How Cow Dung and Nitrogen Are Revolutionizing Mustard Farming in Coastal Bangladesh
In the vast coastal regions of Bangladesh, a quiet agricultural revolution is underway. For decades, these fertile lands have been dominated by a single crop—rainy season rice—leaving fields barren during the crucial dry rabi season from November to March. This isn't by choice but necessity, as increasing soil salinity makes traditional farming increasingly difficult. Meanwhile, Bangladesh faces a growing demand for edible oils, with consumption increasing by approximately 20% over five years 1 .
Mustard isn't just any crop—it's the world's third-largest source of vegetable oil and represents an opportunity for coastal farmers to diversify their income while contributing to national food security 2 .
Recent research has revealed that the strategic combination of two powerful fertilizers—traditional cow dung and synthetic nitrogen—could unlock the potential of these saline soils, yielding surprising results that blend ancient wisdom with modern science.
Bangladesh's coastal areas face a perfect storm of agricultural challenges. As sea levels rise and climate patterns shift, saltwater intrusion has become increasingly problematic, creating soils where many crops struggle to survive. The situation worsens as the dry season progresses, with late-sown crops facing even higher salinity levels 1 .
Mustard plants, like all crops, have particular sensitivity during their early growth stages, making the initial weeks after planting critical for their survival and ultimate yield.
The research explores two complementary approaches to overcoming soil salinity:
What makes this approach innovative is how these two fertilizer types work together—the quick-release synthetic nitrogen provides immediate nutrition, while the slow-release organic cow dung creates sustainable soil health improvements.
Major constraint for coastal agriculture
Improves soil structure and water retention
Essential for plant growth and development
To determine the optimal fertilizer strategy for mustard in coastal Bangladesh, researchers designed a comprehensive experiment at the agriculture field laboratory of Noakhali Science and Technology University from October 2021 to January 2022 3 . The study employed a Randomized Complete Block Design (RCBD) with three replications—a rigorous approach that ensures results are statistically significant and not due to random chance.
This created 16 different treatment combinations, from completely unfertilized plots to heavily amended ones, allowing researchers to observe not just individual effects but how these two fertilizers interact 3 .
The highest seed yield (1.77 t ha⁻¹) was obtained from the combination of 45 t ha⁻¹ cow dung with 300 kg ha⁻¹ nitrogen—nearly double the yield of the unfertilized control treatment, which produced a meager 0.93 t ha⁻¹ 3 .
When examined separately, both cow dung and nitrogen demonstrated significant benefits for mustard growth and yield. The highest application rates for both fertilizers produced the best results across all measured parameters 3 .
| Cow Dung Dose (tons/ha) | Seed Yield (tons/ha) |
|---|---|
| 0 (Control) | Lowest |
| 15 | Moderate Increase |
| 30 | Significant Increase |
| 45 | Highest |
The most revealing findings emerged from examining how cow dung and nitrogen work together. The research revealed a clear dose-dependent relationship—as application rates of both fertilizers increased, so did the yield 3 .
| Treatment | Seed Yield (tons/ha) | Increase |
|---|---|---|
| Control (No fertilizer) | 0.93 | Baseline |
| Max Cow Dung Only | 1.39 | 49% |
| Max Nitrogen Only | 1.45 | 56% |
| Combination (Both Max) | 1.77 | 90% |
| Cow Dung (tons/ha) | Nitrogen Application (kg/ha) | |||
|---|---|---|---|---|
| 0 | 100 | 200 | 300 | |
| 0 | 0.93 | 1.12 | 1.30 | 1.45 |
| 15 | 1.08 | 1.28 | 1.47 | 1.62 |
| 30 | 1.24 | 1.45 | 1.63 | 1.75 |
| 45 | 1.39 | 1.58 | 1.69 | 1.77 |
Table: Combined effect of cow dung and nitrogen on mustard seed yield (tons/hectare) 3
Yield Increase with Optimal Combination
Highest Recorded Yield
Treatment Combinations Tested
Behind these meaningful findings lies a carefully selected array of research materials and methods.
Typically applied as urea, this synthetic fertilizer delivers readily available nitrogen crucial for plant growth 3 .
This rigorous experimental layout controls for spatial variability in the field 3 .
Essential for tracking temperature, rainfall, and evaporation rates 1 .
The implications of this research extend far beyond the experimental plots in Noakhali. The strategic combination of cow dung and nitrogen represents a practical, scalable solution for coastal agricultural challenges—one that balances immediate productivity gains with long-term soil health. For farmers in coastal Bangladesh, these findings offer a roadmap to transforming fallow dry seasons into productive growing periods, potentially doubling their mustard yields while building more resilient farming systems.
Perhaps the most encouraging aspect of this research is how it bridges traditional knowledge and modern science. Cow dung has been used in South Asian agriculture for millennia, but now we understand precisely how and why it works in partnership with synthetic fertilizers to overcome contemporary challenges like soil salinity.
As climate change continues to alter coastal ecosystems around the world, such research becomes increasingly valuable. The lessons learned in Bangladesh's coastal mustard fields may well inform sustainable agricultural practices in saline-affected regions globally, contributing to greater food security in a changing world.
With rising sea levels and increasing soil salinity affecting coastal agricultural regions worldwide, the findings from this research could help: