Mekong Delta rice farming has long been said to be "something you do by experience." The timing of sowing, how water is let in, the amount of fertilizer spread—every one of them is supported by intuition handed from parent to child. Yet in one strongly acidic corner of An Giang province, a farmer who replaced that intuition with soil design is turning a profit by not killing the rice and reducing chemical fertilizer and pesticides. Not a flashy yield increase but the unglamorous step forward of rice farming that can be done even on poor land becomes material not to be overlooked by those sourcing low-pesticide rice for Japan.
The single paddy that was the starting point
What Vietnamese agricultural media reported is the story of Tran Van Phuoc, who has grown rice for over 30 years in Long Thuan, Thanh My Thai commune, An Giang province. Of the more than 14 hectares he owns, in the 2025 summer-autumn crop he put 3.9 hectares into a soil-building model called "Hanh Trinh Xanh" (Green Journey). The core lies at the entrance of the cropping season. He had conventionally used general-purpose fertilizer available at nearby shops, but he received technical guidance at a training session and applied a material for acidic soil called Bio-Canxi as a base fertilizer one to two days before sowing. As a result, roots that had been short and darkened now grew white, numerous, and deep, he says. In the subsequent topdressing he reduced chemical fertilizer by 10 to 15%, and because the rice was healthy, pesticides too could be held down.
The premise of the Mekong's acidic soil
Phuoc's field lies in a low-lying wetland called the Tu Giac Long Xuyen (Long Xuyen Quadrangle), where during the rainy season's flooding the sulfur in the soil produces acid, the pH drops, and the rice roots are damaged. It is a so-called acid sulfate soil (locally called "phen"), and seedlings withering right after sowing and needing to be replanted was a chronic trouble. What works here is neither a variety nor a pesticide but the single move of adjusting the soil's pH and toxicity at the start of the cropping season. Because fertilizing by intuition takes "the usual amount" as its baseline, the more acidic the year, the more easily it misses. The idea of designing the base fertilizer by back-calculating from the soil's condition makes the most difference on poor land.
In this zone the soil's character swings greatly between the rainy and dry seasons. Sulfur that oxidized in the dry season dissolves again under the rainy season's flooding, and the paddy surface's pH rises and falls by year. That is exactly why fertilizing premised on "the same amount as last year" carries the risk of losing seedlings in a year when acidity comes out strong. Conversely, if the base fertilizer can be adjusted by measuring the soil's condition each cropping season, a steady harvest becomes foreseeable even in a bad year. The order of thinking—filling with the design of the soil itself the part that variety improvement or additional pesticide input cannot reach—is the heart of this case.
The difference between relying on experience and soil design
| Item | Conventional (experience-based) | Shift to soil design |
|---|---|---|
| Base-fertilizer timing | Follows the usual custom | Applied one to two days before sowing |
| Material used | General-purpose fertilizer from nearby shops | Dedicated material for acidic soil |
| Root condition | Short and darkened | White, numerous, and deep-growing |
| Seedling die-off | Occurs from acid toxicity, requiring replanting | Die-off decreases, replanting shrinks |
| Chemical fertilizer in topdressing | Conventional amount | Reduced by 10 to 15% |
| Pesticides | Conventional amount | Rice is healthy, so use is held down |
The figures are limited to those that could be confirmed in the source article. Because concrete amounts for yield or profit are not given, we do not step into them here. Even so, the value of this case lies in the point that the two—"not killing" and "reducing"—stand at the same time.
The local reception
Phuoc says, "Farmers only believe once they see with their own eyes. So I do it first and show everyone the effect." It is a felt sense that the entrance to adoption is not flashy advertising but showing the roots in the next paddy over. He also reveals that the reason he, who had used only general-purpose fertilizer, reached for a dedicated material was that the training session and technical guidance pushed him forward.
This soil-building model has been deployed in the Mekong Delta and Tay Ninh province from the 2025 summer-autumn crop, with the fertilizer maker Binh Dien supplying the material and the agronomy expert Nguyen Bao Ve and others joining to advise. That the administration's extension program, private-sector materials, and researchers' knowledge mesh in a single paddy is the dividing line from conventional "intuition-only" rice farming.
Lessons for Japanese low-pesticide rice sourcing
Seen from the standpoint of sourcing rice on the Japanese side, what deserves attention is not a story of yield but a story of reproducibility. Low-pesticide, reduced-chemical-fertilizer rice can only be used as a supply source when the cultivation records are consistent. A farmer who prepares the soil at the entrance of the cropping season and manages subsequent input amounts by numbers can repeat the same procedure the next year too. Whereas intuition-reliant fields have input amounts that vary year by year, making residue and quality variation hard to track, a soil-design-type field leaves "when, what, and how much" on record. For a buyer who wants to buy reduced-pesticide rice stably, this very recordability becomes material for a sourcing decision.
One more point: rice farming that can be done on poor land widens the base of supply. If, rather than fighting over only prime paddies, disadvantaged fields like acid soil can be made productive, the options for supply sources increase. A perspective is needed of building the presence or absence of such cultivation design into sourcing criteria, not just the unit price.
There is also something to note on the cost-structure side. The dedicated material has a higher unit price than general-purpose fertilizer, so the initial input increases. Even so, the labor of replanting and the seed rice decrease, the topdressing's chemical fertilizer is cut by a little over 10%, and pesticides are held down too. If the balance pencils out, the farmer has an incentive to choose the same design the next year. Seen from the buyer's side, the more a growing region has an economics that makes farmers want to continue, the less likely supply is to break off. The paradox here is that a field where farmers can keep turning a profit leads, in the end, to more stable sourcing than a one-off field you can beat down on price.
Ripple effects on the industry
This move also changes the relationship between material makers and growing regions. The axis is shifting from a business of selling general-purpose fertilizer by volume to a business of providing, as a set, materials and guidance matched to each field's soil. For a buyer Japanese company, by looking at what kind of technical-support framework lies behind the growing region, you can gauge the reproducibility of that rice. Conversely, a one-off from a field with neither guidance nor records is unsuited to continued sourcing, even if the price is low. The flow of the growing-region-selection gaze shifting from "the field's conditions" to "the mechanism that manages the field" applies not only to rice but to the sourcing of vegetables and fruit as well.
Practical information
When considering acid-soil rice from the Mekong Delta, including An Giang province, you first want to confirm the soil-building process at the start of the cropping season. Whether the type and timing of the base fertilizer, the presence or absence of pH adjustment, and how much topdressing and pesticides were reduced are recorded becomes one axis of judgment. Next, look at whether that field is a one-off demonstration or part of a framework continuing over multiple cropping seasons. A model in which the administration, makers, and researchers are involved, like Hanh Trinh Xanh, makes continuity from the next year onward easy to read. If sample rice is obtained together with the cultivation history, not just residue and taste, you can estimate in advance the variation when moving to mass production. A realistic approach is to start with trial imports in small lots and confirm whether quality lines up across cropping seasons with the same farmer and the same design. In addition, you want to grasp who is providing technical guidance locally. A field in which material makers, researchers, and administrative extension workers are involved allows you to inquire into the cultivation process through the person in charge and makes backing up the records easier. That the window to the growing region is open not only to the individual farmer but also to the guiding expert tells in negotiations for continued sourcing too.
Summary
What happened in An Giang's acid soil was not a miracle of increased yield but a shift in thinking. Stop the usual fertilizing, design the soil's pH and toxicity at the entrance of the cropping season, and reduce subsequent inputs by numbers. This very unglamorous procedure produces the reproducibility that low-pesticide rice for Japan requires. Rice farming that turns poor land into a productive force holds a sourcing value that cannot be seen from a price list alone. When selecting a growing region, we want to look at the mechanism that manages the field as much as the field's conditions.
Sources
- Nông nghiệp Môi trường「Làm giàu nhờ đổi mới tư duy trên vùng đất phèn」
- Cutting chemical fertilizer for 200,000 yen in profit: the sourcing window opened by An Giang organic rice
- The day farmers become crop doctors: Quang Ninh's reduced-pesticide rice opens sourcing to Japan
- Palm sugar and fish sauce head to Australia with five stars: the raw-material map An Giang's OCOP draws
