A compost experiment combining rice stubble, rock phosphate and cow dung found CP4 (40:30:30) had the most favourable compost properties and produced 97.1 mg/kg available soil phosphorus after okra. Compost increased phosphorus activation and very labile carbon versus control, but compost formulations did not differ in pod yield or N/P uptake. The main signal is soil improvement, not superior yield from one formula.
Key findings
- CP4 (40% stubble, 30% rock phosphate, 30% cow dung) had favourable properties and yielded 97.1 mg/kg available P. Formulas did not differ in pod yield or N/P uptake, although compost treatments differed from control. PAC and active carbon, especially the very labile fraction, increased.
Why this matters globally
The approach may reduce stubble burning and restore soils in rice–vegetable systems, but cost, logistics, composting emissions, pathogen risk and multi-season outcomes require evaluation.
Thai researcher contribution
Saychol Sukyankij of Phranakhon Si Ayutthaya Rajabhat University studied a major Thai rice residue and its soil effects directly, linking local waste management with nutrient cycling.
Limitations to consider
Method and statistical details are limited. One crop cycle may not represent farms; more very labile carbon is not long-term sequestration, and rock phosphate or manure composition varies by source.