Disentangling challenges to scaling alternate wetting and drying technology for rice cultivation: Distilling lessons from 20 years of experience in the Philippines

 Yuji Enriquez, Sudhir Yadav, Gio Karlo Evangelista, Donald Villanueva, Mary Ann Burac, and Valerien Pede   |  

The review’s findings point to the importance of rethinking the boundaries and assumptions of scaling theory of change for alternate wetting and drying; this requires proper consideration of the institutional and irrigation systems. There is a scaling gap in understanding and learning the contexts in which AWD could be successful and what it will take to succeed in most gravity-based irrigation systems.

In any rice-based developing economy, irrigation is a precondition for boosting agricultural production. But rising population, competing water uses among various sectors, and worsening climate conditions make it challenging for farmers to have sufficient water at the right place and at the right time.

Agriculture uses ∼70% of the planet’s freshwater supply, of which 40% is used for rice cultivation. As a staple food for half of humanity, more than 3 billion people rely on this crop as their main source of livelihood.

Therefore, enhancing rice production—and looking for ways to cultivate it with less water—is essential to assuring global food security.With current practices, rice production not only consume vast amounts of water; it also releases a significant amount of greenhouse gas (GHG) into the atmosphere.

An estimated 10% of global agricultural methane emissions are generated by rice production, and its cultivation is second only to livestock production as a source of methane emissions . While globally, rice production contributes only 1.5% of the total anthropogenic GHG, this share is much higher in rice-producing countries .

The Philippine agricultural sector is intricately linked to farm employment and the economy, water use, and GHG emissions. Agriculture is an essential pillar of the economy and is a significant water user in the country, accounting for 73% of the country’s total water consumption and secondlargest emitter of GHGs, contributing 53.7 MtCO2e to the national total emissions.

Annual per capita water availability in the Philippines has been in constant decline due to increased water demand. This results from economic and population growth and decreased water supply associated with the degradation of watersheds and climate change. In fact, the Philippines was rated the second most at-risk nation in 2018 by the 2020 Global Climate Risk Index and has consistently ranked in the top 20 since 2015.

The IPCC 2018 Special Report projects that a 0.5°C increase from the 1.5°C warming scenario will likely result in more severe climate change impacts and associated risks on ecosystems through increased temperature extremes and increased frequency and intensity of heavy precipitation and drought.

This is why the agriculture sector is a vital aspect of a country’s resilience building; it is not only the most vulnerable in terms of the devastating impacts of climate variability and increasing frequency of extreme weather events, it is also an important sector from the standpoint of mitigating climate change. Seventy percent of the area harvested to paddy rice comes from the irrigated ecosystems of the country, which contribute 77% of the total rice produced.

Of the total rice area, 3.26 million ha is under the irrigated environment and contributes 77% of the country’s total rice production. Clearly, to ensure water and food security, efficiencies in agriculture are required immediately. Rice production practices consume the largest share of water in the agricultural sector because most farmers practice continuous flooding throughout the cropping season.

Therefore, optimization of rice production through new management practices thatmaintain rice yields with greater water-productivity is essential to ensuring the country’s food security and access to freshwater for all.

Alternate wetting and drying (AWD), an irrigation scheduling technique for rice production, is a widely researched innovation for adapting agri-food systems to climate change, reducing environmental footprints, and ensuring a resilient and sustainable food production system..

AWD is a low-cost approach that enables farmers to adapt to increasingly water scarcity conditions, such as drought. When properly applied, AWD can increase overall farm production efficiency and mitigate GHG emissions.

The Philippines is one of the focus countries where AWD was first piloted and disseminated in the early 2000s. It has been reported that 60% of the Philippine farming area is climatically suited to AWD. In terms of CO2 emissions, is estimated that AWD can potentially mitigate 91.2 MtCO2e within a 2015–2050 timeframe.

For these reasons, the Philippine Government has taken steps to scale AWD in all national irrigation systems (NIS) and considers the technique a key adaptation and mitigation measure for meeting its Nationally Determined Contributions (NDC), the official country commitment for achieving the goals of the Paris Climate Agreement. It also serves as the basis for long-term public investments and a potential instrument for accessing international climate finance.

After two decades of scaling efforts, AWD adoption has been limited and much has yet to be achieved in terms of reaching the farmers nationwide.

In 2016, adoption was estimated at 60,559 farmers, covering 84,784 ha of land, which represents <5% of the total irrigated area of 1.86 million ha. There is growing interest from the government and development partners in the scaling out of this technology. This paper reviews the technological pathways to scaling AWD in the Philippines from 2000 to 2020 and aims to understand the different drivers and factors that influenced and constrained its success.

Through the lens of innovation uncertainty, this review analyzes how scaling interventions have dealt with knowledge uncertainties surrounding the adoption and benefits of AWD in various irrigation systems, how trade-offs occur across agroecological systems and governance scales, and how these interactions unraveled cross-scale and cross-level issues that ultimately mitigate the resulting outcomes and impacts.

The results show that AWD scaling efforts underwent iterative cycles of technological adaptation, promotion, and scaling. This trajectory is characterized by interdependent mechanisms including

  1. multi-stakeholder innovation platforms,
  2. participatory technology adaptation and transfer,
  3. capacity building for research and dissemination, and
  4. evidence generation and communication.

AWD’s early phases (2000–2010) involved a synergistic deployment of a multi-stakeholder platform and participatory technology testing, adaptation, and transfer. These mechanisms provided vertical and horizontal linkages that facilitated communication of evidence and institutional uptake by the Philippine Department of Agriculture and various stakeholders.

From 2011 to 2020, the country adopted new scaling pathways, including an institutional mechanism for accessing carbon credit and nationwide participatory demonstrations and trials for disseminating AWD. The carbon credit mechanisms did not flourish due to high transaction costs and trade-offs that occurred across the scale. The wide-scale participatory demonstration was also complemented by a policy issuance aligning irrigation scheduling of canal-based irrigation systems with the AWD schedule.

In the later stage, learning from AWD’s scaling experience culminated in the development of an IoT-powered decision support tool that provides irrigation advisory service to farmers and irrigation managers, making it easier to adopt AWD, efficiently manage water demand and delivery, and ultimately, sustainably manage water resources.

This technology is being benchmarked for applicability in different irrigation contexts. From the two decades of experience scaling this technology, several constraints to scaling AWD were rooted in the heterogeneity of irrigation contexts that were not anticipated in scaling strategies and the trade-offs that occur when AWD adoption and management reach cross-level and cross-scale.

AWD was found to be successful in small-scale pump-based irrigation systems. However, thus far, the scaling experience with large gravitybased systems has been mostly unsuccessful. The study reveals that several factors influence the scalability of AWD. These are economic incentives, institutional enforcement, excludability of access to unintended users, and quality of irrigation infrastructure. Conditions on these factors were more scale-fit in small-scale pump-based irrigations.

However, scaling AWD in large gravity-based irrigation systems is comparably more complex and confronts challenges underpinned by scale mismatches. These constraints cut across institutional enforcement, policy regimes and incentives, management and regulation, and the trade-off of benefit streams across livelihood and spatial scales.

Given that most irrigated rice-growing areas are in gravity-based irrigation systems, this explains why AWD’s impact is largely abated. Reflecting on the AWD scaling pathway pursued in the last two decades, the study finds that the dominant focus on product-orientation and technology transfer, and preference for controlled environments has neglected many of the important contextual factors, enabling policy incentives, institutions, and scale sensitivities that mitigated the impacts of AWD.

The review’s findings point to the importance of rethinking the boundaries and assumptions of scaling theory of change for AWD; this requires proper consideration of the institutional and irrigation systems. There is a scaling gap in understanding and learning the contexts in which AWD could be successful and what it will take to succeed in most gravity-based irrigation systems.

Much of this requires exploring these uncertainties; being open to failure, which is expected at least in the short term; and moving beyond scaling strategies driven mainly by technology demonstration of AWD in controlled field conditions. In order to bemore impact-oriented, it is necessary to reframe scaling theory to make it more relevant to farmers’ needs, including revenue generation and enhancing resilience to climate change. Addressing the problem of irrigation water must not solely focus on water e

fficiency, but also on ways of ensuring irrigation to farmers at all times. This shifts the focus from farmer-level water management to consider the entire system of irrigation water provisioning, where the capacity of the irrigation systems to monitor and inform water management decisions properly and ensure availability and flexibility of irrigation water is a critical change mechanism.

Thus far, researchers have generated enough evidence on the field-level impact of AWD; it’s time to look more broadly at opportunities that will trigger wide-scale adoption at the irrigation system scale to achieve significant irrigation water savings and reduce the carbon footprint.

Read the study:
Enriquez Y, Yadav S, Evangelista GK, Villanueva D, Burac MA, and Pede V. (2021) Disentangling challenges to scaling alternate wetting and drying technology for rice cultivation: Distilling lessons from 20 years of experience in the Philippines. Frontiers in Sustainable Food Systems, Vol 5


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