Leaf Color Chart Distribution Pilot
INDIND -22 -3122Last modified on December 19th, 2025 at 10:42 am
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Abstract
Farmers in low and middle-income countries face multiple barriers to optimizing agricultural decisions and often don’t have access to actionable information to adapt their practices. These challenges are particularly salient in fertilizer application: Returns to fertilizer are highly heterogeneous, which makes it difficult for farmers to observe the effectiveness of their actions. With large fertilizer subsidies in South Asia, many farmers overuse nitrogen fertilizers. A Leaf Color Chart (LCC), a simple plastic strip with graduated green shades, provides both real-time estimates of a crop’s nitrogen status and rule-of-thumb guidance on correct quantities of urea fertilizer to apply to address the crop’s need for nitrogen.
We piloted a light-touch intervention to encourage the use of LCCs by cotton farmers in Gujarat, India. The pilot experiment was designed to generate suggestive insights on farmers’ interests and the barriers to using LCCs, and to elicit the farmers’ feedback. We randomly assigned 32 villages to four distribution channels, namely PxD, a non-governmental organization (NGO) partner, agro-dealers, and peer farmers, and distributed LCCs to a total of 418 randomly selected farmers, who all received a context-specific instruction booklet and digital advisory. We saw wide use of the tool: More than half of the cotton farmers who received an LCC reported using the tool. Distribution by agro-dealers and by peer farmers were the most promising distribution channels for LCC adoption and accurate recall of LCC usage instructions, relative to the benchmark in-person distribution by PxD staff. Preliminary findings suggest that, on average, the farmers who received LCCs reported applying 35% less nitrogen fertilizer and harvesting 11% more than those who did not. -
Status
Completed
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Start date
Q2 May 2022
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Experiment Location
India / Gujarat, India
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Partner Organization
_N/A
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Agricultural season
Kharif
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Experiment type
Other
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Sample frame / target population
Cotton farmers Gujarat
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Sample size
830
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Outcome type
Farming practices, Input adoption
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Mode of data collection
PxD administrative data, Partner administrative data, In-person survey, Phone survey
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Research question(s)
1. Which distribution channels are most promising for farmers to receive and use LCC?
2. Do farmers who receive LCCs reduce the overuse of nitrogen fertilizer compared to those who do not?
3. Do farmers who receive LCCs maintain or increase their cotton yield compared to those who do not? -
Research theme
Agricultural management advice, Input recommendations, Service design, Soil fertility
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Research Design
We randomly assigned four types of LCC distribution methods at the village level, stratified by district and whether PxD’s service penetration rate in the village was above or below the median. We assigned treatment randomly to infer results clearly and at the village level, as some distribution types had a higher risk of spillovers than others did. We designed the pilot to provide preliminary insights on the efficacy of the different distribution channels, in order to rule out mechanisms that are unlikely to work and to gather qualitative insights on whether and how farmers use the tool. With only 32 villages and 830 farmers in the pilot, the study was not designed to detect significant differences in distribution channels or causal impacts of receiving LCCs on farmer outcomes.
We facilitated the distribution of LCCs to 418 farmers, provided them with a context-specific instruction booklet, and delivered advisory content over the phone with behavioral nudges on how and when to use LCCs. We sent these messages every week from the start of the sowing period in Gujarat, for three weeks.
During May 2022, we tested the following LCC distribution mechanisms:
- By visiting farmers door-to-door, PxD’s staff distributed LCCs directly to 231 farmers and trained the farmers on the correct use of the LCC.
- PxD partnered with an NGO local foundation that regularly interacts with an extensive network of cotton farmers in-person. PxD used a train-the-trainers model to ensure the NGO’s staff could properly train farmers on the use of the LCC. The NGO foundation distributed LCCs to 115 farmers and trained them during their village meetings.
- PxD’s staff trained four agro-dealers to distribute LCCs to their customers, since we had confirmed through our scoping activities that agro-dealers are a primary source for farmers of information about the application of nitrogen fertilizer. Twenty-two farmers in total received LCCs from these four agro-dealers.
- PxD distributed LCCs to 19 farmers and asked each of these farmers to distribute two additional LCCs to their peers. Thirty-one farmers in these villages received an LCC from their peers in the village.
Throughout the pilot, we also followed up with 412 control farmers who did not receive the LCC.
We conducted a phone midline survey during August–September 2022, in-person focus group discussions and qualitative interviews during October 2022, and an in-person end-of-season survey during November 2022–January 2023, to understand whether LCC recipients changed their nitrogen-use patterns and the impact of LCCs on other farming outcomes.
We used the cost of cotton production in Gujarat, as described in Cole and Fernando (2021), to estimate potential cost reductions for farmers who receive an LCC.
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Results
The most promising distribution channels for LCC adoption and accurate recall of LCC-usage instructions were distribution by agro-dealers and by peer farmers, relative to the benchmark in-person distribution by PxD staff. The NGO distribution channel reached substantial scale by distributing large quantities of LCC compared with other indirect channels. However, qualitative data revealed implementation challenges: Farmers who received LCCs through this NGO channel were less likely to recall having received the tool and had lower recall of how to use it. By comparison, 93% of the farmers who received LCCs through PxD, agro-dealers, or peer farmers recalled receiving the LCC, with 82% reporting that they still had their LCC at the end of the pilot project, and 54% reporting that they used their LCC during the season. Farmers who received an LCC from the NGO had the lowest engagement with the digital extension service (average pick-up rates of 60% for calls about LCCs) compared to those who received LCCs from PxD, peer farmers, or agro-dealers (average LCC-call pick-up rates of 75–85%). Quantitative and qualitative data suggest that, compared with farmers receiving LCCs directly from PxD, the farmers who received LCCs from agro-dealers and peer farmers were more educated and, at baseline, had higher average nitrogen-fertilizer use. This pattern suggests that local agents such as agro-dealers and farmers may be more effective at identifying and reaching farmers who are more likely to use and benefit from the LCCs, such as those who can read, those with high nitrogen-fertilizer use patterns, or those who are more willing to try new technologies.
Preliminary findings suggest that cotton farmers who received an LCC used 35% less nitrogen on average than those who did not. The effect is likely driven by decreases in fertilizer use by those farmers who were overusing it at baseline. Our analysis also suggests a smaller positive effect on yield: Farmers who received the LCC had an 11% increase in average yields compared with those who did not receive the LCC. However, this is not statistically significant.
Based on PxD’s previous data on the average cost of production of cotton in Gujarat, as described in Cole and Fernando (2021), we estimate that these results could translate to a decrease of at least 4.3% in the cost of production per acre, due to the reduction in nitrogen-fertilizer use by farmers who receive an LCC.