not yet widespread. The benefits of SRP-certified rice, for example, should be promoted to increase regional consumer demand for sustainable rice, and incentivize farmer uptake of the certification.

• The sustainability of rice-based production systems also depends on the health of the landscapes of which they form an intrinsic part. In particular, watershed wetland and forest ecosystems are vital in ensuring the stability of rice paddy system water supplies. Expansion of rice production areas into natural areas results in biodiversity loss and can negatively affect the provisioning of ecosystem services (including carbon sequestration). It is therefore important to prevent further conversion of natural habitats for rice farming and mitigate the impacts of conventional rice production in existing rice farmlands (29).

• Relevant financing mechanisms and supporting policies to create enabling conditions for sustainable rice production systems.

Footnote (looking forward)

In November 2023, WBCSD launched the Mission paper for the RICE+ hub for regenerative ricescapes, in collaboration with member companies and partners, under the auspices of the Sustainable Rice Landscapes Initiative (SRLI).  The Mission paper is a call to action to bring together committed companies to drive an action-oriented agenda to tackle the major challenges that inhibit investments in scaling sustainable and regenerative rice-based landscapes (regenerative ricescapes, for short).  Companies will collaborate to forge public-private investment alliances, adopt high-integrity rice carbon and sustainability standards, facilitate knowledge exchange and promote innovations. Committed companies must establish relevant targets and action plans that they measure and disclose in a credible and transparent manner, and that make a demonstrable contribution to sustainable and regenerative rice production systems and landscapes. More information:

More Information: AWD & DSR

Alternate Wetting and Drying (AWD) is an example of a management practice for irrigated lowland rice that saves water and reduces methane emissions while maintaining yields. AWD entails periodic draining of the field to a certain threshold, usually 15 cm below the soil surface, and re-flooding. During the dry phase this inhibits methane-producing bacteria, reducing methane emissions. On-farm tests with AWD have shown reductions in methane emissions by 20–70%. IPCC 2006 Guidelines for National Greenhouse Gas Inventories estimate a 48% reduction in methane emissions from AWD. By reducing the number of irrigation events required, AWD can reduce water use by up to 30% (30).

Direct seeded rice (DSR) is a crop establishment system wherein rice seeds are sown directly into the field, as opposed to the traditional method of growing seedlings in a nursery, then transplanting into flooded fields. Compared to the conventional Puddled Transplanted Rice (PTR) method prevalent in Asia, DSR delivers faster planting and plant maturing, is more conducive to mechanization, conserves water scarce resources and reduces GHG emissions. Mechanized DSR also creates avenues for employment through new service provisions and is less labor intensive.DSR saves on labor, water (16-38%), cost of cultivation, and increases net income without yield penalty. It reduces methane emissions by significant ranges: 30-98% and Global Warming Potential by 20-44% (31).