South India’s large-scale agroecology programme
Our current food system is the largest driver of biodiversity loss worldwide. Around half of the Earth’s ice-free and otherwise habitable land is used to produce food (Ritchie and Roser, 2019), and over 80% of species at risk of extinction are threatened by agriculture (IUCN, 2025). If we are to feed the world and protect nature, then we need to enact a fundamental shift in the way we produce, trade, and consume food.
Agroecology[1] offers a framework for redesigning the food system. Practically, it integrates ecological principles into farming, while its social and political dimensions focus on equity, diversity, and resilience. The approach is already a prominent feature of many national and international sustainability agendas. For example, the Kunming-Montreal Global Biodiversity Framework contains a target that involves upscaling agroecological practices, and the UN Food Systems Summit identified agroecology as one of the systemic levers for change. However, despite the policy enthusiasm, rigorous evaluations of large-scale agroecological programmes are scarce, leaving us unsure whether they truly provide a path towards socioeconomic and biodiversity co-benefits. This is the information gap that our recent work sought to address (Berger et al., 2025a).
The world’s most extensive agroecological initiative is the Zero Budget Natural Farming (ZBNF) programme spanning 64,000 km2 (roughly the size of Sri Lanka) in the state of Andhra Pradesh, South India (RySS, 2025). Through farmer training programmes, the state government is encouraging farmers to adopt low-cost, microbe-enhancing farming practices that improve soil health and reduce dependence on agrichemical inputs and associated agribusinesses[2]. We wanted to know whether this actually works: Can farmers maintain or even increase their yields and make a decent living? How does it affect biodiversity?
Our study (Berger et al., 2025a) shows that ZBNF increases farmers’ profits and bird biodiversity, but vitally, it achieves both without reducing agricultural productivity. Thus, agroecological interventions at scale, such as ZBNF, are likely a key solution to reconciling food, sustainable livelihood, and conservation objectives.
How we evaluated the impact of Zero Budget Natural Farming
Evaluating ZBNF’s impacts required assessing the outcomes against appropriate benchmarks – known as counterfactuals – these are the outcomes that would have occurred without ZBNF transition.
If ZBNF had been randomly assigned to farms, simply comparing the outcomes between transitioned and non-transitioned farms would have been sufficient. However, ZBNF uptake was voluntary, so we had to account for possible confounding factors (i.e. those that might influence participation in the ZBNF programme and the outcome variables).
To do so, we selected thirteen ZBNF and thirteen agrichemical landscapes across northern Andhra Pradesh, based on key biophysical and socioeconomic confounders (such as agricultural suitability and market access) and then used statistical matching to select comparison units. At these sites we interviewed farmers to obtain information on yield and profit, and conducted bird surveys in the selected agricultural landscapes and in nearby natural forests. These forest surveys were essential, because quantifying the conservation value of natural habitat baselines is the only way to fully understand the potential and limitations of agroecological approaches for reverting regional biodiversity loss.
What we found
We showed that ZBNF generated equivalent yields and, by reducing input costs, more than doubled profits compared to agrichemical-based farming. ZBNF landscapes supported a greater densities of birds, including those that feed on agricultural pests which could have had yield benefits. Crucially, farmland trade-offs between bird densities and landscape-scale yields and profits were substantially less pronounced in ZBNF landscapes. This means that it is possible to increase yield and profit in ZBNF systems without losing as many birds as one would by doing the same in agrichemical systems. Nevertheless, most bird species of conservation importance were only found in forests. This is unsurprising as highly specialised species, which tend to be at greatest risk of extinction, are unable to live in agricultural lands of any sort. Therefore, scaling practices like ZBNF is insufficient to revert biodiversity loss, highlighting that agroecology initiatives need to be paired with strategies to protect and restore natural ecosystems.
Our study provides clear evidence the ZBNF programme is delivering positive outcomes for both people and nature and is an agroecological strategy worthy of support from policymakers, companies, and consumers in this South Indian context. However, to create additional co-benefits and limit the potential for unintended negative consequences, further action is needed: such as upscaling market-based sustainability approaches and enhancing regional biodiversity conservation capacity through financial and technical support.
Research and scaling priorities
ZBNF has received ample interest from numerous governments and NGOs across the tropics. Strong, equitable partnerships between these institutions and local farmers, researchers, and practitioners from Andhra Pradesh are needed to ascertain how ZBNF performs in different geographic contexts and, if appropriate, how ZBNF can be scaled nationally or regionally. Pilot studies are already underway in Zambia and Sri Lanka, but rigorous subsequent evaluations are needed. Researchers must work with farmers to tailor ZBNF practices to local biophysical and cultural settings and identify enablers of and barriers to widespread ZBNF uptake.
In addition, numerous fundamental natural science questions remain. Researchers should work to untangle the biophysical mechanisms by which ZBNF affects productivity and ecological outcomes. ZBNF appears to have positive impacts on below- (Duddigan et al., 2024) and above-ground (Berger et al., 2025b) ecosystem services, but further research on specific mechanisms are needed.
What needs to happen now
ZBNF’s roll-out in Andhra Pradesh has been enabled by strong political will and the creation of supporting services such as farmer training programmes, but supply chain transformations and changes in subsidy regimes are needed to create an even more conducive policy environment.
We found that ZBNF-specific value chains are absent or poorly developed, and that agrichemicals are subsidised. To promote the scaling of ZBNF, policy makers need to redirect agrichemical subsidies to ZBNF and support the creation of physical and institutional supporting infrastructure (such as tailored insurance products, post-harvest and market infrastructure, procurement policies for ZBNF produce, and strengthening of Farmer Producer Organisations). Voluntary sustainability standard professionals should explore how ZBNF can be integrated into existing certification schemes or whether a ZBNF-specific value brand can be created. Consumers can also help to create demand for ZBNF produce by informing themselves and buying products grown under ZBNF principles.
Finally, in Andhra Pradesh, food system and biodiversity conservation policies are largely separate (Berger et al., 2025c). ZBNF, and agroecological initiatives in general, must be coupled with area-based conservation measures, including national parks and community-based initiatives. Policy tools to deliver this include incentive programmes where payments to farmers or sustainability standard certification are conditional on natural habitat conservation. Researchers, policy makers, conservation practitioners, and farmers need to identify how such tools can be tailored to local contexts and design holistic policies that address food security, climate, and biodiversity goals simultaneously.
[1] Agroecology is a farming approach that works in harmony with nature, utilizing healthy soils, biodiversity, and local knowledge to create productive, resilient, and equitable food systems with reduced chemical inputs. The FAO has proposed that there are 10 core elements of agroecology: diversity, co-creation of knowledge, synergies, efficiency, recycling, resilience, human and social values, culture and food traditions, responsible governance, and circular and solidarity economies (FAO, 2018).
[2] ZBNF (also termed Andhra Pradesh Community Managed Natural Farming, APCNF) is a set of practices that boost soil life, protect young plants, and keep the ground covered. It improves soil structure, so farmers need less water and tilling, and the ZBNF programme encourages intercropping, using pest-repelling plants, and adding trees and bird perches to support a healthier agroecosystem.
