Incubation study demonstrates temporal shifts in labile phosphorus pools across amended soils, highlighting the impact of soil properties and extraction methods on nutrient release.
Key Points
To quantify temporal changes in labile soil phosphorus pools across contrasting soil types amended with struvite or monoammonium phosphate over a 112-day plant-free incubation.
Incubated contrasting soils—a neutral-pH sandy clay loam and an alkaline clay—without plants for 112 days.
Applied granular struvite or monoammonium phosphate (MAP) at rates of 100 and 200 mg P kg⁻¹.
Measured water-extractable phosphorus (WEP) and Olsen-P concentrations at multiple intervals following soil sample grinding.
Water-extractable phosphorus and Olsen-P concentrations were initially higher under high-rate struvite than high-rate MAP, likely influenced by granule fragmentation during sample grinding.
Water-extractable phosphorus declined over time across treatments and converged by Day 112, while Olsen-P in high-rate struvite fell below high-rate MAP by Day 70.
Olsen-P was consistently lower in the neutral sandy clay loam than in the alkaline clay, whereas initial high-rate water-extractable phosphorus was greater in the sandy clay loam.