When imagining how to maximize agricultural productivity in the future, it is easy to picture vast monocrop fields maintained by drones and agrichemicals. Yet there are alternative pathways that might enable both high yields and greater sustainability, by enhancing the ecological processes underpinning crop growth and health. These ‘agroecological’ farming approaches may benefit a wide range of farmland biodiversity – not only the organisms that contribute towards food production through pollination and pest predation.
For my PhD research, I examined the crop yield, livelihood, and biodiversity impacts of one of the most ambitious agroecological transitions currently underway: the Zero Budget Natural Farming (ZBNF) programme in South India.
What is Zero Budget Natural Farming?
The term ‘Zero Budget’ refers to the absence of costly inputs: ZBNF was designed for marginalized smallholders who often face crippling debt cycles linked to the rising costs of agrichemicals. By relying on locally available, non-synthetic inputs, ZBNF aims to reduce production costs to near zero. ‘Natural Farming’ refers to the aim of regenerating yield-supporting ecosystem services, with farmers producing microbial formulations that are believed to improve soil health, enhancing the efficiency of nutrient and water use.
I first came across ZBNF when I was preparing for my PhD interview and I was intrigued by anecdotal reports of positive yield and social outcomes. I was astonished by the scale at which this agroecological transition was happening: the government of Andhra Pradesh is aiming to convert all six million farming households in the state from conventional, agrichemical systems to ZBNF — a transformation of unprecedented scale in modern agriculture. However, the underlying evidence was base extremely thin.
Research Approach
I spent 14 months living and working in this hot, humid region, hosted by farming and tribal communities whose hospitality was as warm as their cooking was spicy. I documented my experiences in previous blogposts: Part 1 and Part 2.
My fieldwork combined farmer interviews with ecological monitoring. To assess biodiversity impacts, I surveyed birds visually and acoustically, using them as indicators of wider biodiversity responses. Surveys were conducted on ZBNF and conventional farms, and, crucially, on neighbouring natural habitat: to understand an agricultural strategy’s potential and limitations for improving biodiversity, it is essential to view the system in the light of a natural ecosystem baseline – in this case, nearby forests.
This comparative approach allowed me to evaluate ZBNF not only in terms of yields and livelihoods, but also through its broader contributions to biodiversity conservation.
Key Findings
My results were recently published in Nature Ecology & Evolution and showed that ZBNF:
- Doubled farmers’ net profits compared to conventional, agrichemical-based agriculture.
- Maintained yields at levels comparable to agrichemical-based farming.
- Improved bird biodiversity outcomes, with higher bird abundances relative to conventional landscapes.
These findings demonstrate that ZBNF is an agricultural strategy that works for both people and nature, providing hope that it might be possible to both feed the world and reverse biodiversity loss.
However, the study also revealed limits. Agricultural landscapes under ZBNF, though more biodiversity-friendly than their agrichemical counterparts, cannot replicate the ecological richness of natural forests. Many bird species of conservation concern were restricted to forest habitats, underlining the irreplaceable role of intact ecosystems and the need to design holistic policies that effectively integrate agriculture with nature conservation.
