we are rice farmers, but a lot of the rice land, including the terraces in the mountains, were built slowly, with irrigation and enriching the soil with weed debris, ash from burning, etc.
Science has an article on how Indonesia's attempt to make huge areas of former swamps and forests into productive rice land may be doomed.
the problem seems to be that these soils are thin and acidic.
this can be treated but much of the rice land in use has been lovingly improved over hundreds of years by irrigation, weed control, manure and rotting organic matter for fertilizer, and sometimes adding minerals like lime to sweeten the soil
IRRI book on soil problems for you to download.
it instructs about caring for the soil in a way to limit chemicals and discusses the wet /dry method of growing rice.
one way to improve acidic soil is to use lime in the fertilizer.
but opening new areas for rice cultivation requires soil analysis and working with local farmers on the best way to improve the soil. You need to find a type of rice that will grow with the climate, and you need to decide if you want wet or dry or wet/dry method of irrigation. And of course, you need the government to dig you irrigation canals, and government assistance to keep you going in the bad years: because it may take years until the fields are evolved from brush into productive land.
China did this two thousand years ago, so it's not impossible.
when I read Science article I interpreted the problem as being too ambitious: sort of let's destroy the forest and just import farmers from another area to plant rice and voila, instant crop.
No. It's more complicated than that.
The article goes into previous mega plans that failed; much of the failure is from magical thinking, but when the authors keep mentioning that the indigenous need the forest, as if hunter gathering lifestyle would feed the growing population, it shows another bias: the love of the primitive in NGOs who are supposed to help farmers to modernize.
the love of the primitive. Nice in theory but hell in reality.
I remember a nice happy film about a village in the Visayas where the happy happy people assured the film makers they loved their traditional rice growing style.
Two problems with that film however.
One: In Filipino culture, one tends to tell the questioner what he wants to hear, not the truth.
Two: Our relatives are from that area and people are always asking us if we can hire them to work on our farms in Luzon. That area is poor. Poor is nice to visit, but hell on the locals, who see their malnourished kids die of infections, and who are old and arthritic by age 50. Obviously the film makers didn't ask any of these people about how they like their traditional lifestyle.
Indeed, this is why ten percent of the Philippine population work overseas, either as permanent migrants, temporary workers, or as sailors in international shipping.
we have two rice businesses here in Luzon:
One on the fields once owned by our family but distributed to local farmers under land reform. We grow rice on the small plots we own, and subcontract with these farmers to grow rice organically and buy it from them and distribute it to the supermarkets in Manila.
And because of this expertise, Joy, who has business background, was asked to start a coop to work with farmers in nearby Bulacan to grow organic rice and vegetables.
well, anyway, it is late an I am too lazy to go into details of how to make thin acidic soil into productive rice land, so I asked Grok how to do this
grok answer to how to change acidic soil into productive rice land:
Converting acidic soil into suitable land for rice growing involves adjusting the soil's pH and improving its fertility and structure. Rice typically thrives in slightly acidic to neutral soils (pH 5.5–7.0), though some varieties can tolerate more acidic conditions. If your soil is highly acidic (below pH 5.5), you'll need to take steps to neutralize it and create a favorable environment. Here's a step-by-step guide:
1. Test the Soil
Why: Determine the current pH and nutrient levels of your soil.
How: Use a soil testing kit (available at garden stores) or send a sample to a local agricultural extension service.
Goal: Aim for a pH range of 5.5–7.0, ideal for most rice varieties.
2. Raise the Soil pH (if too acidic)
Liming: Apply agricultural lime (calcium carbonate) or dolomite lime (calcium magnesium carbonate) to neutralize acidity.
Amount: Depends on soil type and current pH. For example:
Application: Spread evenly over the soil and incorporate it 15–20 cm deep using a plow or tiller. Do this 2–3 months before planting to allow the lime to react with the soil.
Recheck: Test the pH again after a few weeks to ensure it’s in the target range.
3. Improve Soil Fertility
Organic Matter: Add compost, manure, or green manure (e.g., decomposed rice straw or legumes) to boost nutrients and improve soil structure.
Fertilizers: Based on your soil test, apply:
Nitrogen (e.g., urea) for growth.
Phosphorus (e.g., superphosphate) for root development.
Potassium (e.g., potassium chloride) for overall health.
Typical rates: 100–150 kg/ha nitrogen, 40–60 kg/ha phosphorus, 40–60 kg/ha potassium (adjust based on soil needs).
4. Prepare the Land for Rice
Water Management: Rice grows best in flooded or waterlogged conditions (paddy fields). Ensure your land has access to water and can retain it.
Tilling: Plow the soil when moist to break up clumps and create a muddy, puddled texture ideal for rice transplanting or sowing.
5. Choose the Right Rice Variety
Some rice varieties tolerate acidic soils better than others (e.g., upland rice for drier, acidic conditions vs. lowland rice for paddies). Consult local agricultural experts for varieties suited to your region.
6. Maintain the Soil
Flooding: Keeping the field flooded can naturally suppress soil acidity over time by limiting oxygen and altering chemical reactions.
Monitor: Regularly check pH and nutrient levels, especially after each growing season, and amend as needed.
Tips
Work with local farmers or agricultural advisors—they’ll know what works best in your area.
Avoid over-liming, as a pH above 7.5 can lock up nutrients like iron and zinc, which rice needs.
With these steps, your acidic soil can be transformed into productive rice-growing land over one or two seasons, depending on how acidic it starts out. Let me know if you need specifics for your location or soil type!
