PubMed · 2026-01-01
In rice paddy soils, larger soil particle clusters called macroaggregates hold onto phosphorus far more effectively than smaller, tighter ones. Encouraging these larger clusters through organic amendments, reduced tillage, and careful water management offers a practical route to keeping nutrients in the soil and out of waterways.
Water-dispersible colloid concentrations rose 200-1400% and colloidal phosphorus increased 25-67% from surface to deeper soil horizons, showing strong depth-dependent dynamics.
Macroaggregates (2-0.25 mm) consistently retained more phosphorus than microaggregates (<0.25 mm), with SEM imaging confirming their larger, loosely bound structure gives them greater immobilization capacity.
Organic amendments, reduced tillage, and optimized water management were identified as the key levers for increasing macroaggregate abundance and reducing phosphorus runoff in paddy systems.
